![output example](/doc/OutputExample.png)
**Output example:** Field distribution inside layered Si\Ag\Si sphere
and Poynting vector distribution in Ag sphere with powerflow lines
calculated with Scattnlay (scripts  field-SiAgSi-flow.py and
field-Ag-flow.py from example section as [revision](https://github.com/ovidiopr/scattnlay/commit/57c7261705a5776f78420c1f486e929517d5f584) ).

Discuss:
--------

Try to join our Gitter chat: [![Join the chat at https://gitter.im/scattnlay/Lobby](https://badges.gitter.im/scattnlay/Lobby.svg)](https://gitter.im/scattnlay/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
Fill the issue here: [Issues](https://github.com/ovidiopr/scattnlay/issues).

Stable releases
===============

- Version 2.0.1 (Jan 17, 2017). [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.248729.svg)](https://doi.org/10.5281/zenodo.248729)
- Version 2.0.0 (Apr 1, 2016).
- Version 1.0.0 (Nov 22, 2014).

How to use scattnlay
====================

**Table of contents:**
- [Mie theory calculator web application](#mie-theory-calculator-web-application)
- [Compile code](#compile-code)
- [Binary install](#binary-install)
- [Use](#use)
- [Papers](#papers)
- [Acknowledgment](#acknowledgment)
- [License](#license)

Mie theory calculator web application
---------------

Limited web version is available at https://physics.ifmo.ru/mie/


Compile Code
-------------
To compile the source you will need a C++11 capable compiler. To use
optional MultiPrecision feature you need to install
Boost.Multiprecision library (package names are given in Ubuntu\Debian
notation):

 - **libboost-all-dev (>= 1.58.0)**

To compile the Python extension you need [NumPy](http://www.numpy.org/):

 - **python-numpy (>= 1.0)**
 - **python-all-dev (any version)**
 - **python-numpy-dev (any version)**
 - **pybind11 (any version)**

And to compile the Debian package you need some tools:

 - **debhelper (>=7.0.0)**
 - **dh-python (any version)**
 - **cdbs (>= 0.4.49)**

Compilation options

 - **make source** - Create source package for Python extension
 - **make ext** - Create Python extension using C++ code
 - **make install** - Install Python extension on local system
 - **make rpm** - Generate a rpm package for Python extension
 - **make deb** - Generate a deb package for Python extension
 - **make standalone** - Create standalone programs (scattnlay and fieldnlay)
 - **make clean** - Delete temporal files

There are also an experimental CMake project and it is possible to compile into JavaScript module (using Emscripten compiler).

Python module

To build and install Python module run from the source code directory:

```bash
pip install . --user
```

Binary install
--------------

Binary files for Ubuntu and derivative distributions can be found at
[Launchpad](https://launchpad.net/~ovidio/+archive/ubuntu/scattering/+packages)
To install it you must configure the repository:
``` bash
sudo add-apt-repository ppa:ovidio/scattering
sudo apt update
```
and then you simply install the package:
``` bash
sudo apt install python-scattnlay
```
You can also install it from PyPi via
```bash
sudo pip install python-scattnlay
```

You can also ```git clone``` and ```pip install -e .``` to develop python package.

Use
----

1. Python library
  * Use scattnlay directly
  
  ```python
from scattnlay import scattnlay, fieldnlay
...
x = ...
m = ...
coords = ...
terms, Qext, Qsca, Qabs, Qbk, Qpr, g, Albedo, S1, S2 = scattnlay(x, m)
terms, E, H = fieldnlay(x, m, coords)
...
  ```
  
  * Execute some of the test scripts (located in the folder 'tests/python')
          Example:
		  
  ```bash
./test01.py
  ```
  
2. Standalone program
  * Execute scattnlay directly:

  ```bash
scattnlay -l Layers x1 m1.r m1.i [x2 m2.r m2.i ...] [-t ti tf nt] [-c comment]
  ```

  * Execute fieldnlay directly:

  ```bash
fieldnlay -l Layers x1 m1.r m1.i [x2 m2.r m2.i ...] -p xi xf nx yi yf ny zi zf nz [-c comment]
  ```

  * Execute some of the test scripts (located in the folder 'tests/shell'):

  ```bash
./test01.sh > test01.csv
  ```
  
3. C++ library

Scattnlay "Hello world!" example:

```C++
    try {
      nmie::MultiLayerMieApplied<double> multi_layer_mie; 
      multi_layer_mie.AddTargetLayer(core_width, index_Si);
      multi_layer_mie.AddTargetLayer(inner_width, index_Ag);
      multi_layer_mie.AddTargetLayer(outer_width, index_Si);
      multi_layer_mie.SetWavelength(WL);
      multi_layer_mie.RunMieCalculation();
      double Qabs = multi_layer_mie.GetQabs();
      printf("Qabs = %g\n", Qabs);
    } catch( const std::invalid_argument& ia ) {
      // Will catch if  multi_layer_mie fails or other errors.
      std::cerr << "Invalid argument: " << ia.what() << std::endl;
      return -1;
    }
```

The complete `example-minimal.cc` and a bit more complicated
`example-get-Mie.cc` can be found in example directory along with
`go-cc-examples.sh` script with build commands.

`example-get-Mie.cc` can be compiled using double precision or
multiple precision (just include `-DMULTI_PRECISION=200` to use 200
digits for calculations). 

Related papers
--------------

1. O. Peña and U. Pal, "Scattering of electromagnetic radiation by a
   multilayered sphere," Comput. Phys. Commun. 180, 2348-2354 (2009).
   http://dx.doi.org/10.1016/j.cpc.2009.07.010

2. K. Ladutenko, O. Peña-Rodríguez, I. Melchakova, I. Yagupov and P. Belov,
   "Reduction of scattering using thin all-dielectric shells designed by
   stochastic optimizer," J. Appl. Phys. 116, 184508 (2014).
   http://dx.doi.org/10.1063/1.4900529

3. K. Ladutenko, P. Belov, O. Peña-Rodríguez, A. Mirzaei, A. Miroshnichenko
   and I. Shadrivov, "Superabsorption of light by nanoparticles,"
   Nanoscale 7, 18897-18901 (2015).
   http://dx.doi.org/10.1039/C5NR05468K

4. K. Ladutenko, U. Pal, A. Rivera, and O. Peña-Rodríguez, "Mie calculation
   of electromagnetic near-field for a multilayered sphere,"
   Comp. Phys. Comm. 214, 225-230 (2017).
   http://dx.doi.org/j.cpc.2017.01.017

Acknowledgment
--------------

We expect that all publications describing work using this software,
or all commercial products using it, cite at least one of the following references:
> [1] O. Peña and U. Pal, "Scattering of electromagnetic radiation
>     by a multilayered sphere," Computer Physics Communications,
>     vol. 180, Nov. 2009, pp. 2348-2354.
>
> [2] K. Ladutenko, U. Pal, A. Rivera and O. Peña-Rodríguez, "Mie calculation
>     of electromagnetic near-field for a multilayered sphere,"
>     Computer Physics Communications, vol. 214, May 2017, pp. 225-230.


License
-------

GPL v3+