Installation

Prerequisites

Dependency	Notes
MPI (OpenMPI / MPICH)	mpicc and mpicxx must be on PATH
libfabric	Required for the RDMA backends (method=1 and method=2)
Python ≥ 3.9
NumPy, mpi4py, Cython	Python build dependencies
PyTorch (optional)	For pyddstore.torch and GPU buffers (CUDA or ROCm build)

Building and installing

# Install Python build dependencies
pip install numpy mpi4py Cython

# Build in-place (use with PYTHONPATH=$PWD/src:$PYTHONPATH)
CC=mpicc CXX=mpicxx python setup.py build_ext --inplace

# Or install into the active virtual environment
CC=mpicc CXX=mpicxx pip install .
CC=mpicc CXX=mpicxx pip install ".[torch]"     # also pulls PyTorch, for pyddstore.torch

# Or install in editable/development mode
CC=mpicc CXX=mpicxx pip install -e .

# Or install directly from GitHub
CC=mpicc CXX=mpicxx pip install git+https://github.com/ORNL/DDStore.git

To build against the packages already in the current environment (e.g. an mpi4py built against Cray MPICH) instead of letting pip fetch fresh build dependencies into an isolated build environment, disable build isolation:

CC=cc CXX=CC pip install --no-build-isolation --no-deps -e .

If that fails with ModuleNotFoundError: No module named 'distutils.msvccompiler' (newer setuptools combined with an older system NumPy, e.g. cray-python/3.11.7 on Frontier), point setuptools at the standard-library distutils for the build:

SETUPTOOLS_USE_DISTUTILS=stdlib CC=cc CXX=CC pip install --no-build-isolation --no-deps -e .

The package is pyddstore (compiled core pyddstore._core, plus pyddstore.torch). After updating from a 1.x checkout, rebuild; an old src/pyddstore.cpython-*.so or src/pyddstore.cpp left behind is unused and can be deleted (the build warns about them).

Editable and in-place builds keep the generated src/pyddstore/_core.cpp in the checkout, shared by every environment that builds from it. setup.py regenerates it whenever the NumPy major version differs from the previous build’s, because a file generated against NumPy 2 doesn’t compile against NumPy 1.x headers.