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Separating the calculation core in a new class. It is not yet ready.

Ovidio Peña Rodríguez 10 years ago
parent
commit
fd8d92ade7
6 changed files with 1840 additions and 71 deletions
  1. 1 1
      go.sh
  2. 1595 0
      nmie-core.cpp
  3. 178 0
      nmie-core.h
  4. 54 57
      nmie-wrapper.cc
  5. 11 13
      nmie-wrapper.h
  6. 1 0
      scattnlay.cpp

+ 1 - 1
go.sh

@@ -10,7 +10,7 @@ rm -f ../scattnlay
 
 #google profiler  ######## FAST!!!
 echo Uncomment next line to compile compare.cc
-#g++ -Ofast -std=c++11 $file nmie.cc nmie-wrapper.cc -lm -lrt -o scattnlay.bin /usr/lib/libtcmalloc.so.4 -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free -march=native -mtune=native -msse4.2
+g++ -Ofast -std=c++11 $file nmie.cc nmie-wrapper.cc -lm -lrt -o scattnlay.bin /usr/lib/libtcmalloc.so.4 -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free -march=native -mtune=native -msse4.2
 
 #  g++ -Ofast -std=c++11 compare.cc nmie.cc nmie-wrapper.cc -lm -lrt -o scattnlay-g.bin -ltcmalloc -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free -g
 

