LIBINT¶

Overview¶

For CP2K 6.1 (and earlier), LIBINT 1.1.x is required (1.2.x, 2.x, or any later version cannot be used). For CP2K 7.x and onwards, LIBINT 2.5 (or later) is needed.

Please make the Intel Compiler available on the command line. This depends on the environment. For instance, many HPC centers rely on module load.

source /opt/intel/compilers_and_libraries_2020.4.304/linux/bin/compilervars.sh intel64

Note: CP2K 6.1 (and earlier) depends on LIBINT 1.1.x and a newer version of LIBINT cannot be used! CP2K 7.x (and later) rely on LIBINT 2.5 (or later) and cannot use the preconfigured library as provided on LIBINT's home page.

Version 2.5 (and later)¶

LIBINT generates code according to a configuration and an extent that is often specific to the application. The downloads from LIBINT's home page are not configured for CP2K and hence cannot be used. Please download (take "lmax-6" if unsure), unpack LIBINT, and make the configure wrapper scripts available in LIBINT's root folder.

To just determine the download-URL of the latest version (a suitable variant can be "lmax-6"):

curl -s https://api.github.com/repos/cp2k/libint-cp2k/releases/latest \
| grep "browser_download_url" | grep "lmax-6" \
| sed "s/..*: \"\(..*[^\"]\)\".*/\1/"

To download the lmax6-version right away, run the following command:

curl -s https://api.github.com/repos/cp2k/libint-cp2k/releases/latest \
| grep "browser_download_url" | grep "lmax-6" \
| sed "s/..*: \"\(..*[^\"]\)\".*/url \1/" \
| curl -LOK-

Note: A rate limit applies to GitHub API requests of the same origin. If the download fails, it can be worth trying an authenticated request by using a GitHub account (-u "user:password").

To unpack the archive and to download the configure wrapper (lmax6-version is assumed):

tar xvf libint-v2.6.0-cp2k-lmax-6.tgz
cd libint-v2.6.0-cp2k-lmax-6

wget --content-disposition --no-check-certificate https://github.com/hfp/xconfigure/raw/master/configure-get.sh
chmod +x configure-get.sh
./configure-get.sh libint

There are spurious issues about specific target flags requiring a build-system able to execute compiled binaries. To avoid cross-compilation (not supported here), please rely on a build system that matches the target system. For example, to configure and make for an Intel Xeon Scalable processor such as "Cascadelake" or "Skylake" server ("SKX"):

make distclean
./configure-libint-skx.sh
make -j; make install

Make sure to run make distclean before reconfiguring a different variant, e.g., GNU and Intel variant. Further, for different targets (instruction set extensions) or different compilers, the configure-wrapper scripts support an additional argument ("default" is the default tagname):

./configure-libint-hsw.sh tagname

As shown above, an arbitrary "tagname" can be given (without editing the script). This might be used to build multiple variants of the LIBINT library.

Version 1.x¶

Download and unpack LIBINT and make the configure wrapper scripts available in LIBINT's root folder. Please note that the "automake" package is a prerequisite.

wget --content-disposition --no-check-certificate https://github.com/evaleev/libint/archive/release-1-1-6.tar.gz
tar xvf release-1-1-6.tar.gz
cd libint-release-1-1-6

wget --content-disposition --no-check-certificate https://github.com/hfp/xconfigure/raw/master/configure-get.sh
chmod +x configure-get.sh
./configure-get.sh libint

For example, to configure and make for an Intel Xeon E5v4 processor (formerly codenamed "Broadwell"):

make distclean
./configure-libint-hsw.sh
make -j; make install

The version 1.x line of LIBINT does not support to cross-compile for an architecture. If cross-compilation is necessary, one can rely on the Intel Software Development Emulator (Intel SDE) to compile LIBINT for targets, which cannot execute on the compile-host.

/software/intel/sde/sde -knl -- make

To speed-up compilation, "make" might be carried out in phases: after "printing the code" (c-files), the make execution continues with building the object-file where no SDE needed. The latter phase can be sped up by interrupting "make" and executing it without SDE. The root cause of the entire problem is that the driver printing the c-code is (needlessly) compiled using the architecture-flags that are not supported on the host.

References¶

https://github.com/cp2k/cp2k/blob/master/INSTALL.md#2g-libint-optional-enables-methods-including-hf-exchange
https://github.com/evaleev/libint/releases/tag/release-1-1-6
https://github.com/cp2k/libint-cp2k/releases/latest