Running metadynamics with PLUMED and metatensor-defined collective variables

[Luthaf]

Very work in progress, this will not even run on CI!

To build the example locally:

git clone https://github.com/lab-cosmo/plumed2 --branch conda-metatensor plumed-conda-metatensor
cd plumed-conda-metatensor

# install the dependencies provided by pip
pip install cython "metatensor-torch>=0.5.5"

# SETUP FLAGS following https://www.plumed.org/doc-master/user-doc/html/_m_e_t_a_t_e_n_s_o_r_m_o_d.html, 
# the code below should work on linux, when using pre-built from pip wheels

# export the location to all the libraries:
TORCH_CMAKE_PREFIX=$(python -c "import torch; print(torch.utils.cmake_prefix_path)")
TORCH_PREFIX=$(cd "$TORCH_CMAKE_PREFIX/../.." && pwd)
 
METATENSOR_CMAKE_PREFIX=$(python -c "import metatensor; print(metatensor.utils.cmake_prefix_path)")
METATENSOR_PREFIX=$(cd "$METATENSOR_CMAKE_PREFIX/../.." && pwd)
 
METATENSOR_TORCH_CMAKE_PREFIX=$(python -c "import metatensor.torch; print(metatensor.torch.utils.cmake_prefix_path)")
METATENSOR_TORCH_PREFIX=$(cd "$METATENSOR_TORCH_CMAKE_PREFIX/../.." && pwd)
TORCH_CPPFLAGS="-D_GLIBCXX_USE_CXX11_ABI=0"

TORCH_INCLUDES="-I$TORCH_PREFIX/include -I$TORCH_PREFIX/include/torch/csrc/api/include"
CPPFLAGS="$TORCH_INCLUDES $TORCH_CPPFLAGS -I$METATENSOR_PREFIX/include -I$METATENSOR_TORCH_PREFIX/include $CPPFLAGS"
 
LDFLAGS="-L$TORCH_PREFIX/lib -L$METATENSOR_PREFIX/lib -L$METATENSOR_TORCH_PREFIX/lib $LDFLAGS"
LDFLAGS="$LDFLAGS -Wl,-rpath,$TORCH_PREFIX/lib"
LDFLAGS="$LDFLAGS -Wl,-rpath,$METATENSOR_PREFIX/lib -Wl,-rpath,$METATENSOR_TORCH_PREFIX/lib"
LDFLAGS="$LDFLAGS -Wl,--disable-new-dtags"

./configure --enable-python --enable-libtorch --enable-metatensor --enable-modules=all LDFLAGS="$LDFLAGS" CPPFLAGS="$CPPFLAGS"

make -j

Then, set PLUMED_KERNEL in lj-crystal.py to [.....]/plumed-conda-metatensor/src/lib/libplumedKernel.so.

If you get an error about the GIL being held, copy [.....]/plumed-conda-metatensor/src/python/plumed.cpython-* to .nox/metatensor-plumed/lib/python3.*/site-packages/plumed.cpython-*.

This is blocked on the following PR to different tools used here:

• Build HEAD of v2.10 branch, enabling metatensor plumed/conda#5
• Do not hold Python's GIL when running commands plumed/plumed2#1129
• Allow to give settings to chemiscope.explore chemiscope#378