anchor.diff:      scalapack
       blas
       lapack
  -  ];
  +  ] ++ lib.optional enableElpa elpa;
   
     propagatedBuildInputs = [ mpi ];
     propagatedUserEnvPkgs = [ mpi ];
  
positive.code: 
    nativeBuildInputs = [ python3 which openssh makeWrapper pkg-config ];
    buildInputs = [
      elpa
      gfortran
      fftw
      gsl
  
negative.code: { lib, stdenv, fetchFromGitHub, python3, gfortran, blas, lapack
  , fftw, libint, libvori, libxc, mpi, gsl, scalapack, openssh, makeWrapper
  , libxsmm, spglib, which, pkg-config
  , enableElpa ? false
  , elpa
  } :
  
  let
  