+ 1595 - 0
nmie-core.cpp

@@ -0,0 +1,1595 @@
+//**********************************************************************************//
+//    Copyright (C) 2009-2015  Ovidio Pena <ovidio@bytesfall.com>                   //
+//                                                                                  //
+//    This file is part of scattnlay                                                //
+//                                                                                  //
+//    This program is free software: you can redistribute it and/or modify          //
+//    it under the terms of the GNU General Public License as published by          //
+//    the Free Software Foundation, either version 3 of the License, or             //
+//    (at your option) any later version.                                           //
+//                                                                                  //
+//    This program is distributed in the hope that it will be useful,               //
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                 //
+//    GNU General Public License for more details.                                  //
+//                                                                                  //
+//    The only additional remark is that we expect that all publications            //
+//    describing work using this software, or all commercial products               //
+//    using it, cite the following reference:                                       //
+//    [1] O. Pena and U. Pal, "Scattering of electromagnetic radiation by           //
+//        a multilayered sphere," Computer Physics Communications,                  //
+//        vol. 180, Nov. 2009, pp. 2348-2354.                                       //
+//                                                                                  //
+//    You should have received a copy of the GNU General Public License             //
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.         //
+//**********************************************************************************//
+
+//**********************************************************************************//
+// This class implements the algorithm for a multilayered sphere described by:      //
+//    [1] W. Yang, "Improved recursive algorithm for light scattering by a          //
+//        multilayered sphere,” Applied Optics, vol. 42, Mar. 2003, pp. 1710-1720.  //
+//                                                                                  //
+// You can find the description of all the used equations in:                       //
+//    [2] O. Pena and U. Pal, "Scattering of electromagnetic radiation by           //
+//        a multilayered sphere," Computer Physics Communications,                  //
+//        vol. 180, Nov. 2009, pp. 2348-2354.                                       //
+//                                                                                  //
+// Hereinafter all equations numbers refer to [2]                                   //
+//**********************************************************************************//
+#include "nmie-core.h"
+#include <array>
+#include <algorithm>
+#include <cstdio>
+#include <cstdlib>
+#include <stdexcept>
+#include <vector>
+
+namespace nmie {  
+  //helpers
+  template<class T> inline T pow2(const T value) {return value*value;}
+
+  int round(double x) {
+    return x >= 0 ? (int)(x + 0.5):(int)(x - 0.5);
+  }  
+
+
+//**********************************************************************************//
+// This function emulates a C call to calculate the actual scattering parameters    //
+// and amplitudes.                                                                  //
+//                                                                                  //
+// Input parameters:                                                                //
+//   L: Number of layers                                                            //
+//   pl: Index of PEC layer. If there is none just send -1                          //
+//   x: Array containing the size parameters of the layers [0..L-1]                 //
+//   m: Array containing the relative refractive indexes of the layers [0..L-1]     //
+//   nTheta: Number of scattering angles                                            //
+//   Theta: Array containing all the scattering angles where the scattering         //
+//          amplitudes will be calculated                                           //
+//   nmax: Maximum number of multipolar expansion terms to be used for the          //
+//         calculations. Only use it if you know what you are doing, otherwise      //
+//         set this parameter to -1 and the function will calculate it              //
+//                                                                                  //
+// Output parameters:                                                               //
+//   Qext: Efficiency factor for extinction                                         //
+//   Qsca: Efficiency factor for scattering                                         //
+//   Qabs: Efficiency factor for absorption (Qabs = Qext - Qsca)                    //
+//   Qbk: Efficiency factor for backscattering                                      //
+//   Qpr: Efficiency factor for the radiation pressure                              //
+//   g: Asymmetry factor (g = (Qext-Qpr)/Qsca)                                      //
+//   Albedo: Single scattering albedo (Albedo = Qsca/Qext)                          //
+//   S1, S2: Complex scattering amplitudes                                          //
+//                                                                                  //
+// Return value:                                                                    //
+//   Number of multipolar expansion terms used for the calculations                 //
+//**********************************************************************************//
+  int nMie(int L, std::vector<double>& x, std::vector<std::complex<double> >& m, int nTheta, std::vector<double>& Theta, double *Qext, double *Qsca, double *Qabs, double *Qbk, double *Qpr, double *g, double *Albedo, std::vector<std::complex<double> >& S1, std::vector<std::complex<double> >& S2) {
+    
+    if (x.size() != L || m.size() != L)
+        throw std::invalid_argument("Declared number of layers do not fit x and m!");
+    if (Theta.size() != nTheta)
+        throw std::invalid_argument("Declared number of sample for Theta is not correct!");
+    try {
+      MultiLayerMie multi_layer_mie;  
+      multi_layer_mie.SetLayersWidth(x);
+      multi_layer_mie.SetLayersIndex(m);
+      multi_layer_mie.SetAngles(Theta);
+    
+      multi_layer_mie.RunMieCalculations();
+      
+      *Qext = multi_layer_mie.GetQext();
+      *Qsca = multi_layer_mie.GetQsca();
+      *Qabs = multi_layer_mie.GetQabs();
+      *Qbk = multi_layer_mie.GetQbk();
+      *Qpr = multi_layer_mie.GetQpr();
+      *g = multi_layer_mie.GetAsymmetryFactor();
+      *Albedo = multi_layer_mie.GetAlbedo();
+      S1 = multi_layer_mie.GetS1();
+      S2 = multi_layer_mie.GetS2();
+    } catch(const std::invalid_argument& ia) {
+      // Will catch if  multi_layer_mie fails or other errors.
+      std::cerr << "Invalid argument: " << ia.what() << std::endl;
+      throw std::invalid_argument(ia);
+      return -1;
+    }  
+
+    return 0;
+  }
+
+
+//**********************************************************************************//
+// This function emulates a C call to calculate complex electric and magnetic field //
+// in the surroundings and inside (TODO) the particle.                              //
+//                                                                                  //
+// Input parameters:                                                                //
+//   L: Number of layers                                                            //
+//   pl: Index of PEC layer. If there is none just send 0 (zero)                    //
+//   x: Array containing the size parameters of the layers [0..L-1]                 //
+//   m: Array containing the relative refractive indexes of the layers [0..L-1]     //
+//   nmax: Maximum number of multipolar expansion terms to be used for the          //
+//         calculations. Only use it if you know what you are doing, otherwise      //
+//         set this parameter to 0 (zero) and the function will calculate it.       //
+//   ncoord: Number of coordinate points                                            //
+//   Coords: Array containing all coordinates where the complex electric and        //
+//           magnetic fields will be calculated                                     //
+//                                                                                  //
+// Output parameters:                                                               //
+//   E, H: Complex electric and magnetic field at the provided coordinates          //
+//                                                                                  //
+// Return value:                                                                    //
+//   Number of multipolar expansion terms used for the calculations                 //
+//**********************************************************************************//
+
+  int nField(const int L, const int pl, const std::vector<double>& x, const std::vector<std::complex<double> >& m, const int nmax, const int ncoord, const std::vector<double>& Xp_vec, const std::vector<double>& Yp_vec, const std::vector<double>& Zp_vec, std::vector<std::vector<std::complex<double> > >& E, std::vector<std::vector<std::complex<double> > >& H) {
+    if (x.size() != L || m.size() != L)
+      throw std::invalid_argument("Declared number of layers do not fit x and m!");
+    if (Xp_vec.size() != ncoord || Yp_vec.size() != ncoord || Zp_vec.size() != ncoord
+        || E.size() != ncoord || H.size() != ncoord)
+      throw std::invalid_argument("Declared number of coords do not fit Xp, Yp, Zp, E, or H!");
+    for (auto f:E)
+      if (f.size() != 3)
+        throw std::invalid_argument("Field E is not 3D!");
+    for (auto f:H)
+      if (f.size() != 3)
+        throw std::invalid_argument("Field H is not 3D!");
+    try {
+      MultiLayerMie multi_layer_mie;  
+      //multi_layer_mie.SetPEC(pl);
+      multi_layer_mie.SetLayersWidth(x);
+      multi_layer_mie.SetLayersIndex(m);      
+      multi_layer_mie.SetFieldCoords({Xp_vec, Yp_vec, Zp_vec});
+      multi_layer_mie.RunFieldCalculations();
+      E = multi_layer_mie.GetFieldE();
+      H = multi_layer_mie.GetFieldH();
+      //multi_layer_mie.GetFailed();
+    } catch(const std::invalid_argument& ia) {
+      // Will catch if  multi_layer_mie fails or other errors.
+      std::cerr << "Invalid argument: " << ia.what() << std::endl;
+      throw std::invalid_argument(ia);
+      return - 1;
+    }  
+
+    return 0;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated Qext                                     //
+  // ********************************************************************** //
+
+  double MultiLayerMie::GetQext() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return Qext_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated Qabs                                     //
+  // ********************************************************************** //
+
+  double MultiLayerMie::GetQabs() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return Qabs_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated Qsca                                     //
+  // ********************************************************************** //
+
+  double MultiLayerMie::GetQsca() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return Qsca_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated Qbk                                      //
+  // ********************************************************************** //
+
+  double MultiLayerMie::GetQbk() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return Qbk_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated Qpr                                      //
+  // ********************************************************************** //
+
+  double MultiLayerMie::GetQpr() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return Qpr_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated assymetry factor                         //
+  // ********************************************************************** //
+
+  double MultiLayerMie::GetAsymmetryFactor() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return asymmetry_factor_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated Albedo                                   //
+  // ********************************************************************** //
+
+  double MultiLayerMie::GetAlbedo() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return albedo_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated S1                                       //
+  // ********************************************************************** //
+
+  std::vector<std::complex<double> > MultiLayerMie::GetS1() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return S1_;
+  }
+
+
+  // ********************************************************************** //
+  // Returns previously calculated S2                                       //
+  // ********************************************************************** //
+
+  std::vector<std::complex<double> > MultiLayerMie::GetS2() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    return S2_;
+  }
+
+
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::AddTargetLayer(double width, std::complex<double> layer_index) {
+    isMieCalculated_ = false;
+    if (width <= 0)
+      throw std::invalid_argument("Layer width should be positive!");
+    target_width_.push_back(width);
+    target_index_.push_back(layer_index);
+  }  // end of void  MultiLayerMie::AddTargetLayer(...)  
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetTargetPEC(double radius) {
+    isMieCalculated_ = false;
+    if (target_width_.size() != 0 || target_index_.size() != 0)
+      throw std::invalid_argument("Error! Define PEC target radius before any other layers!");
+    // Add layer of any index...
+    AddTargetLayer(radius, std::complex<double>(0.0, 0.0));
+    // ... and mark it as PEC
+    SetPEC(0.0);
+  }
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetCoatingIndex(std::vector<std::complex<double> > index) {
+    isMieCalculated_ = false;
+    index_.clear();
+    for (auto value : index) index_.push_back(value);
+  }  // end of void MultiLayerMie::SetCoatingIndex(std::vector<complex> index);  
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetAngles(const std::vector<double>& angles) {
+    isMieCalculated_ = false;
