Multithreaded calcGrains with mtex

The calcGrains method of MTex can use jcvoronoi to speed up the grain reconstruction process via multithreading and a faster library. Depending on the operating system this may require though that jcvoronoi needs to be compiled locally so that the its mex extension is overwritten. A how-to for Ubuntu 24.04. reads as follows:

Assure to have installed build-essentials and a C/C++ compiler e.g. the GNU gcc/g++ compiler

sudo apt-get update
sudo apt-get install build-essentials

Start Matlab with the specific version of the libstdc++.so.6 that was used for compiling the mexa64 file (here assuming default Linux installation location of Matlab)

LD_PRELOAD=/lib/x86_64-linux-gnu/libstdc++.so.6 /usr/local/MATLAB/R2024b5/bin/matlab

See respective references for further details:

• https://de.mathworks.com/matlabcentral/answers/1907290-how-to-manually-select-the-libstdc-library-to-use-to-resolve-a-version-glibcxx_-not-found
• https://de.mathworks.com/matlabcentral/answers/643300-why-do-i-receive-the-error-libstdc-so-6-version-glibcxx_3-4-22-not-found-when-trying-to-star
• https://datalowe.com/post/matlab-mex-files/

In Matlab compile jcvoronoi

# navigate in Matlab to `pynxtools-microstructure/src/pynxtools_microstructure/mtex/extern/jcvoronoi`
# compile in Matlab `mex jcvoronoi_mex.cpp`

Move that jcvoronoi_mex.mexa64 file into the mex directory replacing the existent one

# `pynxtools-microstructure/src/pynxtools_microstructure/mtex/mex`

Warning

Depending on the compiler on the target system, this mexa64 file might be system-specific.