Interface to Libint by E. Valeev¶
Code author: Edward F. Valeev and Justin T. Fermann
Section author: Lori A. Burns
PSI4, particularly libmints utterly relies upon the Libint library developed by E. Valeev from early roots by J. Fermann. Libint requires no additional licence, downloads, or configuration. Conversely, PSI4 cannot build without Libint.
As of Nov 2020 or release v1.4, PSI4 uses Libint2, not Libint1. Compared to many other open-source QC codes, PSI4 requires a separate Libint compilation with a different integrals ordering. See notes at top of https://github.com/psi4/psi4/blob/master/external/upstream/libint2/CMakeLists.txt
Libint is available as a conda package for Linux and macOS (and Windows, through the Ubuntu shell).
If using the PSI4 binary, Libint has already been installed alongside.
If using PSI4 built from source, and anaconda or miniconda has already been installed (instructions at Quick Installation), Libint can be obtained through
conda install libint -c psi4. Then, hint its location with CMAKE_PREFIX_PATH, and rebuild PSI4 to detect Libint and activate dependent code.
To remove a conda installation,
conda remove libint.
How to configure Libint for building Psi4¶
Role and Dependencies
Role — In PSI4, Libint is a library that provides essential two-body molecular integrals over Gaussian functions.
Downstream Dependencies — PSI4 \(\Leftarrow\) Libint
Upstream Dependencies — Libint \(\Leftarrow\) None
CMAKE_PREFIX_PATH — CMake list variable to specify where pre-built dependencies can be found. For Libint, set to an installation directory containing
Libint_DIR — CMake variable to specify where pre-built Libint can be found. Set to installation directory containing
CMAKE_DISABLE_FIND_PACKAGE_Libint — CMake variable to force internal build of Libint instead of detecting pre-built
CMAKE_INSIST_FIND_PACKAGE_Libint — CMake variable to force detecting pre-built Libint and not falling back on internal build
MAX_AM_ERI — CMake variable to specify minimum highest angular momentum built or detected
Link against pre-built
>>> cmake -DCMAKE_PREFIX_PATH=/path/to/libint/root
>>> cmake -DLibint_DIR=/path/to/libint/configdir
Build bundled despite pre-built being detectable
>>> cmake -DCMAKE_PREFIX_PATH=/path/to/unwanted/libint/root/and/wanted/other/dependencies/root -DCMAKE_DISABLE_FIND_PACKAGE_Libint=ON
Build bundled shared library with AM=6
>>> cmake -DMAX_AM_ERI=6 -DBUILD_SHARED_LIBS=ON