+    theta_ = angles;
+    // theta_.clear();
+    // for (auto value : angles) theta_.push_back(value);
+  }  // end of SetAngles()
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetCoatingWidth(std::vector<double> width) {
+    isMieCalculated_ = false;
+    width_.clear();
+    for (auto w : width)
+      if (w <= 0)
+        throw std::invalid_argument("Coating width should be positive!");
+      else width_.push_back(w);
+  }
+  // end of void MultiLayerMie::SetCoatingWidth(...);
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetLayersWidth(const std::vector<double>& size_parameter) {
+    isMieCalculated_ = false;
+    size_parameter_.clear();
+    double prev_size_parameter = 0.0;
+    for (auto layer_size_parameter : size_parameter) {
+      if (layer_size_parameter <= 0.0)
+        throw std::invalid_argument("Size parameter should be positive!");
+      if (prev_size_parameter > layer_size_parameter) 
+        throw std::invalid_argument
+          ("Size parameter for next layer should be larger than the previous one!");
+      prev_size_parameter = layer_size_parameter;
+      size_parameter_.push_back(layer_size_parameter);
+    }
+  }
+  // end of void MultiLayerMie::SetLayersWidth(...);
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetLayersIndex(const std::vector< std::complex<double> >& index) {
+    isMieCalculated_ = false;
+    //index_.clear();
+    index_ = index;
+    // for (auto value : index) index_.push_back(value);
+  }  // end of void MultiLayerMie::SetLayersIndex(...);  
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetFieldCoords(const std::vector< std::vector<double> >& coords_sp) {
+    if (coords_sp.size() != 3)
+      throw std::invalid_argument("Error! Wrong dimension of field monitor points!");
+    if (coords_sp[0].size() != coords_sp[1].size() || coords_sp[0].size() != coords_sp[2].size())
+      throw std::invalid_argument("Error! Missing coordinates for field monitor points!");
+    coords_sp_ = coords_sp;
+    // for (int i = 0; i < coords_sp_[0].size(); ++i) {
+    //   printf("%g, %g, %g\n", coords_sp_[0][i], coords_sp_[1][i], coords_sp_[2][i]);
+    // }
+  }  // end of void MultiLayerMie::SetFieldCoords(...)
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::SetPEC(int layer_position) {
+    isMieCalculated_ = false;
+    if (layer_position < 0)
+      throw std::invalid_argument("Error! Layers are numbered from 0!");
+    PEC_layer_position_ = layer_position;
+  }
+
+
+  // ********************************************************************** //
+  // Set maximun number of terms to be used                                 //
+  // ********************************************************************** //
+
+  void MultiLayerMie::SetMaxTerms(int nmax) {    
+    isMieCalculated_ = false;
+    nmax_preset_ = nmax;
+    //debug
+    printf("Setting max terms: %d\n", nmax_preset_);
+  }
+
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::GenerateIndex() {
+    isMieCalculated_ = false;
+    index_.clear();
+    for (auto index : target_index_) index_.push_back(index);
+    for (auto index : index_) index_.push_back(index);
+  }  // end of void MultiLayerMie::GenerateIndex();
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  double MultiLayerMie::GetTotalRadius() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("You should run calculations before result request!");
+    if (total_radius_ == 0) GenerateSizeParameter();
+    return total_radius_;      
+  }  // end of double MultiLayerMie::GetTotalRadius();
+
+
+  // ********************************************************************** //
+  // Clear layer information                                                //
+  // ********************************************************************** //
+
+  void MultiLayerMie::ClearLayers() {
+    isMieCalculated_ = false;
+    width_.clear();
+    index_.clear();
+  }
+
+
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  //                         Computational core
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+
+
+  // ********************************************************************** //
+  // Calculate Nstop - equation (17)                                        //
+  // ********************************************************************** //
+
+  void MultiLayerMie::Nstop() {
+    const double& xL = size_parameter_.back();
+    if (xL <= 8) {
+      nmax_ = round(xL + 4.0*pow(xL, 1.0/3.0) + 1);
+    } else if (xL <= 4200) {
+      nmax_ = round(xL + 4.05*pow(xL, 1.0/3.0) + 2);
+    } else {
+      nmax_ = round(xL + 4.0*pow(xL, 1.0/3.0) + 2);
+    }    
+  }
+
+
+  // ********************************************************************** //
+  // Maximum number of terms required for the calculation                   //
+  // ********************************************************************** //
+
+  void MultiLayerMie::Nmax(int first_layer) {
+    int ri, riM1;
+    const std::vector<double>& x = size_parameter_;
+    const std::vector<std::complex<double> >& m = index_;
+    Nstop();  // Set initial nmax_ value
+    for (int i = first_layer; i < x.size(); i++) {
+      if (i > PEC_layer_position_) 
+        ri = round(std::abs(x[i]*m[i]));
+      else 
+        ri = 0;      
+      nmax_ = std::max(nmax_, ri);
+      // first layer is pec, if pec is present
+      if ((i > first_layer) && ((i - 1) > PEC_layer_position_)) 
+        riM1 = round(std::abs(x[i - 1]* m[i]));
+      else 
+        riM1 = 0;      
+      nmax_ = std::max(nmax_, riM1);
+    }
+    nmax_ += 15;  // Final nmax_ value
+  }
+
+
+  //**********************************************************************************//
+  // This function calculates the spherical Bessel (jn) and Hankel (h1n) functions    //
+  // and their derivatives for a given complex value z. See pag. 87 B&H.              //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   z: Real argument to evaluate jn and h1n                                        //
+  //   nmax_: Maximum number of terms to calculate jn and h1n                         //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   jn, h1n: Spherical Bessel and Hankel functions                                 //
+  //   jnp, h1np: Derivatives of the spherical Bessel and Hankel functions            //
+  //                                                                                  //
+  // The implementation follows the algorithm by I.J. Thompson and A.R. Barnett,      //
+  // Comp. Phys. Comm. 47 (1987) 245-257.                                             //
+  //                                                                                  //
+  // Complex spherical Bessel functions from n=0..nmax_-1 for z in the upper half     //
+  // plane (Im(z) > -3).                                                              //
+  //                                                                                  //
+  //     j[n]   = j/n(z)                Regular solution: j[0]=sin(z)/z               //
+  //     j'[n]  = d[j/n(z)]/dz                                                        //
+  //     h1[n]  = h[0]/n(z)             Irregular Hankel function:                    //
+  //     h1'[n] = d[h[0]/n(z)]/dz                h1[0] = j0(z) + i*y0(z)              //
+  //                                                   = (sin(z)-i*cos(z))/z          //
+  //                                                   = -i*exp(i*z)/z                //
+  // Using complex CF1, and trigonometric forms for n=0 solutions.                    //
+  //**********************************************************************************//
+
+  void MultiLayerMie::sbesjh(std::complex<double> z,
+                             std::vector<std::complex<double> >& jn,
+                             std::vector<std::complex<double> >& jnp,
+                             std::vector<std::complex<double> >& h1n,
+                             std::vector<std::complex<double> >& h1np) {
+    const int limit = 20000;
+    const double accur = 1.0e-12;
+    const double tm30 = 1e-30;
+
+    double absc;
+    std::complex<double> zi, w;
+    std::complex<double> pl, f, b, d, c, del, jn0, jndb, h1nldb, h1nbdb;
+
+    absc = std::abs(std::real(z)) + std::abs(std::imag(z));
+    if ((absc < accur) || (std::imag(z) < -3.0)) {
+      throw std::invalid_argument("TODO add error description for condition if ((absc < accur) || (std::imag(z) < -3.0))");
+    }
+
+    zi = 1.0/z;
+    w = zi + zi;
+
+    pl = double(nmax_)*zi;
+
+    f = pl + zi;
+    b = f + f + zi;
+    d = 0.0;
+    c = f;
+    for (int n = 0; n < limit; n++) {
+      d = b - d;
+      c = b - 1.0/c;
+
+      absc = std::abs(std::real(d)) + std::abs(std::imag(d));
+      if (absc < tm30) {
+        d = tm30;
+      }
+
+      absc = std::abs(std::real(c)) + std::abs(std::imag(c));
+      if (absc < tm30) {
+        c = tm30;
+      }
+
+      d = 1.0/d;
+      del = d*c;
+      f = f*del;
+      b += w;
+
+      absc = std::abs(std::real(del - 1.0)) + std::abs(std::imag(del - 1.0));
+
+      if (absc < accur) {
+        // We have obtained the desired accuracy
+        break;
+      }
+    }
+
+    if (absc > accur) {
+      throw std::invalid_argument("We were not able to obtain the desired accuracy");
+    }
+
+    jn[nmax_ - 1] = tm30;
+    jnp[nmax_ - 1] = f*jn[nmax_ - 1];
+
+    // Downward recursion to n=0 (N.B.  Coulomb Functions)
+    for (int n = nmax_ - 2; n >= 0; n--) {
+      jn[n] = pl*jn[n + 1] + jnp[n + 1];
+      jnp[n] = pl*jn[n] - jn[n + 1];
+      pl = pl - zi;
+    }
+
+    // Calculate the n=0 Bessel Functions
+    jn0 = zi*std::sin(z);
+    h1n[0] = std::exp(std::complex<double>(0.0, 1.0)*z)*zi*(-std::complex<double>(0.0, 1.0));
+    h1np[0] = h1n[0]*(std::complex<double>(0.0, 1.0) - zi);
+
+    // Rescale j[n], j'[n], converting to spherical Bessel functions.
+    // Recur   h1[n], h1'[n] as spherical Bessel functions.
+    w = 1.0/jn[0];
+    pl = zi;
+    for (int n = 0; n < nmax_; n++) {
+      jn[n] = jn0*(w*jn[n]);
+      jnp[n] = jn0*(w*jnp[n]) - zi*jn[n];
+      if (n != 0) {
+        h1n[n] = (pl - zi)*h1n[n - 1] - h1np[n - 1];
+
+        // check if hankel is increasing (upward stable)
+        if (std::abs(h1n[n]) < std::abs(h1n[n - 1])) {
+          jndb = z;
+          h1nldb = h1n[n];
+          h1nbdb = h1n[n - 1];
+        }
+
+        pl += zi;
+
+        h1np[n] = -(pl*h1n[n]) + h1n[n - 1];
+      }
+    }
+  }
+
+
+  //**********************************************************************************//
+  // This function calculates the spherical Bessel functions (bj and by) and the      //
+  // logarithmic derivative (bd) for a given complex value z. See pag. 87 B&H.        //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   z: Complex argument to evaluate bj, by and bd                                  //
+  //   nmax_: Maximum number of terms to calculate bj, by and bd                       //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   bj, by: Spherical Bessel functions                                             //
+  //   bd: Logarithmic derivative                                                     //
+  //**********************************************************************************//
+
+  void MultiLayerMie::sphericalBessel(std::complex<double> z,
+                                      std::vector<std::complex<double> >& bj,
+                                      std::vector<std::complex<double> >& by,
+                                      std::vector<std::complex<double> >& bd) {
+    std::vector<std::complex<double> > jn(nmax_), jnp(nmax_), h1n(nmax_), h1np(nmax_);
+    sbesjh(z, jn, jnp, h1n, h1np);
+
+    for (int n = 0; n < nmax_; n++) {
+      bj[n] = jn[n];
+      by[n] = (h1n[n] - jn[n])/std::complex<double>(0.0, 1.0);
+      bd[n] = jnp[n]/jn[n] + 1.0/z;
+    }
+  }
+
+
+  // ********************************************************************** //
+  // Calculate an - equation (5)                                            //
+  // ********************************************************************** //
+
+  std::complex<double> MultiLayerMie::calc_an(int n, double XL, std::complex<double> Ha, std::complex<double> mL,
+                                              std::complex<double> PsiXL, std::complex<double> ZetaXL,
+                                              std::complex<double> PsiXLM1, std::complex<double> ZetaXLM1) {
+
+    std::complex<double> Num = (Ha/mL + n/XL)*PsiXL - PsiXLM1;
+    std::complex<double> Denom = (Ha/mL + n/XL)*ZetaXL - ZetaXLM1;
+
+    return Num/Denom;
+  }
+
+
+  // ********************************************************************** //
+  // Calculate bn - equation (6)                                            //
+  // ********************************************************************** //
+
+  std::complex<double> MultiLayerMie::calc_bn(int n, double XL, std::complex<double> Hb, std::complex<double> mL,
+                                              std::complex<double> PsiXL, std::complex<double> ZetaXL,
+                                              std::complex<double> PsiXLM1, std::complex<double> ZetaXLM1) {
+
+    std::complex<double> Num = (mL*Hb + n/XL)*PsiXL - PsiXLM1;
+    std::complex<double> Denom = (mL*Hb + n/XL)*ZetaXL - ZetaXLM1;
+
+    return Num/Denom;
+  }
+
+
+  // ********************************************************************** //
+  // Calculates S1 - equation (25a)                                         //
+  // ********************************************************************** //
+
+  std::complex<double> MultiLayerMie::calc_S1(int n, std::complex<double> an, std::complex<double> bn,
+                                              double Pi, double Tau) {
+    return double(n + n + 1)*(Pi*an + Tau*bn)/double(n*n + n);
+  }
+
+
+  // ********************************************************************** //
+  // Calculates S2 - equation (25b) (it's the same as (25a), just switches  //
+  // Pi and Tau)                                                            //
+  // ********************************************************************** //
+
+  std::complex<double> MultiLayerMie::calc_S2(int n, std::complex<double> an, std::complex<double> bn,
+                                              double Pi, double Tau) {
+    return calc_S1(n, an, bn, Tau, Pi);
+  }
+
+
+  //**********************************************************************************//
+  // This function calculates the Riccati-Bessel functions (Psi and Zeta) for a       //
+  // real argument (x).                                                               //
+  // Equations (20a) - (21b)                                                          //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   x: Real argument to evaluate Psi and Zeta                                      //
