MULTEM

Introduction

MULTEM is a collection of routines written in C++ with CUDA to perform accurate and fast multislice simulations for different TEM experiments as: HRTEM, STEM, ISTEM, ED, PED, CBED, ADF-TEM, ABF-HC, EFTEM and EELS. It is developed by Ivan Lobato ([email protected]).

Currently, there are three supported ways to use MULTEM:

• C++: using the library itself
• Matlab: using the mex interface
• GUI: using the user graphical interface

The library is under heavy development and subject to change. The Matlab interface is the recommended way for researchers.

Remarks

In order to use the GPU capability of MULTEM, you need a Nvidia Graphic card with compute capability greater than 2.0 and CUDA 8.0 installed in your operating system. You can check the compute capability of your graphic card using the following nvidia website: https://developer.nvidia.com/cuda-gpus.

Using precompile GUI interface

The precompile GUI interface is only available for Windows operating system.

• Go to https://github.com/Ivanlh20/MULTEM/releases and download MULTEM_binary.7z.
• Execute vc_redist.x64.exe located in gui_bin folder.
• Execute multem.exe.

Using precompile mexfiles for Matlab

The precompile mexfiles are only available for Windows operating system.

• Go to https://github.com/Ivanlh20/MULTEM/releases and download MULTEM_binary.7z.
• Execute vc_redist.x64.exe located in mex_bin folder.
• Add to the Matlab path the following folders: crystalline_materials, matlab_functions and mex_bin.
• Run the examples located in 'mex_examples_multem'.

Building MULTEM for Matlab

The following steps work using Matlab R2017a and CUDA 8.0. It assumes that Visual studio 2015 professional, g++4.9 or Clang(Xcode 8.x) compiler is installed in your operating system. Additionally, Multem also requires fftw3, blas and lapack libraries.

• First of all, you have to set a C++ compiler to Matlab by executing the following comand: mex -setup cpp. Be aware that Matlab 2017a only support the above compilers.
• Then add to the Matlab path the following folders: crystalline_materials, matlab_functions and mex_bin.
• Run the compile_mex_multem.m script. This will create the required executable files to run the examples.
• Run the examples located in mex_examples_multem.

Troubleshooting

• If MULTEM do not compile with the above procedures, one of the following procedures might fix it

  for Windows:

  • Verify the installation of Visual studio 2015 professional.
  • Verify the installation of Cuda 8.0 (https://developer.nvidia.com/cuda-downloads).

  for Linux:

  • Verify that gcc-4.9 and g++4.9 are the default compilers installed in your operating system. In Ubuntu, it can be installed by executing the following commands:

    • sudo add-apt-repository ppa:ubuntu-toolchain-r/test
    • sudo apt-get update
    • sudo apt-get install gcc-4.9 g++-4.9
    • sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.9 60 --slave /usr/bin/g++ g++ /usr/bin/g++-4.9

  • Verify the correct installation of Cuda 8.0 (https://developer.nvidia.com/cuda-downloads).

  • Verify the installation of fftw3 libraries. In Ubuntu, it can be installed by executing the following command:

    • sudo apt-get install libfftw3-dev libfftw3-doc

  • Verify the installation of blas and lapack libraries. In Ubuntu, it can be installed by executing the following command:

    • sudo apt-get install libblas-dev liblapack-dev

• Verify the installation path of cuda 8.0, fftw3, blas and lapack. Their installation paths should be specified in the MEX.m file located at matlab_functions.

Please cite MULTEM in your publications if it helps your research:

@article{LVAV16_1,
  Author = {I.Lobato and S.Van Aert and J.Verbeeck},
  Journal = {Ultramicroscopy},
  Title = {Progress and new advances in simulating electron microscopy datasets using MULTEM},
  Year = {2016},
  volume  = {168},
  pages   = {17-27}      
}

 @article{LD15_2,
  Author = {I. Lobato and D. Van Dyck},
  Journal = {Ultramicroscopy},
  Title = {MULTEM: A new multislice program to perform accurate and fast electron diffraction and imaging simulations using Graphics Processing Units with CUDA},
  Year = {2015},
  volume  = {156},
  pages   = {9-17}      
} 

if you use our parameterization of the electronscattering factors, please cite the following article:

@Article{LD14_1,
Title = {{An accurate parameterization for the scattering factors, electron densities and electrostatic potentials for neutral atoms that obey all physical constraints}},
Author = {I. Lobato and D. Van Dyck},
Journal = {Acta Crystallographica Section A},
Year = {2014},
Pages = {636-649},
Volume = {70}
}