The only requirement for pygram11 is NumPy. All installation methods will ensure that numpy is installed. If you install binaries from conda-forge or PyPI, OpenMP acceleration is enabled.

Extras for Source Builds

When building from source, all you need is a C++ compiler with C++11 support. The script will test to see if OpenMP is available during compilation and linking of the backend extenstion module. Most Linux distributions with relatively modern GCC versions should provide OpenMP automatically (search the web to see how to install OpenMP from your distribution’s package manager). On macOS you’ll want to install libomp from Homebrew to use OpenMP with the Clang compiler shipped with macOS.

You can use pygram11 without OpenMP, but you might want to try fast-histogram if you just need to compute fixed bin histograms (see the benchmarks). If you’re here for variable width histograms or the sum-of-weights-squared first class citizenry or the multiple weight variation histograms - I think you’ll still find pygram11 useful.

Install Options


$ pip install pygram11


Installations from conda-forge provide a build that used OpenMP.

$ conda install pygram11 -c conda-forge


On macOS the OpenMP libraries from LLVM (libomp) and Intel (libiomp) can clash if your conda environment includes the Intel Math Kernel Library (MKL) package distributed by Anaconda. You may need to install the nomkl package to prevent the clash (Intel MKL accelerates many linear algebra operations, but does not impact pygram11):


$ pip install git+


If installing from source on macOS 10.14 or later, you may have to prepend the pip command with MACOSX_DEPLOYMENT_TARGET=10.x, where x is your macOS minor version number. (This may be required for conda environments, because the Python distribution from Anaconda for macOS is built with an older macOS SDK).

$ MACOSX_DEPLOYMENT_TARGET=10.14 pip install git+