+  //   nmax: Maximum number of terms to calculate Psi and Zeta                        //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   Psi, Zeta: Riccati-Bessel functions                                            //
+  //**********************************************************************************//
+
+  void MultiLayerMie::calcPsiZeta(std::complex<double> z,
+                                  std::vector<std::complex<double> > D1,
+                                  std::vector<std::complex<double> > D3,
+                                  std::vector<std::complex<double> >& Psi,
+                                  std::vector<std::complex<double> >& Zeta) {
+
+    //Upward recurrence for Psi and Zeta - equations (20a) - (21b)
+    std::complex<double> c_i(0.0, 1.0);
+    Psi[0] = std::sin(z);
+    Zeta[0] = std::sin(z) - c_i*std::cos(z);
+    for (int n = 1; n <= nmax_; n++) {
+      Psi[n] = Psi[n - 1]*(static_cast<double>(n)/z - D1[n - 1]);
+      Zeta[n] = Zeta[n - 1]*(static_cast<double>(n)/z - D3[n - 1]);
+    }
+
+  }
+
+
+  //**********************************************************************************//
+  // This function calculates the logarithmic derivatives of the Riccati-Bessel       //
+  // functions (D1 and D3) for a complex argument (z).                                //
+  // Equations (16a), (16b) and (18a) - (18d)                                         //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   z: Complex argument to evaluate D1 and D3                                      //
+  //   nmax_: Maximum number of terms to calculate D1 and D3                          //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   D1, D3: Logarithmic derivatives of the Riccati-Bessel functions                //
+  //**********************************************************************************//
+
+  void MultiLayerMie::calcD1D3(const std::complex<double> z,
+                               std::vector<std::complex<double> >& D1,
+                               std::vector<std::complex<double> >& D3) {
+
+    // Downward recurrence for D1 - equations (16a) and (16b)
+    D1[nmax_] = std::complex<double>(0.0, 0.0);
+    const std::complex<double> zinv = std::complex<double>(1.0, 0.0)/z;
+
+    for (int n = nmax_; n > 0; n--) {
+      D1[n - 1] = double(n)*zinv - 1.0/(D1[n] + double(n)*zinv);
+    }
+
+    if (std::abs(D1[0]) > 100000.0)
+      throw std::invalid_argument("Unstable D1! Please, try to change input parameters!\n");
+
+    // Upward recurrence for PsiZeta and D3 - equations (18a) - (18d)
+    PsiZeta_[0] = 0.5*(1.0 - std::complex<double>(std::cos(2.0*z.real()), std::sin(2.0*z.real()))
+                       *std::exp(-2.0*z.imag()));
+    D3[0] = std::complex<double>(0.0, 1.0);
+    for (int n = 1; n <= nmax_; n++) {
+      PsiZeta_[n] = PsiZeta_[n - 1]*(static_cast<double>(n)*zinv - D1[n - 1])
+        *(static_cast<double>(n)*zinv- D3[n - 1]);
+      D3[n] = D1[n] + std::complex<double>(0.0, 1.0)/PsiZeta_[n];
+    }
+  }
+
+
+  //**********************************************************************************//
+  // This function calculates Pi and Tau for all values of Theta.                     //
+  // Equations (26a) - (26c)                                                          //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   nmax_: Maximum number of terms to calculate Pi and Tau                         //
+  //   nTheta: Number of scattering angles                                            //
+  //   Theta: Array containing all the scattering angles where the scattering         //
+  //          amplitudes will be calculated                                           //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   Pi, Tau: Angular functions Pi and Tau, as defined in equations (26a) - (26c)   //
+  //**********************************************************************************//
+
+  void MultiLayerMie::calcSinglePiTau(const double& costheta, std::vector<double>& Pi,
+                                      std::vector<double>& Tau) {
+
+    //****************************************************//
+    // Equations (26a) - (26c)                            //
+    //****************************************************//
+    for (int n = 0; n < nmax_; n++) {
+      if (n == 0) {
+        // Initialize Pi and Tau
+        Pi[n] = 1.0;
+        Tau[n] = (n + 1)*costheta; 
+      } else {
+        // Calculate the actual values
+        Pi[n] = ((n == 1) ? ((n + n + 1)*costheta*Pi[n - 1]/n)
+                 : (((n + n + 1)*costheta*Pi[n - 1]
+                     - (n + 1)*Pi[n - 2])/n));
+        Tau[n] = (n + 1)*costheta*Pi[n] - (n + 2)*Pi[n - 1];
+      }
+    }
+  }  // end of void MultiLayerMie::calcPiTau(...)
+
+
+  void MultiLayerMie::calcAllPiTau(std::vector< std::vector<double> >& Pi,
+                                   std::vector< std::vector<double> >& Tau) {
+    std::vector<double> costheta(theta_.size(), 0.0);
+    for (int t = 0; t < theta_.size(); t++) {
+      costheta[t] = std::cos(theta_[t]);
+    }
+    // Do not join upper and lower 'for' to a single one!  It will slow
+    // down the code!!! (For about 0.5-2.0% of runtime, it is probably
+    // due to increased cache missing rate originated from the
+    // recurrence in calcPiTau...)
+    for (int t = 0; t < theta_.size(); t++) {
+      calcSinglePiTau(costheta[t], Pi[t], Tau[t]);
+      //calcSinglePiTau(std::cos(theta_[t]), Pi[t], Tau[t]); // It is slow!!
+    }
+  }  // end of void MultiLayerMie::calcAllPiTau(...)
+
+  //**********************************************************************************//
+  // This function calculates the scattering coefficients required to calculate       //
+  // both the near- and far-field parameters.                                         //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   L: Number of layers                                                            //
+  //   pl: Index of PEC layer. If there is none just send -1                          //
+  //   x: Array containing the size parameters of the layers [0..L-1]                 //
+  //   m: Array containing the relative refractive indexes of the layers [0..L-1]     //
+  //   nmax: Maximum number of multipolar expansion terms to be used for the          //
+  //         calculations. Only use it if you know what you are doing, otherwise      //
+  //         set this parameter to -1 and the function will calculate it.             //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   an, bn: Complex scattering amplitudes                                          //
+  //                                                                                  //
+  // Return value:                                                                    //
+  //   Number of multipolar expansion terms used for the calculations                 //
+  //**********************************************************************************//
+  void MultiLayerMie::ExtScattCoeffs(std::vector<std::complex<double> >& an,
+                                  std::vector<std::complex<double> >& bn) {
+    const std::vector<double>& x = size_parameter_;
+    const std::vector<std::complex<double> >& m = index_;
+    const int& pl = PEC_layer_position_;
+    const int L = index_.size();
+    //************************************************************************//
+    // Calculate the index of the first layer. It can be either 0 (default)   //
+    // or the index of the outermost PEC layer. In the latter case all layers //
+    // below the PEC are discarded.                                           //
+    // ***********************************************************************//
+    // TODO, is it possible for PEC to have a zero index? If yes than
+    // is should be:
+    // int fl = (pl > - 1) ? pl : 0;
+    // This will give the same result, however, it corresponds the
+    // logic - if there is PEC, than first layer is PEC.
+    // Well, I followed the logic: First layer is always zero unless it has 
+    // an upper PEC layer.
+    int fl = (pl > 0) ? pl : 0;
+    if (nmax_ <= 0) Nmax(fl);
+
+    std::complex<double> z1, z2;
+    //**************************************************************************//
+    // Note that since Fri, Nov 14, 2014 all arrays start from 0 (zero), which  //
+    // means that index = layer number - 1 or index = n - 1. The only exception //
+    // are the arrays for representing D1, D3 and Q because they need a value   //
+    // for the index 0 (zero), hence it is important to consider this shift     //
+    // between different arrays. The change was done to optimize memory usage.  //
+    //**************************************************************************//
+    // Allocate memory to the arrays
+    std::vector<std::complex<double> > D1_mlxl(nmax_ + 1), D1_mlxlM1(nmax_ + 1),
+                                       D3_mlxl(nmax_ + 1), D3_mlxlM1(nmax_ + 1);
+
+    std::vector<std::vector<std::complex<double> > > Q(L), Ha(L), Hb(L);
+
+    for (int l = 0; l < L; l++) {
+      Q[l].resize(nmax_ + 1);
+      Ha[l].resize(nmax_);
+      Hb[l].resize(nmax_);
+    }
+
+    an.resize(nmax_);
+    bn.resize(nmax_);
+    PsiZeta_.resize(nmax_ + 1);
+
+    std::vector<std::complex<double> > D1XL(nmax_ + 1), D3XL(nmax_ + 1), 
+                                       PsiXL(nmax_ + 1), ZetaXL(nmax_ + 1);
+
+    //*************************************************//
+    // Calculate D1 and D3 for z1 in the first layer   //
+    //*************************************************//
+    if (fl == pl) {  // PEC layer
+      for (int n = 0; n <= nmax_; n++) {
+        D1_mlxl[n] = std::complex<double>(0.0, - 1.0);
+        D3_mlxl[n] = std::complex<double>(0.0, 1.0);
+      }
+    } else { // Regular layer
+      z1 = x[fl]* m[fl];
+      // Calculate D1 and D3
+      calcD1D3(z1, D1_mlxl, D3_mlxl);
+    }
+    // do { \
+    //   ++iformat;\
+    //   if (iformat%5 == 0) printf("%24.16e",z1.real());
+    // } while (false);
+    //******************************************************************//
+    // Calculate Ha and Hb in the first layer - equations (7a) and (8a) //
+    //******************************************************************//
+    for (int n = 0; n < nmax_; n++) {
+      Ha[fl][n] = D1_mlxl[n + 1];
+      Hb[fl][n] = D1_mlxl[n + 1];
+    }
+    //*****************************************************//
+    // Iteration from the second layer to the last one (L) //
+    //*****************************************************//
+    std::complex<double> Temp, Num, Denom;
+    std::complex<double> G1, G2;
+    for (int l = fl + 1; l < L; l++) {
+      //************************************************************//
+      //Calculate D1 and D3 for z1 and z2 in the layers fl + 1..L     //
+      //************************************************************//
+      z1 = x[l]*m[l];
+      z2 = x[l - 1]*m[l];
+      //Calculate D1 and D3 for z1
+      calcD1D3(z1, D1_mlxl, D3_mlxl);
+      //Calculate D1 and D3 for z2
+      calcD1D3(z2, D1_mlxlM1, D3_mlxlM1);
+      // prn(z1.real());
+      // for (auto i : D1_mlxl) { prn(i.real());
+      //   // prn(i.imag());
+      //         } printf("\n");
+
+      //*********************************************//
+      //Calculate Q, Ha and Hb in the layers fl + 1..L //
+      //*********************************************//
+      // Upward recurrence for Q - equations (19a) and (19b)
+      Num = std::exp(-2.0*(z1.imag() - z2.imag()))
+       *std::complex<double>(std::cos(-2.0*z2.real()) - std::exp(-2.0*z2.imag()), std::sin(-2.0*z2.real()));
+      Denom = std::complex<double>(std::cos(-2.0*z1.real()) - std::exp(-2.0*z1.imag()), std::sin(-2.0*z1.real()));
+      Q[l][0] = Num/Denom;
+      for (int n = 1; n <= nmax_; n++) {
+        Num = (z1*D1_mlxl[n] + double(n))*(double(n) - z1*D3_mlxl[n - 1]);
+        Denom = (z2*D1_mlxlM1[n] + double(n))*(double(n) - z2*D3_mlxlM1[n - 1]);
+        Q[l][n] = ((pow2(x[l - 1]/x[l])* Q[l][n - 1])*Num)/Denom;
+      }
+      // Upward recurrence for Ha and Hb - equations (7b), (8b) and (12) - (15)
+      for (int n = 1; n <= nmax_; n++) {
+        //Ha
+        if ((l - 1) == pl) { // The layer below the current one is a PEC layer
+          G1 = -D1_mlxlM1[n];
+          G2 = -D3_mlxlM1[n];
+        } else {
+          G1 = (m[l]*Ha[l - 1][n - 1]) - (m[l - 1]*D1_mlxlM1[n]);
+          G2 = (m[l]*Ha[l - 1][n - 1]) - (m[l - 1]*D3_mlxlM1[n]);
+        }  // end of if PEC
+        Temp = Q[l][n]*G1;
+        Num = (G2*D1_mlxl[n]) - (Temp*D3_mlxl[n]);
+        Denom = G2 - Temp;
+        Ha[l][n - 1] = Num/Denom;
+        //Hb
+        if ((l - 1) == pl) { // The layer below the current one is a PEC layer
+          G1 = Hb[l - 1][n - 1];
+          G2 = Hb[l - 1][n - 1];
+        } else {
+          G1 = (m[l - 1]*Hb[l - 1][n - 1]) - (m[l]*D1_mlxlM1[n]);
+          G2 = (m[l - 1]*Hb[l - 1][n - 1]) - (m[l]*D3_mlxlM1[n]);
+        }  // end of if PEC
+
+        Temp = Q[l][n]*G1;
+        Num = (G2*D1_mlxl[n]) - (Temp* D3_mlxl[n]);
+        Denom = (G2- Temp);
+        Hb[l][n - 1] = (Num/ Denom);
+      }  // end of for Ha and Hb terms
+    }  // end of for layers iteration
+    //**************************************//
+    //Calculate D1, D3, Psi and Zeta for XL //
+    //**************************************//
+    // Calculate D1XL and D3XL
+    calcD1D3(x[L - 1], D1XL, D3XL);
+    //printf("%5.20f\n",Ha[L - 1][0].real());
+    // Calculate PsiXL and ZetaXL
+    calcPsiZeta(x[L - 1], D1XL, D3XL, PsiXL, ZetaXL);
+    //*********************************************************************//
+    // Finally, we calculate the scattering coefficients (an and bn) and   //
+    // the angular functions (Pi and Tau). Note that for these arrays the  //
+    // first layer is 0 (zero), in future versions all arrays will follow  //
+    // this convention to save memory. (13 Nov, 2014)                      //
+    //*********************************************************************//
+    for (int n = 0; n < nmax_; n++) {
+      //********************************************************************//
+      //Expressions for calculating an and bn coefficients are not valid if //
+      //there is only one PEC layer (ie, for a simple PEC sphere).          //
+      //********************************************************************//
+      if (pl < (L - 1)) {
+        an[n] = calc_an(n + 1, x[L - 1], Ha[L - 1][n], m[L - 1], PsiXL[n + 1], ZetaXL[n + 1], PsiXL[n], ZetaXL[n]);
+        bn[n] = calc_bn(n + 1, x[L - 1], Hb[L - 1][n], m[L - 1], PsiXL[n + 1], ZetaXL[n + 1], PsiXL[n], ZetaXL[n]);
+      } else {
+        an[n] = calc_an(n + 1, x[L - 1], std::complex<double>(0.0, 0.0), std::complex<double>(1.0, 0.0), PsiXL[n + 1], ZetaXL[n + 1], PsiXL[n], ZetaXL[n]);
+        bn[n] = PsiXL[n + 1]/ZetaXL[n + 1];
+      }
+    }  // end of for an and bn terms
+  }  // end of void MultiLayerMie::ExtScattCoeffs(...)
