I thought I would broaden out the discussion Henning and I have been having. I have managed to get http://hackage.haskell.org/package/blas-ffi http://hackage.haskell.org/package/blas-ffi to build under nix. Ideally we would like cabal2nix to do this automatically for us. We can do this if We use openblas rather than blas. Replace `PkgConfig-Depends: blas` with `PkgConfig-Depends: lapack (as the lapack derivation in nix generates a blas.pc) in the cabal file. Fix nix to generate .pc files for blas - I don’t know the consequences of doing this but I can’t see any downside. Does anyone have any views on what might be the best approach? Dominic Steinitz dominic@steinitz.org http://idontgetoutmuch.org Twitter: @idontgetoutmuch

Begin forwarded message:

From: dominic@steinitz.org Subject: Getting blas-ffi to build under nix Date: 28 August 2019 at 13:31:45 BST To: Henning Thielemann

Hi Henning,

I think there are 3 options (in nix - they may not work elsewhere)

Use openblas rather than blas Replace `PkgConfig-Depends: blas` with `PkgConfig-Depends: lapack` Fix nix to generate .pc files for blas (it does this for openblas and lapack, the latter also generates a blas.pc file

I don’t have a strong preference but I think I’d go for using openblas. I can send a patch but of course it’s a 1 line change so maybe you could just do it yourself and release a new version to hackage?

Dominic Steinitz dominic@steinitz.org mailto:dominic@steinitz.org http://idontgetoutmuch.org http://idontgetoutmuch.org/ Twitter: @idontgetoutmuch