anchor.diff:                      resolution=resolution)
       sim.run(until=200)
       EOF
  +
  +    ${mpi}/bin/mpiexec -np 2 python3 test.py
     '';
   
     meta = with lib; {
  
positive.code: { stdenv, lib, buildPythonPackage, fetchFromGitHub, autoreconfHook, pkg-config
  , gfortran, mpi, blas, lapack, fftw, hdf5-full, swig, gsl, harminv, libctl
  , libGDSII, openssh, guile
  # Python
  , python, numpy, scipy, matplotlib, h5py, cython, autograd, mpi4py
  } :
  
  buildPythonPackage rec {
  
negative.code:     blas
      lapack
      fftw
      hdf5-mpi
      harminv
      libctl
      libGDSII
  