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::InitMieCalculations() {
+    isMieCalculated_ = false;
+    // Initialize the scattering parameters
+    Qext_ = 0;
+    Qsca_ = 0;
+    Qabs_ = 0;
+    Qbk_ = 0;
+    Qpr_ = 0;
+    asymmetry_factor_ = 0;
+    albedo_ = 0;
+    Qsca_ch_.clear();
+    Qext_ch_.clear();
+    Qabs_ch_.clear();
+    Qbk_ch_.clear();
+    Qpr_ch_.clear();
+    Qsca_ch_.resize(nmax_ - 1);
+    Qext_ch_.resize(nmax_ - 1);
+    Qabs_ch_.resize(nmax_ - 1);
+    Qbk_ch_.resize(nmax_ - 1);
+    Qpr_ch_.resize(nmax_ - 1);
+    Qsca_ch_norm_.resize(nmax_ - 1);
+    Qext_ch_norm_.resize(nmax_ - 1);
+    Qabs_ch_norm_.resize(nmax_ - 1);
+    Qbk_ch_norm_.resize(nmax_ - 1);
+    Qpr_ch_norm_.resize(nmax_ - 1);
+    // Initialize the scattering amplitudes
+    std::vector<std::complex<double> > tmp1(theta_.size(),std::complex<double>(0.0, 0.0));
+    S1_.swap(tmp1);
+    S2_ = S1_;
+  }
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::ConvertToSP() {
+    isMieCalculated_ = false;
+    if (target_width_.size() + width_.size() == 0)
+      return;  // Nothing to convert, we suppose that SP was set directly
+    GenerateSizeParameter();
+    GenerateIndex();
+    if (size_parameter_.size() != index_.size())
+      throw std::invalid_argument("Ivalid conversion of width to size parameter units!/n");
+  }
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  //**********************************************************************************//
+  // This function calculates the actual scattering parameters and amplitudes         //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   L: Number of layers                                                            //
+  //   pl: Index of PEC layer. If there is none just send -1                          //
+  //   x: Array containing the size parameters of the layers [0..L-1]                 //
+  //   m: Array containing the relative refractive indexes of the layers [0..L-1]     //
+  //   nTheta: Number of scattering angles                                            //
+  //   Theta: Array containing all the scattering angles where the scattering         //
+  //          amplitudes will be calculated                                           //
+  //   nmax_: Maximum number of multipolar expansion terms to be used for the         //
+  //         calculations. Only use it if you know what you are doing, otherwise      //
+  //         set this parameter to -1 and the function will calculate it              //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   Qext: Efficiency factor for extinction                                         //
+  //   Qsca: Efficiency factor for scattering                                         //
+  //   Qabs: Efficiency factor for absorption (Qabs = Qext - Qsca)                    //
+  //   Qbk: Efficiency factor for backscattering                                      //
+  //   Qpr: Efficiency factor for the radiation pressure                              //
+  //   g: Asymmetry factor (g = (Qext-Qpr)/Qsca)                                      //
+  //   Albedo: Single scattering albedo (Albedo = Qsca/Qext)                          //
+  //   S1, S2: Complex scattering amplitudes                                          //
+  //                                                                                  //
+  // Return value:                                                                    //
+  //   Number of multipolar expansion terms used for the calculations                 //
+  //**********************************************************************************//
+  void MultiLayerMie::RunMieCalculations() {
+    isMieCalculated_ = false;
+    ConvertToSP();
+    nmax_ = nmax_preset_;
+    if (size_parameter_.size() != index_.size())
+      throw std::invalid_argument("Each size parameter should have only one index!");
+    if (size_parameter_.size() == 0)
+      throw std::invalid_argument("Initialize model first!");
+    const std::vector<double>& x = size_parameter_;
+    // Calculate scattering coefficients
+    ExtScattCoeffs(an_, bn_);
+
+    // std::vector< std::vector<double> > Pi(nmax_), Tau(nmax_);
+    std::vector< std::vector<double> > Pi, Tau;
+    Pi.resize(theta_.size());
+    Tau.resize(theta_.size());
+    for (int i =0; i< theta_.size(); ++i) {
+      Pi[i].resize(nmax_);
+      Tau[i].resize(nmax_);
+    }
+    calcAllPiTau(Pi, Tau);    
+    InitMieCalculations(); //
+    std::complex<double> Qbktmp(0.0, 0.0);
+    std::vector< std::complex<double> > Qbktmp_ch(nmax_ - 1, Qbktmp);
+    // By using downward recurrence we avoid loss of precision due to float rounding errors
+    // See: https://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html
+    //      http://en.wikipedia.org/wiki/Loss_of_significance
+    for (int i = nmax_ - 2; i >= 0; i--) {
+      const int n = i + 1;
+      // Equation (27)
+      Qext_ch_norm_[i] = (an_[i].real() + bn_[i].real());
+      Qext_ch_[i] = (n + n + 1.0)*Qext_ch_norm_[i];
+      //Qext_ch_[i] = (n + n + 1)*(an_[i].real() + bn_[i].real());
+      Qext_ += Qext_ch_[i];
+      // Equation (28)
+      Qsca_ch_norm_[i] = (an_[i].real()*an_[i].real() + an_[i].imag()*an_[i].imag()
+                          + bn_[i].real()*bn_[i].real() + bn_[i].imag()*bn_[i].imag());
+      Qsca_ch_[i] = (n + n + 1.0)*Qsca_ch_norm_[i];
+      Qsca_ += Qsca_ch_[i];
+      // Qsca_ch_[i] += (n + n + 1)*(an_[i].real()*an_[i].real() + an_[i].imag()*an_[i].imag()
+      //                             + bn_[i].real()*bn_[i].real() + bn_[i].imag()*bn_[i].imag());
+
+      // Equation (29) TODO We must check carefully this equation. If we
+      // remove the typecast to double then the result changes. Which is
+      // the correct one??? Ovidio (2014/12/10) With cast ratio will
+      // give double, without cast (n + n + 1)/(n*(n + 1)) will be
+      // rounded to integer. Tig (2015/02/24)
+      Qpr_ch_[i]=((n*(n + 2)/(n + 1))*((an_[i]*std::conj(an_[n]) + bn_[i]*std::conj(bn_[n])).real())
+               + ((double)(n + n + 1)/(n*(n + 1)))*(an_[i]*std::conj(bn_[i])).real());
+      Qpr_ += Qpr_ch_[i];
+      // Equation (33)      
+      Qbktmp_ch[i] = (double)(n + n + 1)*(1 - 2*(n % 2))*(an_[i]- bn_[i]);
+      Qbktmp += Qbktmp_ch[i];
+      // Calculate the scattering amplitudes (S1 and S2)    //
+      // Equations (25a) - (25b)                            //
+      for (int t = 0; t < theta_.size(); t++) {
+        S1_[t] += calc_S1(n, an_[i], bn_[i], Pi[t][i], Tau[t][i]);
+        S2_[t] += calc_S2(n, an_[i], bn_[i], Pi[t][i], Tau[t][i]);
+      }
+    }
+    double x2 = pow2(x.back());
+    Qext_ = 2.0*(Qext_)/x2;                                 // Equation (27)
+    for (double& Q : Qext_ch_) Q = 2.0*Q/x2;
+    Qsca_ = 2.0*(Qsca_)/x2;                                 // Equation (28)
+    for (double& Q : Qsca_ch_) Q = 2.0*Q/x2;
+    //for (double& Q : Qsca_ch_norm_) Q = 2.0*Q/x2;
+    Qpr_ = Qext_ - 4.0*(Qpr_)/x2;                           // Equation (29)
+    for (int i = 0; i < nmax_ - 1; ++i) Qpr_ch_[i] = Qext_ch_[i] - 4.0*Qpr_ch_[i]/x2;
+
+    Qabs_ = Qext_ - Qsca_;                                // Equation (30)
+    for (int i = 0; i < nmax_ - 1; ++i) {
+      Qabs_ch_[i] = Qext_ch_[i] - Qsca_ch_[i];
+      Qabs_ch_norm_[i] = Qext_ch_norm_[i] - Qsca_ch_norm_[i];
+    }
+    
+    albedo_ = Qsca_/Qext_;                              // Equation (31)
+    asymmetry_factor_ = (Qext_ - Qpr_)/Qsca_;                          // Equation (32)
+
+    Qbk_ = (Qbktmp.real()*Qbktmp.real() + Qbktmp.imag()*Qbktmp.imag())/x2;    // Equation (33)
+
+    isMieCalculated_ = true;
+    nmax_used_ = nmax_;
+    // printf("Run Mie result: Qext = %g, Qsca = %g, Qabs = %g, Qbk = %g \n",
+    //            GetQext(), GetQsca(), GetQabs(), GetQbk());
+    //return nmax;
+  }
+  
+
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::IntScattCoeffsInit() {
+    const int L = index_.size();
+    // we need to fill
+    // std::vector< std::vector<std::complex<double> > > al_n_, bl_n_, cl_n_, dl_n_;
+    //     for n = [0..nmax_) and for l=[L..0)
+    // TODO: to decrease cache miss outer loop is with n and inner with reversed l
+    // at the moment outer is forward l and inner in n
+    al_n_.resize(L + 1);
+    bl_n_.resize(L + 1);
+    cl_n_.resize(L + 1);
+    dl_n_.resize(L + 1);
+    for (auto& element:al_n_) element.resize(nmax_);
+    for (auto& element:bl_n_) element.resize(nmax_);
+    for (auto& element:cl_n_) element.resize(nmax_);
+    for (auto& element:dl_n_) element.resize(nmax_);
+    std::complex<double> c_one(1.0, 0.0);
+    std::complex<double> c_zero(0.0, 0.0);
+    // Yang, paragraph under eq. A3
+    // a^(L + 1)_n = a_n, d^(L + 1) = 1 ...
+    for (int i = 0; i < nmax_; ++i) {
+      al_n_[L][i] = an_[i];
+      bl_n_[L][i] = bn_[i];
+      cl_n_[L][i] = c_one;
+      dl_n_[L][i] = c_one;
+      if (i < 3) printf(" (%g) ", std::abs(an_[i]));
+    }
+
+  }
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::IntScattCoeffs() {
+    if (!isMieCalculated_)
+      throw std::invalid_argument("(IntScattCoeffs) You should run calculations first!");
+    IntScattCoeffsInit();
+    const int L = index_.size();
+    std::vector<std::complex<double> > z(L), z1(L);
+    for (int i = 0; i < L - 1; ++i) {
+      z[i]  =size_parameter_[i]*index_[i];
+      z1[i]=size_parameter_[i]*index_[i + 1];
+    }
+    z[L - 1] = size_parameter_[L - 1]*index_[L - 1];
+    z1[L - 1] = size_parameter_[L - 1];
+    std::vector< std::vector<std::complex<double> > > D1z(L), D1z1(L), D3z(L), D3z1(L);
+    std::vector< std::vector<std::complex<double> > > Psiz(L), Psiz1(L), Zetaz(L), Zetaz1(L);
+    for (int l = 0; l < L; ++l) {
+      D1z[l].resize(nmax_ + 1);
+      D1z1[l].resize(nmax_ + 1);
+      D3z[l].resize(nmax_ + 1);
+      D3z1[l].resize(nmax_ + 1);
+      Psiz[l].resize(nmax_ + 1);
+      Psiz1[l].resize(nmax_ + 1);
+      Zetaz[l].resize(nmax_ + 1);
+      Zetaz1[l].resize(nmax_ + 1);
+    }
+    for (int l = 0; l < L; ++l) {
+      calcD1D3(z[l],D1z[l],D3z[l]);
+      calcD1D3(z1[l],D1z1[l],D3z1[l]);
+      calcPsiZeta(z[l],D1z[l],D3z[l], Psiz[l],Zetaz[l]);
+      calcPsiZeta(z1[l],D1z1[l],D3z1[l], Psiz1[l],Zetaz1[l]);
+    }
+    auto& m = index_;
+    std::vector< std::complex<double> > m1(L);
+    for (int l = 0; l < L - 1; ++l) m1[l] = m[l + 1];
+    m1[L - 1] = std::complex<double> (1.0, 0.0);
+    // for (auto zz : m) printf ("m[i]=%g \n\n ", zz.real());
+    for (int l = L - 1; l >= 0; --l) {
+      for (int n = 0; n < nmax_; ++n) {
+        // al_n
+        auto denom = m1[l]*Zetaz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        al_n_[l][n] = D1z[l][n + 1]*m1[l]*(al_n_[l + 1][n]*Zetaz1[l][n + 1] - dl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m[l]*(-D1z1[l][n + 1]*dl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*al_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        al_n_[l][n] /= denom;
+
+        // dl_n
+        denom = m1[l]*Psiz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        dl_n_[l][n] = D3z[l][n + 1]*m1[l]*(al_n_[l + 1][n]*Zetaz1[l][n + 1] - dl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m[l]*(-D1z1[l][n + 1]*dl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*al_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        dl_n_[l][n] /= denom;
+
+        // bl_n
+        denom = m1[l]*Zetaz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        bl_n_[l][n] = D1z[l][n + 1]*m[l]*(bl_n_[l + 1][n]*Zetaz1[l][n + 1] - cl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m1[l]*(-D1z1[l][n + 1]*cl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*bl_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        bl_n_[l][n] /= denom;
+
+        // cl_n
+        denom = m1[l]*Psiz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        cl_n_[l][n] = D3z[l][n + 1]*m[l]*(bl_n_[l + 1][n]*Zetaz1[l][n + 1] - cl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m1[l]*(-D1z1[l][n + 1]*cl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*bl_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        cl_n_[l][n] /= denom;   
+      }  // end of all n
+    }  // end of for all l
+
+    // Check the result and change  an__0 and bn__0 for exact zero
+    for (int n = 0; n < nmax_; ++n) {
+      if (std::abs(al_n_[0][n]) < 1e-10) al_n_[0][n] = 0.0;
+      else throw std::invalid_argument("Unstable calculation of a__0_n!");
+      if (std::abs(bl_n_[0][n]) < 1e-10) bl_n_[0][n] = 0.0;
+      else throw std::invalid_argument("Unstable calculation of b__0_n!");
+    }
+
+    // for (int l = 0; l < L; ++l) {
+    //   printf("l=%d --> ", l);
+    //   for (int n = 0; n < nmax_ + 1; ++n) {
+    //         if (n < 20) continue;
+    //         printf("n=%d --> D1zn=%g, D3zn=%g, D1zn=%g, D3zn=%g || ",
+    //                n,
+    //                D1z[l][n].real(), D3z[l][n].real(),
+    //                D1z1[l][n].real(), D3z1[l][n].real());
+    //   }
+    //   printf("\n\n");
+    // }
+    // for (int l = 0; l < L; ++l) {
+    //   printf("l=%d --> ", l);
+    //   for (int n = 0; n < nmax_ + 1; ++n) {
+    //         printf("n=%d --> D1zn=%g, D3zn=%g, D1zn=%g, D3zn=%g || ",
+    //                n,
+    //                D1z[l][n].real(), D3z[l][n].real(),
+    //                D1z1[l][n].real(), D3z1[l][n].real());
+    //   }
+    //   printf("\n\n");
+    // }
+    for (int i = 0; i < L + 1; ++i) {
+      printf("Layer =%d ---> ", i);
+      for (int n = 0; n < nmax_; ++n) {
+            //        if (n < 20) continue;
+            printf(" || n=%d --> a=%g,%g b=%g,%g c=%g,%g d=%g,%g",
+                   n,
+                   al_n_[i][n].real(), al_n_[i][n].imag(),
+                   bl_n_[i][n].real(), bl_n_[i][n].imag(),
+                   cl_n_[i][n].real(), cl_n_[i][n].imag(),
+                   dl_n_[i][n].real(), dl_n_[i][n].imag());
+      }
+      printf("\n\n");
+    }
+  }
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // external scattering field = incident + scattered
+  // BH p.92 (4.37), 94 (4.45), 95 (4.50)
+  // assume: medium is non-absorbing; refim = 0; Uabs = 0
+
+  void MultiLayerMie::fieldExt(const double Rho, const double Phi, const double Theta, const  std::vector<double>& Pi, const std::vector<double>& Tau, std::vector<std::complex<double> >& E, std::vector<std::complex<double> >& H)  {
+    
+    std::complex<double> c_zero(0.0, 0.0), c_i(0.0, 1.0);
+    std::vector<std::complex<double> > vm3o1n(3), vm3e1n(3), vn3o1n(3), vn3e1n(3);
+    std::vector<std::complex<double> > Ei(3,c_zero), Hi(3,c_zero), Es(3,c_zero), Hs(3,c_zero);
+    std::vector<std::complex<double> > bj(nmax_ + 1), by(nmax_ + 1), bd(nmax_ + 1);
+    // Calculate spherical Bessel and Hankel functions
+    printf("##########  layer OUT ############\n");
+    sphericalBessel(Rho,bj, by, bd);    
+    for (int n = 0; n < nmax_; n++) {
+      double rn = static_cast<double>(n + 1);
