Mahti (mahti.csc.fi)

Note

These instructions are up-to-date as of September 2025.

Stable GPAW releases

Mahti has several versions of GPAW available as modules. You can load the most recent module with module load gpaw, and browse other available versions with module spider gpaw.

Currently the pre-installed modules have CPU support only. A manual (developer) installation is needed for GPU support.

Developer installation on Mahti

GPAW for CPUs (Python 3.11)

This section is for Python 3.11. See below for an older 3.9 version.

Do the following in a new terminal session.

# Move to installation directory of your choice
cd /projappl/project_.../$USER

# Use a specific Python installation
export python=/appl/spack/v023/views/gpaw-python-311/bin/python3.11

# Create virtual environment
$python -m venv --system-site-packages venv-gpaw-cpu

# The following will insert environment setup to the beginning of venv/bin/activate
cp venv-gpaw-cpu/bin/activate venv-gpaw-cpu/bin/activate.old
cat << EOF > venv-gpaw-cpu/bin/activate
module load gcc/14.2.0
module load openmpi/5.0.6
module load openblas/0.3.28-omp
module load fftw/3.3.10-mpi-omp
module load netlib-scalapack/2.2.0

# Set library and include paths for non-module dependencies (xc)
export LIBRARY_PATH=/appl/spack/v023/views/gpaw-python-311/lib64:/appl/spack/v023/views/gpaw-python-311/lib:\$LIBRARY_PATH
export LD_LIBRARY_PATH=/appl/spack/v023/views/gpaw-python-311/lib64:/appl/spack/v023/views/gpaw-python-311/lib:\$LD_LIBRARY_PATH
export CPATH=/appl/spack/v023/views/gpaw-python-311/include:\$CPATH

# Paths for libvdwxc separately. We use the v0.4.0 install from gcc-13.1.0 tree which was built for OpenMPI-4.
# Not ideal but works (ABIs are compatible)
export LIBRARY_PATH=/appl/spack/v020/install-tree/gcc-13.1.0/libvdwxc-0.4.0-5vlzlb/lib:\$LIBRARY_PATH
export LD_LIBRARY_PATH=/appl/spack/v020/install-tree/gcc-13.1.0/libvdwxc-0.4.0-5vlzlb/lib:\$LD_LIBRARY_PATH
export CPATH=/appl/spack/v020/install-tree/gcc-13.1.0/libvdwxc-0.4.0-5vlzlb/include:\$CPATH
EOF
cat venv-gpaw-cpu/bin/activate.old >> venv-gpaw-cpu/bin/activate

# Activate venv
source venv-gpaw-cpu/bin/activate

# Setup constraints for pip so that we don't accidentally override system provided packages
pip list --format=freeze | tee $(dirname $(which pip))/../constraints.txt

# Update pip, setuptools etc
pip install --upgrade pip setuptools packaging

# Clone GPAW development repository
git clone https://gitlab.com/gpaw/gpaw.git
cd gpaw

export GPAW_CONFIG=$(readlink -f doc/platforms/Linux/Mahti/siteconfig-mahti-cpu.py)

# Install GPAW. Leave the '-e' out if you don't want an editable install
rm -rf build _gpaw.*.so gpaw.egg-info
pip install --no-build-isolation --constraint $(dirname $(which pip))/../constraints.txt -v --log build-cpu.log -e .

The above gets siteconfig.py from the cloned Git repository. Alternatively, you can download it from here: siteconfig-mahti-cpu.py.

GPAW for CPUs (Python 3.9)

Note: Python 3.9 reached end-of-life in October 2025, and is not officially supported by GPAW anymore either. May not work with very recent development versions of GPAW.

Do the following in a new terminal session.

# Move to installation directory of your choice
cd /projappl/project_.../$USER

# Use a specific Python installation
export python=/appl/spack/v017/views/gpaw-python3.9/bin/python3.9

# Create virtual environment
$python -m venv --system-site-packages venv-gpaw-cpu

# The following will insert environment setup to the beginning of venv/bin/activate
cp venv-gpaw-cpu/bin/activate venv-gpaw-cpu/bin/activate.old
cat << EOF > venv-gpaw-cpu/bin/activate
module load gcc/11.2.0
module load openmpi/4.1.2
module load openblas/0.3.18-omp
module load fftw/3.3.10-mpi
module load netlib-scalapack/2.1.0
EOF
cat venv-gpaw-cpu/bin/activate.old >> venv-gpaw-cpu/bin/activate

# Activate venv
source venv-gpaw-cpu/bin/activate

# Update pip, setuptools etc
pip install --upgrade pip setuptools packaging

# Freeze the system-provided packages
pip freeze | tee $(dirname $(which pip))/../constraints.txt

# Clone GPAW development repository
git clone https://gitlab.com/gpaw/gpaw.git
cd gpaw

export GPAW_CONFIG=$(readlink -f doc/platforms/Linux/Mahti/siteconfig-mahti-cpu-39.py)

# Install GPAW, with a constraint to ensure we use system-provided packages.
# Leave the '-e' out if you don't want an editable install
rm -rf build _gpaw.*.so gpaw.egg-info
# Install, while forcing pip to ignore Python version requirements due to end of support for Python 3.9
pip install  --ignore-requires-python --no-build-isolation --constraint $(dirname $(which pip))/../constraints.txt -v --log build-cpu.log -e .

The above gets siteconfig.py from the cloned Git repository. Alternatively, you can download it from here: siteconfig-mahti-cpu-39.py.