>>Unfortunately, this is not possible. Graph-tool uses the CPython C API
>>(via boost-python) which is not implemented by pypy.

>Pypy does have support, sometimes with performance problems, for most of the Cpython APIs

Indeed, the situation may not be hopeless.  IIUC, With PyPy’s C API compatibility layer (cpyext), many compiled extensions can be built for PyPy with minimal changes (or perhaps none at all?).  The conda-forge project has been methodically adding PyPy support to many of its packages, including numpy, scipy, matplotlib, etc.  Just recently, their package for boost itself was updated for PyPy support[1]. On my machine, I can build a “hello world” extension with boost-python and run it with PyPy, without any special magic. (See attached.)

In the coming months, *maybe* all of graph-tool’s dependencies will be supported in conda-forge.  But that won’t happen on its own.  If this is important to you, please consider assisting with the following PRs, which currently fail:

https://github.com/conda-forge/pycairo-feedstock/pull/21

https://github.com/conda-forge/pygobject-feedstock/pull/27

I think those are the only remaining obstacles to at least attempting to build a graph-tool PyPy package. (I’m not sure about the glib feedstock.)

I’m not a PyPy user (yet?) so I can’t make any promises about my own commitment to this effort.  And I certainly can’t comment on what will happen if it turns out patches are required in the graph-tool source code itself.  Nonetheless, I think there’s *hope* that a sufficiently motivated PyPy user could make progress on this.  If you decide to try it, feel free to ping me on relevant github threads (@stuarteberg).

Best,

Stuart

[1]: https://github.com/conda-forge/boost-feedstock/pull/110#issuecomment-763940556