+      std::complex<double> zn = bj[n + 1] + c_i*by[n + 1];
+      // using BH 4.12 and 4.50
+      std::complex<double> xxip = Rho*(bj[n] + c_i*by[n]) - rn*zn;
+      
+      using std::sin;
+      using std::cos;
+      vm3o1n[0] = c_zero;
+      vm3o1n[1] = cos(Phi)*Pi[n]*zn;
+      vm3o1n[2] = -sin(Phi)*Tau[n]*zn;
+      vm3e1n[0] = c_zero;
+      vm3e1n[1] = -sin(Phi)*Pi[n]*zn;
+      vm3e1n[2] = -cos(Phi)*Tau[n]*zn;
+      vn3o1n[0] = sin(Phi)*rn*(rn + 1.0)*sin(Theta)*Pi[n]*zn/Rho;
+      vn3o1n[1] = sin(Phi)*Tau[n]*xxip/Rho;
+      vn3o1n[2] = cos(Phi)*Pi[n]*xxip/Rho;
+      vn3e1n[0] = cos(Phi)*rn*(rn + 1.0)*sin(Theta)*Pi[n]*zn/Rho;
+      vn3e1n[1] = cos(Phi)*Tau[n]*xxip/Rho;
+      vn3e1n[2] = -sin(Phi)*Pi[n]*xxip/Rho;
+      
+      // scattered field: BH p.94 (4.45)
+      std::complex<double> encap = std::pow(c_i, rn)*(2.0*rn + 1.0)/(rn*rn + rn);
+      for (int i = 0; i < 3; i++) {
+        Es[i] = Es[i] + encap*(c_i*an_[n]*vn3e1n[i] - bn_[n]*vm3o1n[i]);
+        Hs[i] = Hs[i] + encap*(c_i*bn_[n]*vn3o1n[i] + an_[n]*vm3e1n[i]);
+        //if (n<3) printf(" E[%d]=%g ", i,std::abs(Es[i]));
+        if (n<3) printf(" !!=%d=== %g ", i,std::abs(Es[i]));
+      }
+    }
+    
+    // incident E field: BH p.89 (4.21); cf. p.92 (4.37), p.93 (4.38)
+    // basis unit vectors = er, etheta, ephi
+    std::complex<double> eifac = std::exp(std::complex<double>(0.0, Rho*std::cos(Theta)));
+    {
+      using std::sin;
+      using std::cos;
+      Ei[0] = eifac*sin(Theta)*cos(Phi);
+      Ei[1] = eifac*cos(Theta)*cos(Phi);
+      Ei[2] = -eifac*sin(Phi);
+    }
+
+    // magnetic field
+    double hffact = 1.0/(cc_*mu_);
+    for (int i = 0; i < 3; i++) {
+      Hs[i] = hffact*Hs[i];
+    }
+    
+    // incident H field: BH p.26 (2.43), p.89 (4.21)
+    std::complex<double> hffacta = hffact;
+    std::complex<double> hifac = eifac*hffacta;
+    {
+      using std::sin;
+      using std::cos;
+      Hi[0] = hifac*sin(Theta)*sin(Phi);
+      Hi[1] = hifac*cos(Theta)*sin(Phi);
+      Hi[2] = hifac*cos(Phi);
+    }
+    
+    for (int i = 0; i < 3; i++) {
+      // electric field E [V m - 1] = EF*E0
+      E[i] = Ei[i] + Es[i];
+      H[i] = Hi[i] + Hs[i];
+      // printf("ext E[%d]=%g",i,std::abs(E[i]));
+    }
+   }  // end of void fieldExt(...)
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+  void MultiLayerMie::fieldInt(const double Rho, const double Phi, const double Theta, const  std::vector<double>& Pi, const std::vector<double>& Tau, std::vector<std::complex<double> >& E, std::vector<std::complex<double> >& H)  {
+    // printf("field int Qext = %g, Qsca = %g, Qabs = %g, Qbk = %g, \n",
+    //            GetQext(), GetQsca(), GetQabs(), GetQbk());
+    
+    std::complex<double> c_zero(0.0, 0.0), c_i(0.0, 1.0), c_one(1.0, 0.0);
+    std::vector<std::complex<double> > vm3o1n(3), vm3e1n(3), vn3o1n(3), vn3e1n(3);
+    std::vector<std::complex<double> > vm1o1n(3), vm1e1n(3), vn1o1n(3), vn1e1n(3);
+    std::vector<std::complex<double> > El(3,c_zero),Ei(3,c_zero), Hl(3,c_zero);
+    std::vector<std::complex<double> > bj(nmax_ + 1), by(nmax_ + 1), bd(nmax_ + 1);
+    int layer=0;  // layer number
+    std::complex<double> index_l;
+    for (int i = 0; i < size_parameter_.size() - 1; ++i) {
+      if (size_parameter_[i] < Rho && Rho <= size_parameter_[i + 1]) {
+        layer=i;
+      }
+    }
+    if (Rho > size_parameter_.back()) {
+      layer = size_parameter_.size();
+      index_l = c_one; 
+    } else {
+      index_l = index_[layer]; 
+    }
+   
+    std::complex<double> bessel_arg = Rho*index_l;
+    std::complex<double>& rh = bessel_arg;
+    std::complex<double> besselj_1 = std::sin(rh)/pow2(rh)-std::cos(rh)/rh;
+    printf("bessel arg = %g,%g   index=%g,%g   besselj[1]=%g,%g\n", bessel_arg.real(), bessel_arg.imag(), index_l.real(), index_l.imag(), besselj_1.real(), besselj_1.imag());
+    const int& l = layer;
+    printf("##########  layer %d ############\n",l);
+    // Calculate spherical Bessel and Hankel functions
+    sphericalBessel(bessel_arg,bj, by, bd);    
+    printf("besselj[1]=%g,%g\n", bj[1].real(), bj[1].imag());
+    printf("bessely[1]=%g,%g\n", by[1].real(), by[1].imag());
+    for (int n = 0; n < nmax_; n++) {
+      double rn = static_cast<double>(n + 1);
+      std::complex<double> znm1 = bj[n] + c_i*by[n];
+      std::complex<double> zn = bj[n + 1] + c_i*by[n + 1];
+      //if (n<3) printf("\nbesselh = %g,%g", zn.real(), zn.imag()); //!
+      // using BH 4.12 and 4.50
+      std::complex<double> xxip = Rho*(bj[n] + c_i*by[n]) - rn*zn;
+      //if (n<3) printf("\nxxip = %g,%g", xxip.real(), xxip.imag()); //!
+      
+      using std::sin;
+      using std::cos;
+      vm3o1n[0] = c_zero;
+      vm3o1n[1] = cos(Phi)*Pi[n]*zn;
+      vm3o1n[2] = -sin(Phi)*Tau[n]*zn;
+      // if (n<3)  printf("\nRE  vm3o1n[0]%g   vm3o1n[1]%g    vm3o1n[2]%g   \nIM vm3o1n[0]%g   vm3o1n[1]%g    vm3o1n[2]%g",
+      //              vm3o1n[0].real(), vm3o1n[1].real(), vm3o1n[2].real(),
+      //              vm3o1n[0].imag(), vm3o1n[1].imag(), vm3o1n[2].imag());
+      vm3e1n[0] = c_zero;
+      vm3e1n[1] = -sin(Phi)*Pi[n]*zn;
+      vm3e1n[2] = -cos(Phi)*Tau[n]*zn;
+      vn3o1n[0] = sin(Phi)*rn*(rn + 1.0)*sin(Theta)*Pi[n]*zn/Rho;
+      vn3o1n[1] = sin(Phi)*Tau[n]*xxip/Rho;
+      vn3o1n[2] = cos(Phi)*Pi[n]*xxip/Rho;
+      vn3e1n[0] = cos(Phi)*rn*(rn + 1.0)*sin(Theta)*Pi[n]*zn/Rho;
+      vn3e1n[1] = cos(Phi)*Tau[n]*xxip/Rho;
+      vn3e1n[2] = -sin(Phi)*Pi[n]*xxip/Rho;
+      // if (n<3)  printf("\nRE  vn3e1n[0]%g   vn3e1n[1]%g    vn3e1n[2]%g   \nIM vn3e1n[0]%g   vn3e1n[1]%g    vn3e1n[2]%g",
+      //              vn3e1n[0].real(), vn3e1n[1].real(), vn3e1n[2].real(),
+      //              vn3e1n[0].imag(), vn3e1n[1].imag(), vn3e1n[2].imag());
+      
+      znm1 = bj[n];
+      zn = bj[n + 1];
+      // znm1 = (bj[n] + c_i*by[n]).real();
+      // zn = (bj[n + 1] + c_i*by[n + 1]).real();
+      xxip = Rho*(bj[n]) - rn*zn;
+      if (n<3)printf("\nbesselj = %g,%g", zn.real(), zn.imag()); //!
+      vm1o1n[0] = c_zero;
+      vm1o1n[1] = cos(Phi)*Pi[n]*zn;
+      vm1o1n[2] = -sin(Phi)*Tau[n]*zn;
+      vm1e1n[0] = c_zero;
+      vm1e1n[1] = -sin(Phi)*Pi[n]*zn;
+      vm1e1n[2] = -cos(Phi)*Tau[n]*zn;
+      vn1o1n[0] = sin(Phi)*rn*(rn + 1.0)*sin(Theta)*Pi[n]*zn/Rho;
+      vn1o1n[1] = sin(Phi)*Tau[n]*xxip/Rho;
+      vn1o1n[2] = cos(Phi)*Pi[n]*xxip/Rho;
+      // if (n<3) printf("\nvn1o1n[2](%g) = cos(Phi)(%g)*Pi[n](%g)*xxip(%g)/Rho(%g)",
+      //                       std::abs(vn1o1n[2]), cos(Phi),Pi[n],std::abs(xxip),Rho);
+      vn1e1n[0] = cos(Phi)*rn*(rn + 1.0)*sin(Theta)*Pi[n]*zn/Rho;
+      vn1e1n[1] = cos(Phi)*Tau[n]*xxip/Rho;
+      vn1e1n[2] = -sin(Phi)*Pi[n]*xxip/Rho;
+      // if (n<3)  printf("\nRE  vm3o1n[0]%g   vm3o1n[1]%g    vm3o1n[2]%g   \nIM vm3o1n[0]%g   vm3o1n[1]%g    vm3o1n[2]%g",
+      //              vm3o1n[0].real(), vm3o1n[1].real(), vm3o1n[2].real(),
+      //              vm3o1n[0].imag(), vm3o1n[1].imag(), vm3o1n[2].imag());
+      
+      // scattered field: BH p.94 (4.45)
+      std::complex<double> encap = std::pow(c_i, rn)*(2.0*rn + 1.0)/(rn*rn + rn);
+      // if (n<3) printf("\n===== n=%d ======\n",n);
+      for (int i = 0; i < 3; i++) {
+        // if (n<3 && i==0) printf("\nn=%d",n);
+        // if (n<3) printf("\nbefore !El[%d]=%g,%g! ", i, El[i].real(), El[i].imag());
+        Ei[i] = encap*(cl_n_[l][n]*vm1o1n[i] - c_i*dl_n_[l][n]*vn1e1n[i]
+                       + c_i*al_n_[l][n]*vn3e1n[i] - bl_n_[l][n]*vm3o1n[i]);
+        El[i] = El[i] + encap*(cl_n_[l][n]*vm1o1n[i] - c_i*dl_n_[l][n]*vn1e1n[i]
+                               + c_i*al_n_[l][n]*vn3e1n[i] - bl_n_[l][n]*vm3o1n[i]);
+        Hl[i] = Hl[i] + encap*(-dl_n_[l][n]*vm1e1n[i] - c_i*cl_n_[l][n]*vn1o1n[i]
+                               + c_i*bl_n_[l][n]*vn3o1n[i] + al_n_[l][n]*vm3e1n[i]);
+        // printf("\n !Ei[%d]=%g,%g! ", i, Ei[i].real(), Ei[i].imag());
+        // if (n<3) printf("\n !El[%d]=%g,%g! ", i, El[i].real(), El[i].imag());
+        // //printf(" ===%d=== %g ", i,std::abs(cl_n_[l][n]*vm1o1n[i] - c_i*dl_n_[l][n]*vn1e1n[i]));
+        // if (n<3) printf(" ===%d=== %g ", i,std::abs(//-dl_n_[l][n]*vm1e1n[i] 
+        //                                             //- c_i*cl_n_[l][n]*
+        //                                             vn1o1n[i]
+        //                                             // + c_i*bl_n_[l][n]*vn3o1n[i]
+        //                                             // + al_n_[l][n]*vm3e1n[i]
+        //                      ));
+        // if (n<3) printf(" --- Ei[%d]=%g! ", i,std::abs(encap*(vm1o1n[i] - c_i*vn1e1n[i])));
+
+      }
+      //if (n<3) printf(" bj=%g \n", std::abs(bj[n]));
+    }  // end of for all n
+    
+    // magnetic field
+    double hffact = 1.0/(cc_*mu_);
+    for (int i = 0; i < 3; i++) {
+      Hl[i] = hffact*Hl[i];
+    }
+    
+    for (int i = 0; i < 3; i++) {
+      // electric field E [V m - 1] = EF*E0
+      E[i] = El[i];
+      H[i] = Hl[i];
+      printf("\n !El[%d]=%g,%g! ", i, El[i].real(), El[i].imag());
+      //printf(" E[%d]=%g",i,std::abs(El[i]));
+    }
+   }  // end of void fieldExt(...)
+  // ********************************************************************** //
+  // ********************************************************************** //
+  // ********************************************************************** //
+
+  //**********************************************************************************//
+  // This function calculates complex electric and magnetic field in the surroundings //
+  // and inside (TODO) the particle.                                                  //
+  //                                                                                  //
+  // Input parameters:                                                                //
+  //   L: Number of layers                                                            //
+  //   pl: Index of PEC layer. If there is none just send 0 (zero)                    //
+  //   x: Array containing the size parameters of the layers [0..L - 1]                 //
+  //   m: Array containing the relative refractive indexes of the layers [0..L - 1]     //
+  //   nmax: Maximum number of multipolar expansion terms to be used for the          //
+  //         calculations. Only use it if you know what you are doing, otherwise      //
+  //         set this parameter to 0 (zero) and the function will calculate it.       //
+  //   ncoord: Number of coordinate points                                            //
+  //   Coords: Array containing all coordinates where the complex electric and        //
+  //           magnetic fields will be calculated                                     //
+  //                                                                                  //
+  // Output parameters:                                                               //
+  //   E, H: Complex electric and magnetic field at the provided coordinates          //
+  //                                                                                  //
+  // Return value:                                                                    //
+  //   Number of multipolar expansion terms used for the calculations                 //
+  //**********************************************************************************//
+  void MultiLayerMie::RunFieldCalculations() {
+    // Calculate scattering coefficients an_ and bn_
+    RunMieCalculations();
+    //nmax_=10;
+    IntScattCoeffs();
+
+    std::vector<double> Pi(nmax_), Tau(nmax_);
+    long total_points = coords_sp_[0].size();
+    E_field_.resize(total_points);
+    H_field_.resize(total_points);
+    for (auto& f:E_field_) f.resize(3);
+    for (auto& f:H_field_) f.resize(3);
+
+    for (int point = 0; point < total_points; ++point) {
+      const double& Xp = coords_sp_[0][point];
+      const double& Yp = coords_sp_[1][point];
+      const double& Zp = coords_sp_[2][point];
+      printf("X=%g, Y=%g, Z=%g\n", Xp, Yp, Zp);
+      // Convert to spherical coordinates
+      double Rho, Phi, Theta;
+      Rho = std::sqrt(pow2(Xp) + pow2(Yp) + pow2(Zp));
+      // printf("Rho=%g\n", Rho);
+      // Avoid convergence problems due to Rho too small
+      if (Rho < 1e-10) Rho = 1e-10;
+      // If Rho=0 then Theta is undefined. Just set it to zero to avoid problems
+      if (Rho == 0.0) Theta = 0.0;
+      else Theta = std::acos(Zp/Rho);
+      // printf("Theta=%g\n", Theta);
+      // If Xp=Yp=0 then Phi is undefined. Just set it to zero to zero to avoid problems
+      if (Xp == 0.0 && Yp == 0.0) Phi = 0.0;
+      else Phi = std::acos(Xp/std::sqrt(pow2(Xp) + pow2(Yp)));
+      // printf("Phi=%g\n", Phi);
+
+      calcSinglePiTau(std::cos(Theta), Pi, Tau);     
+      //*******************************************************//
+      // external scattering field = incident + scattered      //
+      // BH p.92 (4.37), 94 (4.45), 95 (4.50)                  //
+      // assume: medium is non-absorbing; refim = 0; Uabs = 0  //
+      //*******************************************************//
+      // This array contains the fields in spherical coordinates
+      std::vector<std::complex<double> > Es(3), Hs(3);
+      const double outer_size = size_parameter_.back();
+      // Firstly the easiest case: the field outside the particle
+      printf("rho=%g, outer=%g  ", Rho, outer_size);
+      if (Rho >= outer_size) {
+        fieldExt(Rho, Phi, Theta, Pi, Tau, Es, Hs);
+        printf("\nFin E ext: %g,%g,%g   Rho=%g\n", std::abs(Es[0]), std::abs(Es[1]),std::abs(Es[2]), Rho);
+      } else {
+        fieldInt(Rho, Phi, Theta, Pi, Tau, Es, Hs);      
+        printf("\nFin E int: %g,%g,%g   Rho=%g\n", std::abs(Es[0]), std::abs(Es[1]),std::abs(Es[2]), Rho);
+      }
+      std::complex<double>& Ex = E_field_[point][0];
+      std::complex<double>& Ey = E_field_[point][1];
+      std::complex<double>& Ez = E_field_[point][2];
+      std::complex<double>& Hx = H_field_[point][0];
+      std::complex<double>& Hy = H_field_[point][1];
+      std::complex<double>& Hz = H_field_[point][2];
+      //Now, convert the fields back to cartesian coordinates
+      {
+        using std::sin;
+        using std::cos;
+        Ex = sin(Theta)*cos(Phi)*Es[0] + cos(Theta)*cos(Phi)*Es[1] - sin(Phi)*Es[2];
+        Ey = sin(Theta)*sin(Phi)*Es[0] + cos(Theta)*sin(Phi)*Es[1] + cos(Phi)*Es[2];
+        Ez = cos(Theta)*Es[0] - sin(Theta)*Es[1];
+      
+        Hx = sin(Theta)*cos(Phi)*Hs[0] + cos(Theta)*cos(Phi)*Hs[1] - sin(Phi)*Hs[2];
+        Hy = sin(Theta)*sin(Phi)*Hs[0] + cos(Theta)*sin(Phi)*Hs[1] + cos(Phi)*Hs[2];
+        Hz = cos(Theta)*Hs[0] - sin(Theta)*Hs[1];
+      }
+      printf("Cart E: %g,%g,%g   Rho=%g\n", std::abs(Ex), std::abs(Ey),std::abs(Ez),
+             Rho);
+    }  // end of for all field coordinates
+    
+  }  //  end of   void MultiLayerMie::RunFieldCalculations()
+
+}  // end of namespace nmie

