make_resume_file() incompatible with MPI (#101)

* no idea why recvbuf.dtype was int, and is only not empty for rank 0

* add optional dependency fortranformat for cube_samples

* minimal changed to pyproject toml to get optional dependencies to work

* toml typo

* version bump

* revert changes to pyproject.toml

---------

Co-authored-by: Will Handley <wh260@cam.ac.uk>

pypolychord/polychord.py

@@ -258,16 +258,16 @@ def make_resume_file(settings, loglikelihood, prior):
  sendbuf = np.array(lives).flatten()
  sendcounts = np.array(comm.gather(len(sendbuf)))
  if rank == 0:
- recvbuf = np.empty(sum(sendcounts), dtype=int)
+ recvbuf = np.empty(sum(sendcounts))
  else:
  recvbuf = None
  comm.Gatherv(sendbuf=sendbuf, recvbuf=(recvbuf, sendcounts), root=0)
 
- lives = np.reshape(sendbuf, (len(settings.cube_samples), len(lives[0])))
- else:
- lives = np.array(lives)
-
  if rank == 0:
+ if MPI:
+ lives = np.reshape(recvbuf, (len(settings.cube_samples), len(lives[0])))
+ else:
+ lives = np.array(lives)
  with open(resume_filename,"w") as f:
  def write(var):
  var = np.atleast_1d(var)