Compiled Fortran addons to pysisyphus, that would be too slow in pure Python. The Fortran code is interfaced by Cython functions that are easily called from Python.
When using procedures from this project that involve handling of bigger matrices please execute
ulimit -s unlimitedin your shell; otherwise the code will segfault.
This project provides fast and OMP-parallel Fortran procedures for the following tasks:
diabatization/: Construction of the Coulomb-Tensor in the basis of adiabatic electronic states using density fitting. Required for Edmiston-Ruedenberg diabatization.gdma/: Evaluation of the density on a given DFT grid, as required for GDMA.grid/: Evaluation of (multiple) densities on a given cubic grid, as required for the calculation of .cub files.std/: 2-electron integral tensors for eXact simplified TD-DFT w/ density fitting.
Code found in common/ includes basic driver procedures to calculate various integrals, to set up integral screeners as well as
simple wrappers for various linear algebra procedures from LAPACK. The intor/ directory contains procedures for benchmarking the performance of the density fitting integrals and their associated screeners.
As this project contains mainly Fortran code it is built with meson and meson-python. The required integral code
for the density fitting (3-center-2-electron- and 2-center-2-electron-integrals), as well as selected 4-center-2-electron-integrals (AB|AB) for Schwarz-screening are generated on-the-fly at build-time by invoking sympleints, which must be available/installed.
By default, selected 4c2e-integrals are built up to (GG|GG) and 3c2e- and 2c2e integrals for density fitting are built up to (GG|H) and (H|H).
Maximum angular momenta for integral generation can be controlled with the -Dlmax and -Dlauxmax options.
pysisyphus-addons utilizes various BLAS and LAPACK procedures, so both libraries must be available. Different implementations can be selected via -Dblas=[blas|openblas] and -Dlapack=[lapack|openblas].
A newer GCC version, e.g. 13+, is required for building this project.
Below you can find an example to check if pysisyphus-addons can be built on your system. Depending on your setup you'll have to adapt the compiler version and the path to the OpenBLAS pkgconfig-file, as well as the number of cores when building -j12.
PKG_CONFIG_PATH=/home/johannes/programme/openblas/lib/pkgconfig \
FC=gfortran-13 CC=gcc-13 CXX=g++-13 \
python -m build \
-Csetup-args=-Dlmax=2 \
-Csetup-args=-Dlauxmax=2 \
-Csetup-args=-Dblas=openblas \
-Csetup-args=-Dlapack=openblas \
-Ccompile-args="-j12"For an actually useful production build -Dlmax and -Dlauxmax should be kept at the default values. At their default values, integral generation currently takes about 1 hour and actually compiling them will also take about 1 hour and will require a machine with at least 30 GB free memory.
On its own pysisyphus-addons is not useful, but it is called by pysisyphus with the required inputs.