+ 178 - 0
nmie-core.h

@@ -0,0 +1,178 @@
+//**********************************************************************************//
+//    Copyright (C) 2009-2015  Ovidio Pena <ovidio@bytesfall.com>                   //
+//                                                                                  //
+//    This file is part of scattnlay                                                //
+//                                                                                  //
+//    This program is free software: you can redistribute it and/or modify          //
+//    it under the terms of the GNU General Public License as published by          //
+//    the Free Software Foundation, either version 3 of the License, or             //
+//    (at your option) any later version.                                           //
+//                                                                                  //
+//    This program is distributed in the hope that it will be useful,               //
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                 //
+//    GNU General Public License for more details.                                  //
+//                                                                                  //
+//    The only additional remark is that we expect that all publications            //
+//    describing work using this software, or all commercial products               //
+//    using it, cite the following reference:                                       //
+//    [1] O. Pena and U. Pal, "Scattering of electromagnetic radiation by           //
+//        a multilayered sphere," Computer Physics Communications,                  //
+//        vol. 180, Nov. 2009, pp. 2348-2354.                                       //
+//                                                                                  //
+//    You should have received a copy of the GNU General Public License             //
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.         //
+//**********************************************************************************//
+
+#define VERSION "0.3.1"
+#include <array>
+#include <complex>
+#include <cstdlib>
+#include <iostream>
+#include <vector>
+
+namespace nmie {
+
+  int nMie_wrapper(int L, std::vector<double>& x, std::vector<std::complex<double> >& m, int nTheta, std::vector<double>& Theta, double *Qext, double *Qsca, double *Qabs, double *Qbk, double *Qpr, double *g, double *Albedo, std::vector<std::complex<double> >& S1, std::vector<std::complex<double> >& S2);
+  int nField(const int L, const int pl, const std::vector<double>& x, const std::vector<std::complex<double> >& m, const int nmax, const int ncoord, const std::vector<double>& Xp, const std::vector<double>& Yp, const std::vector<double>& Zp, std::vector<std::vector<std::complex<double> > >& E, std::vector<std::vector<std::complex<double> > >& H);
+
+  class MultiLayerMie {
+   public:
+    // Run calculation
+    void RunMieCalculations();
+    void RunFieldCalculations();
+
+    // Return calculation results
+    double GetQext();
+    double GetQsca();
+    double GetQabs();
+    double GetQbk();
+    double GetQpr();
+    double GetAsymmetryFactor();
+    double GetAlbedo();
+    std::vector<std::complex<double> > GetS1();
+    std::vector<std::complex<double> > GetS2();
+
+    std::vector<std::complex<double> > GetAn(){return an_;};
+    std::vector<std::complex<double> > GetBn(){return bn_;}; 
+
+    // Problem definition
+    // Add new layer
+    void AddNewLayer(double layer_width, std::complex<double> layer_index);
+    // Modify width of the layer
+    void SetLayerWidth(std::vector<double> layer_width, int layer_position = 0);
+    // Modify refractive index of the layer
+    void SetLayerIndex(std::vector< std::complex<double> > layer_index, int layer_position = 0);
+    // Modify width of all layers
+    void SetLayersWidth(std::vector<double> layer_width);
+    // Modify refractive index of all layers
+    void SetLayerIndex(std::vector< std::complex<double> > layer_index);
+    // Set PEC layer
+    void SetPECLayer(int layer_position = 0);
+
+    // Set maximun number of terms to be used
+    void SetMaxTerms(int nmax);
+    // Get maximun number of terms
+    int GetMaxTermsUsed() {return nmax_used_;};
+
+    // Clear layer information
+    void ClearLayers();
+
+    // Applied units requests
+    double GetTotalRadius();
+    double GetCoreRadius();
+    double GetLayerWidth(int layer_position = 0);
+    std::vector<double> GetLayersWidth();
+    std::vector<std::complex<double> > GetLayersIndex();  
+    std::vector<std::array<double, 3> > GetFieldCoords();
+
+    std::vector<std::vector< std::complex<double> > > GetFieldE(){return E_field_;};   // {X[], Y[], Z[]}
+    std::vector<std::vector< std::complex<double> > > GetFieldH(){return H_field_;};
+  private:
+    void Nstop();
+    void Nmax(int first_layer);
+    void sbesjh(std::complex<double> z, std::vector<std::complex<double> >& jn,
+	            std::vector<std::complex<double> >& jnp, std::vector<std::complex<double> >& h1n,
+	            std::vector<std::complex<double> >& h1np);
+    void sphericalBessel(std::complex<double> z, std::vector<std::complex<double> >& bj,
+			             std::vector<std::complex<double> >& by, std::vector<std::complex<double> >& bd);
+    std::complex<double> calc_an(int n, double XL, std::complex<double> Ha, std::complex<double> mL,
+	                             std::complex<double> PsiXL, std::complex<double> ZetaXL,
+				                 std::complex<double> PsiXLM1, std::complex<double> ZetaXLM1);
+    std::complex<double> calc_bn(int n, double XL, std::complex<double> Hb, std::complex<double> mL,
+	                             std::complex<double> PsiXL, std::complex<double> ZetaXL,
+				                 std::complex<double> PsiXLM1, std::complex<double> ZetaXLM1);
+    std::complex<double> calc_S1(int n, std::complex<double> an, std::complex<double> bn,
+				                 double Pi, double Tau);
+    std::complex<double> calc_S2(int n, std::complex<double> an, std::complex<double> bn,
+				                 double Pi, double Tau);
+    void calcPsiZeta(std::complex<double> x, 
+		             std::vector<std::complex<double> > D1,
+		             std::vector<std::complex<double> > D3,
+		             std::vector<std::complex<double> >& Psi,
+		             std::vector<std::complex<double> >& Zeta);
+    std::complex<double> calcD1confra(int N, const std::complex<double> z);
+    void calcD1D3(std::complex<double> z,
+		          std::vector<std::complex<double> >& D1,
+		          std::vector<std::complex<double> >& D3);
+    void calcSinglePiTau(const double& costheta, std::vector<double>& Pi,
+			             std::vector<double>& Tau);
+    void calcAllPiTau(std::vector< std::vector<double> >& Pi,
+		              std::vector< std::vector<double> >& Tau);
+    void ExtScattCoeffs(std::vector<std::complex<double> >& an, std::vector<std::complex<double> >& bn); 
+    void IntScattCoeffs();
+    void IntScattCoeffsInit();
+
+    void fieldExt(const double Rho, const double Phi, const double Theta, const  std::vector<double>& Pi, const std::vector<double>& Tau, std::vector<std::complex<double> >& E, std::vector<std::complex<double> >& H);
+
+    void fieldInt(const double Rho, const double Phi, const double Theta, const  std::vector<double>& Pi, const std::vector<double>& Tau, std::vector<std::complex<double> >& E, std::vector<std::complex<double> >& H);
+    
+    bool areIntCoeffsCalc_ = false;
+    bool areExtCoeffsCalc_ = false;
+    bool isMieCalculated_ = false;
+    double wavelength_ = 1.0;
+    double total_radius_ = 0.0;
+
+    // Size parameter for all layers
+    std::vector<double> width_;
+    // Refractive index for all layers
+    std::vector< std::complex<double> > index_;
+    // Scattering angles for scattering pattern in radians
+    std::vector<double> theta_;
+    // Should be -1 if there is no PEC.
+    int PEC_layer_position_ = -1;
+
+    // with Nmax(int first_layer);
+    int nmax_ = -1;
+    int nmax_used_ = -1;
+    int nmax_preset_ = -1;
+    // Scattering coefficients
+    std::vector<std::complex<double> > an_, bn_;
+    std::vector< std::vector<double> > coords_sp_;
+    // TODO: check if l index is reversed will lead to performance
+    // boost, if $a^(L+1)_n$ stored in al_n_[n][0], $a^(L)_n$ in
+    // al_n_[n][1] and so on...
+    // at the moment order is forward!
+    std::vector< std::vector<std::complex<double> > > al_n_, bl_n_, cl_n_, dl_n_;
+    /// Store result
+    double Qsca_ = 0.0, Qext_ = 0.0, Qabs_ = 0.0, Qbk_ = 0.0, Qpr_ = 0.0, asymmetry_factor_ = 0.0, albedo_ = 0.0;
+    std::vector<std::vector< std::complex<double> > > E_field_, H_field_;  // {X[], Y[], Z[]}
+    // Mie efficinecy from each multipole channel.
+    std::vector<double> Qsca_ch_, Qext_ch_, Qabs_ch_, Qbk_ch_, Qpr_ch_;
+    std::vector<double> Qsca_ch_norm_, Qext_ch_norm_, Qabs_ch_norm_, Qbk_ch_norm_, Qpr_ch_norm_;
+    std::vector<std::complex<double> > S1_, S2_;
+
+    //Used constants
+    const double PI_=3.14159265358979323846;  
+    // light speed [m s-1]
+    double const cc_ = 2.99792458e8;
+    // assume non-magnetic (MU=MU0=const) [N A-2]
+    double const mu_ = 4.0*PI_*1.0e-7;
+
+    //Temporary variables
+    std::vector<std::complex<double> > PsiZeta_;
+
+
+  };  // end of class MultiLayerMie
+
+}  // end of namespace nmie

+ 54 - 57
nmie-wrapper.cc

@@ -505,6 +505,7 @@ namespace nmie {
     }
     nmax_ += 15;  // Final nmax_ value
   }
+
   //**********************************************************************************//
   // This function calculates the spherical Bessel (jn) and Hankel (h1n) functions    //
   // and their derivatives for a given complex value z. See pag. 87 B&H.              //
@@ -796,7 +797,7 @@ c    MM + 1  and - 1, alternately
     MM = - 1; 
     KK = 2*N +3; //debug 3
 // c                                 ** Eq. R25b, k=2
-    CAK    = static_cast<std::complex<double> >(MM*KK) * ZINV; //debug -3 ZINV
+    CAK    = static_cast<std::complex<double> >(MM*KK)*ZINV; //debug -3 ZINV
     CDENOM = CAK;
     CNUMER = CDENOM + one/CONFRA; //-3zinv+z
     KOUNT  = 1;
@@ -807,15 +808,15 @@ c    MM + 1  and - 1, alternately
         throw std::invalid_argument("ConFra--Iteration failed to converge!\n");
       }
       MM *= - 1;      KK += 2;  //debug  mm=1 kk=5
-      CAK = static_cast<std::complex<double> >(MM*KK) * ZINV; //    ** Eq. R25b //debug 5zinv
+      CAK = static_cast<std::complex<double> >(MM*KK)*ZINV; //    ** Eq. R25b //debug 5zinv
      //  //c ** Eq. R32    Ill-conditioned case -- stride two terms instead of one
      //  if (std::abs(CNUMER/CAK) >= EPS1 ||  std::abs(CDENOM/CAK) >= EPS1) {
      //         //c                       ** Eq. R34
-     //         CNTN   = CAK * CNUMER + 1.0;
-     //         CDTD   = CAK * CDENOM + 1.0;
-     //         CONFRA = (CNTN/CDTD) * CONFRA; // ** Eq. R33
+     //         CNTN   = CAK*CNUMER + 1.0;
+     //         CDTD   = CAK*CDENOM + 1.0;
+     //         CONFRA = (CNTN/CDTD)*CONFRA; // ** Eq. R33
      //         MM  *= - 1;        KK  += 2;
-     //         CAK = static_cast<std::complex<double> >(MM*KK) * ZINV; // ** Eq. R25b
+     //         CAK = static_cast<std::complex<double> >(MM*KK)*ZINV; // ** Eq. R25b
      //         //c                        ** Eq. R35
      //         CNUMER = CAK + CNUMER/CNTN;
      //         CDENOM = CAK + CDENOM/CDTD;
@@ -826,7 +827,7 @@ c    MM + 1  and - 1, alternately
       {
         CAPT   = CNUMER/CDENOM; // ** Eq. R27 //debug (-3zinv + z)/(-3zinv)
         // printf("re(%g):im(%g)**\t", CAPT.real(), CAPT.imag());
-       CONFRA = CAPT * CONFRA; // ** Eq. R26
+       CONFRA = CAPT*CONFRA; // ** Eq. R26
        //if (N == 0) {output=true;printf(" re:");prn(CONFRA.real());printf(" im:"); prn(CONFRA.imag());output=false;};
        //c                                  ** Check for convergence; Eq. R31
        if (std::abs(CAPT.real() - 1.0) >= EPS2 ||  std::abs(CAPT.imag()) >= EPS2) {
@@ -931,6 +932,7 @@ c    MM + 1  and - 1, alternately
       //calcSinglePiTau(std::cos(theta_[t]), Pi[t], Tau[t]); // It is slow!!
     }
   }  // end of void MultiLayerMie::calcAllPiTau(...)
+
   //**********************************************************************************//
   // This function calculates the scattering coefficients required to calculate       //
   // both the near- and far-field parameters.                                         //
@@ -950,7 +952,7 @@ c    MM + 1  and - 1, alternately
   // Return value:                                                                    //
   //   Number of multipolar expansion terms used for the calculations                 //
   //**********************************************************************************//
-  void MultiLayerMie::ScattCoeffs(std::vector<std::complex<double> >& an,
+  void MultiLayerMie::ExtScattCoeffs(std::vector<std::complex<double> >& an,
                                   std::vector<std::complex<double> >& bn) {
     const std::vector<double>& x = size_parameter_;
     const std::vector<std::complex<double> >& m = index_;
@@ -966,6 +968,8 @@ c    MM + 1  and - 1, alternately
     // int fl = (pl > - 1) ? pl : 0;
     // This will give the same result, however, it corresponds the
     // logic - if there is PEC, than first layer is PEC.
+    // Well, I followed the logic: First layer is always zero unless it has 
+    // an upper PEC layer.
     int fl = (pl > 0) ? pl : 0;
     if (nmax_ <= 0) Nmax(fl);
 
@@ -979,22 +983,23 @@ c    MM + 1  and - 1, alternately
     //**************************************************************************//
     // Allocate memory to the arrays
     std::vector<std::complex<double> > D1_mlxl(nmax_ + 1), D1_mlxlM1(nmax_ + 1),
-      D3_mlxl(nmax_ + 1), D3_mlxlM1(nmax_ + 1);
+                                       D3_mlxl(nmax_ + 1), D3_mlxlM1(nmax_ + 1);
+
     std::vector<std::vector<std::complex<double> > > Q(L), Ha(L), Hb(L);
+
     for (int l = 0; l < L; l++) {
-      // D1_mlxl[l].resize(nmax_ + 1);
-      // D1_mlxlM1[l].resize(nmax_ + 1);
-      // D3_mlxl[l].resize(nmax_ + 1);
-      // D3_mlxlM1[l].resize(nmax_ + 1);
       Q[l].resize(nmax_ + 1);
       Ha[l].resize(nmax_);
       Hb[l].resize(nmax_);
     }
+
     an.resize(nmax_);
     bn.resize(nmax_);
     PsiZeta_.resize(nmax_ + 1);
+
     std::vector<std::complex<double> > D1XL(nmax_ + 1), D3XL(nmax_ + 1), 
-      PsiXL(nmax_ + 1), ZetaXL(nmax_ + 1);
+                                       PsiXL(nmax_ + 1), ZetaXL(nmax_ + 1);
+
     //*************************************************//
     // Calculate D1 and D3 for z1 in the first layer   //
     //*************************************************//
@@ -1044,7 +1049,7 @@ c    MM + 1  and - 1, alternately
       //*********************************************//
       // Upward recurrence for Q - equations (19a) and (19b)
       Num = std::exp(-2.0*(z1.imag() - z2.imag()))
-        * std::complex<double>(std::cos(-2.0*z2.real()) - std::exp(-2.0*z2.imag()), std::sin(-2.0*z2.real()));
+       *std::complex<double>(std::cos(-2.0*z2.real()) - std::exp(-2.0*z2.imag()), std::sin(-2.0*z2.real()));
       Denom = std::complex<double>(std::cos(-2.0*z1.real()) - std::exp(-2.0*z1.imag()), std::sin(-2.0*z1.real()));
       Q[l][0] = Num/Denom;
       for (int n = 1; n <= nmax_; n++) {
@@ -1108,7 +1113,7 @@ c    MM + 1  and - 1, alternately
         bn[n] = PsiXL[n + 1]/ZetaXL[n + 1];
       }
     }  // end of for an and bn terms
-  }  // end of void MultiLayerMie::ScattCoeffs(...)
+  }  // end of void MultiLayerMie::ExtScattCoeffs(...)
   // ********************************************************************** //
   // ********************************************************************** //
   // ********************************************************************** //
@@ -1138,7 +1143,7 @@ c    MM + 1  and - 1, alternately
     Qbk_ch_norm_.resize(nmax_ - 1);
     Qpr_ch_norm_.resize(nmax_ - 1);
     // Initialize the scattering amplitudes
-    std::vector<std::complex<double> >        tmp1(theta_.size(),std::complex<double>(0.0, 0.0));
+    std::vector<std::complex<double> > tmp1(theta_.size(),std::complex<double>(0.0, 0.0));
     S1_.swap(tmp1);
     S2_ = S1_;
   }
@@ -1162,15 +1167,15 @@ c    MM + 1  and - 1, alternately
   //                                                                                  //
   // Input parameters:                                                                //
   //   L: Number of layers                                                            //
-  //   pl: Index of PEC layer. If there is none just send - 1                          //
-  //   x: Array containing the size parameters of the layers [0..L - 1]                 //
-  //   m: Array containing the relative refractive indexes of the layers [0..L - 1]     //
+  //   pl: Index of PEC layer. If there is none just send -1                          //
+  //   x: Array containing the size parameters of the layers [0..L-1]                 //
+  //   m: Array containing the relative refractive indexes of the layers [0..L-1]     //
   //   nTheta: Number of scattering angles                                            //
   //   Theta: Array containing all the scattering angles where the scattering         //
   //          amplitudes will be calculated                                           //
-  //   nmax_: Maximum number of multipolar expansion terms to be used for the          //
+  //   nmax_: Maximum number of multipolar expansion terms to be used for the         //
   //         calculations. Only use it if you know what you are doing, otherwise      //
-  //         set this parameter to - 1 and the function will calculate it              //
+  //         set this parameter to -1 and the function will calculate it              //
   //                                                                                  //
   // Output parameters:                                                               //
   //   Qext: Efficiency factor for extinction                                         //
@@ -1195,7 +1200,7 @@ c    MM + 1  and - 1, alternately
       throw std::invalid_argument("Initialize model first!");
     const std::vector<double>& x = size_parameter_;
     // Calculate scattering coefficients
-    ScattCoeffs(an_, bn_);
+    ExtScattCoeffs(an_, bn_);
 
     // std::vector< std::vector<double> > Pi(nmax_), Tau(nmax_);
     std::vector< std::vector<double> > Pi, Tau;
@@ -1276,7 +1281,7 @@ c    MM + 1  and - 1, alternately
   // ********************************************************************** //
   // ********************************************************************** //
   // ********************************************************************** //
-  void MultiLayerMie::ScattCoeffsLayerdInit() {
+  void MultiLayerMie::IntScattCoeffsInit() {
     const int L = index_.size();
     // we need to fill
     // std::vector< std::vector<std::complex<double> > > al_n_, bl_n_, cl_n_, dl_n_;
@@ -1300,25 +1305,25 @@ c    MM + 1  and - 1, alternately
       bl_n_[L][i] = bn_[i];
       cl_n_[L][i] = c_one;
       dl_n_[L][i] = c_one;
-      if (i<3) printf(" (%g) ", std::abs(an_[i]));
+      if (i < 3) printf(" (%g) ", std::abs(an_[i]));
     }
 
   }
   // ********************************************************************** //
   // ********************************************************************** //
   // ********************************************************************** //
-  void MultiLayerMie::ScattCoeffsLayerd() {
+  void MultiLayerMie::IntScattCoeffs() {
     if (!isMieCalculated_)
-      throw std::invalid_argument("(ScattCoeffsLayerd) You should run calculations first!");
-    ScattCoeffsLayerdInit();
+      throw std::invalid_argument("(IntScattCoeffs) You should run calculations first!");
+    IntScattCoeffsInit();
     const int L = index_.size();
     std::vector<std::complex<double> > z(L), z1(L);
     for (int i = 0; i < L - 1; ++i) {
       z[i]  =size_parameter_[i]*index_[i];
       z1[i]=size_parameter_[i]*index_[i + 1];
     }
-    z[L - 1]  =size_parameter_[L - 1]*index_[L - 1];
-    z1[L - 1]  =size_parameter_[L - 1];
+    z[L - 1] = size_parameter_[L - 1]*index_[L - 1];
+    z1[L - 1] = size_parameter_[L - 1];
     std::vector< std::vector<std::complex<double> > > D1z(L), D1z1(L), D3z(L), D3z1(L);
     std::vector< std::vector<std::complex<double> > > Psiz(L), Psiz1(L), Zetaz(L), Zetaz1(L);
     for (int l = 0; l < L; ++l) {
@@ -1345,37 +1350,31 @@ c    MM + 1  and - 1, alternately
     for (int l = L - 1; l >= 0; --l) {
       for (int n = 0; n < nmax_; ++n) {
         // al_n
-        auto denom = m1[l]*Zetaz[l][n + 1] * (D1z[l][n + 1] - D3z[l][n + 1]);
-        al_n_[l][n] = D1z[l][n + 1]* m1[l]
-          *(al_n_[l + 1][n]*Zetaz1[l][n + 1] - dl_n_[l + 1][n]*Psiz1[l][n + 1])
-          - m[l]*(-D1z1[l][n + 1]*dl_n_[l + 1][n]*Psiz1[l][n + 1]
-                  +D3z1[l][n + 1]*al_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        auto denom = m1[l]*Zetaz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        al_n_[l][n] = D1z[l][n + 1]*m1[l]*(al_n_[l + 1][n]*Zetaz1[l][n + 1] - dl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m[l]*(-D1z1[l][n + 1]*dl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*al_n_[l + 1][n]*Zetaz1[l][n + 1]);
         al_n_[l][n] /= denom;
-        // if (n<2) printf("denom[%d][%d]:%g \n", l, n,
-        //                   std::abs(Psiz[l][n + 1]));
+
         // dl_n
-        denom = m1[l]*Psiz[l][n + 1] * (D1z[l][n + 1] - D3z[l][n + 1]);
-        dl_n_[l][n] = D3z[l][n + 1]*m1[l]
-          *(al_n_[l + 1][n]*Zetaz1[l][n + 1] - dl_n_[l + 1][n]*Psiz1[l][n + 1])
-          - m[l]*(-D1z1[l][n + 1]*dl_n_[l + 1][n]*Psiz1[l][n + 1]
-                  +D3z1[l][n + 1]*al_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        denom = m1[l]*Psiz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        dl_n_[l][n] = D3z[l][n + 1]*m1[l]*(al_n_[l + 1][n]*Zetaz1[l][n + 1] - dl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m[l]*(-D1z1[l][n + 1]*dl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*al_n_[l + 1][n]*Zetaz1[l][n + 1]);
         dl_n_[l][n] /= denom;
+
         // bl_n
-        denom = m1[l]*Zetaz[l][n + 1] * (D1z[l][n + 1] - D3z[l][n + 1]);
-        bl_n_[l][n] = D1z[l][n + 1]* m[l]
-          *(bl_n_[l + 1][n]*Zetaz1[l][n + 1] - cl_n_[l + 1][n]*Psiz1[l][n + 1])
-          - m1[l]*(-D1z1[l][n + 1]*cl_n_[l + 1][n]*Psiz1[l][n + 1]
-                  +D3z1[l][n + 1]*bl_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        denom = m1[l]*Zetaz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        bl_n_[l][n] = D1z[l][n + 1]*m[l]*(bl_n_[l + 1][n]*Zetaz1[l][n + 1] - cl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m1[l]*(-D1z1[l][n + 1]*cl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*bl_n_[l + 1][n]*Zetaz1[l][n + 1]);
         bl_n_[l][n] /= denom;
+
         // cl_n
-        denom = m1[l]*Psiz[l][n + 1] * (D1z[l][n + 1] - D3z[l][n + 1]);
-        cl_n_[l][n] = D3z[l][n + 1]*m[l]
-          *(bl_n_[l + 1][n]*Zetaz1[l][n + 1] - cl_n_[l + 1][n]*Psiz1[l][n + 1])
-          - m1[l]*(-D1z1[l][n + 1]*cl_n_[l + 1][n]*Psiz1[l][n + 1]
-                  +D3z1[l][n + 1]*bl_n_[l + 1][n]*Zetaz1[l][n + 1]);
+        denom = m1[l]*Psiz[l][n + 1]*(D1z[l][n + 1] - D3z[l][n + 1]);
+        cl_n_[l][n] = D3z[l][n + 1]*m[l]*(bl_n_[l + 1][n]*Zetaz1[l][n + 1] - cl_n_[l + 1][n]*Psiz1[l][n + 1])
+                      - m1[l]*(-D1z1[l][n + 1]*cl_n_[l + 1][n]*Psiz1[l][n + 1] + D3z1[l][n + 1]*bl_n_[l + 1][n]*Zetaz1[l][n + 1]);
         cl_n_[l][n] /= denom;   
       }  // end of all n
     }  // end of for all l
+
     // Check the result and change  an__0 and bn__0 for exact zero
     for (int n = 0; n < nmax_; ++n) {
       if (std::abs(al_n_[0][n]) < 1e-10) al_n_[0][n] = 0.0;
@@ -1597,10 +1596,8 @@ c    MM + 1  and - 1, alternately
       for (int i = 0; i < 3; i++) {
         // if (n<3 && i==0) printf("\nn=%d",n);
         // if (n<3) printf("\nbefore !El[%d]=%g,%g! ", i, El[i].real(), El[i].imag());
-        Ei[i] = encap*(
-                       cl_n_[l][n]*vm1o1n[i] - c_i*dl_n_[l][n]*vn1e1n[i]
-          + c_i*al_n_[l][n]*vn3e1n[i] - bl_n_[l][n]*vm3o1n[i]
-);
+        Ei[i] = encap*(cl_n_[l][n]*vm1o1n[i] - c_i*dl_n_[l][n]*vn1e1n[i]
+                       + c_i*al_n_[l][n]*vn3e1n[i] - bl_n_[l][n]*vm3o1n[i]);
         El[i] = El[i] + encap*(cl_n_[l][n]*vm1o1n[i] - c_i*dl_n_[l][n]*vn1e1n[i]
                                + c_i*al_n_[l][n]*vn3e1n[i] - bl_n_[l][n]*vm3o1n[i]);
         Hl[i] = Hl[i] + encap*(-dl_n_[l][n]*vm1e1n[i] - c_i*cl_n_[l][n]*vn1o1n[i]
@@ -1664,7 +1661,7 @@ c    MM + 1  and - 1, alternately
     // Calculate scattering coefficients an_ and bn_
     RunMieCalculations();
     //nmax_=10;
-    ScattCoeffsLayerd();
+    IntScattCoeffs();
 
     std::vector<double> Pi(nmax_), Tau(nmax_);
     long total_points = coords_sp_[0].size();

+ 11 - 13
nmie-wrapper.h

@@ -120,8 +120,7 @@ namespace nmie {
       GetFieldE(){return E_field_;};   // {X[], Y[], Z[]}
     std::vector<std::vector< std::complex<double> > >
       GetFieldH(){return H_field_;};
-    std::vector< std::vector<double> >   GetSpectra(double from_WL, double to_WL,
-                                                   int samples);  // ext, sca, abs, bk
+    std::vector< std::vector<double> > GetSpectra(double from_WL, double to_WL, int samples);  // ext, sca, abs, bk
     double GetRCSext();
     double GetRCSsca();
     double GetRCSabs();
@@ -129,19 +128,16 @@ namespace nmie {
     std::vector<double> GetPatternEk();
     std::vector<double> GetPatternHk();
     std::vector<double> GetPatternUnpolarized();
-    
-
 
     // Size parameter units
-    std::vector<double>                  GetLayerWidthSP();
+    std::vector<double> GetLayerWidthSP();
     // Same as to get target and coating index
-    std::vector< std::complex<double> >  GetLayerIndex();  
-    std::vector< std::array<double,3> >   GetFieldPointsSP();
+    std::vector< std::complex<double> > GetLayerIndex();  
+    std::vector< std::array<double,3> > GetFieldPointsSP();
     // Do we need normalize field to size parameter?
     /* std::vector<std::vector<std::complex<double> > >  GetFieldESP(); */
     /* std::vector<std::vector<std::complex<double> > >  GetFieldHSP(); */
-    std::vector< std::array<double,5> >   GetSpectraSP(double from_SP, double to_SP,
-						       int samples);  // WL,ext, sca, abs, bk
+    std::vector< std::array<double,5> > GetSpectraSP(double from_SP, double to_SP, int samples);  // WL,ext, sca, abs, bk
     double GetQext();
     double GetQsca();
     double GetQabs();
@@ -210,14 +206,16 @@ namespace nmie {
 			             std::vector<double>& Tau);
     void calcAllPiTau(std::vector< std::vector<double> >& Pi,
 		              std::vector< std::vector<double> >& Tau);
-    void ScattCoeffs(std::vector<std::complex<double> >& an, std::vector<std::complex<double> >& bn); 
-    void ScattCoeffsLayerd();
-    void ScattCoeffsLayerdInit();
+    void ExtScattCoeffs(std::vector<std::complex<double> >& an, std::vector<std::complex<double> >& bn); 
+    void IntScattCoeffs();
+    void IntScattCoeffsInit();
 
     void fieldExt(const double Rho, const double Phi, const double Theta, const  std::vector<double>& Pi, const std::vector<double>& Tau, std::vector<std::complex<double> >& E, std::vector<std::complex<double> >& H);
 
     void fieldInt(const double Rho, const double Phi, const double Theta, const  std::vector<double>& Pi, const std::vector<double>& Tau, std::vector<std::complex<double> >& E, std::vector<std::complex<double> >& H);
     
+    bool areIntCoeffsCalc_ = false;
+    bool areExtCoeffsCalc_ = false;
     bool isMieCalculated_ = false;
     double wavelength_ = 1.0;
     double total_radius_ = 0.0;
@@ -232,7 +230,7 @@ namespace nmie {
     std::vector<double> theta_;
     // Should be -1 if there is no PEC.
     int PEC_layer_position_ = -1;
-    // Set nmax_ manualy with SetMaxTermsNumber(int nmax) or in ScattCoeffs(..)
+    // Set nmax_ manualy with SetMaxTermsNumber(int nmax) or in ExtScattCoeffs(..)
     // with Nmax(int first_layer);
     int nmax_ = -1;
     int nmax_used_ = -1;

+ 1 - 0
scattnlay.cpp

@@ -0,0 +1 @@
+#error Do not use this file, it is the result of a failed Cython compilation.