Fix forgotten ranks issue

src/binding/python/openpmd_api/pipe/__main__.py

@@ -154,12 +154,14 @@ def __init__(
         self,
         granularity_in,
         granularity_out,
-        inner_distribution=io.ByHostname(io.RoundRobin()),
+        inner_distribution,
+        local_rank,
     ):
         super().__init__()
         self.inner_distribution = inner_distribution
         self.granularity_in = granularity_in
         self.granularity_out = granularity_out
+        self.local_rank = local_rank
 
     def assign(self, assignment, in_ranks, out_ranks):
         if "in_ranks_inner" in dir(self):
@@ -209,6 +211,14 @@ def inner_rank_assignment(outer_assignment, hostname_to_hostgroup):
             out_ranks, out_hostname_to_hostgroup
         )
 
+        # we only care about the local host
+        local_host = self.out_ranks_inner[self.local_rank]
+        self.out_ranks_inner = {
+            rank: host
+            for rank, host in self.out_ranks_inner.items()
+            if host == local_host
+        }
+
         return self.inner_distribution.assign(
             assignment, self.in_ranks_inner, self.out_ranks_inner
         )
@@ -293,7 +303,7 @@ def distribution_strategy(dataset_extent,
         return IncreaseGranularity(
             granularity, 1,
             io.FromPartialStrategy(io.ByHostname(io.RoundRobin()),
-                                   io.DiscardingStrategy()))
+                                   io.DiscardingStrategy()), mpi_rank)
     elif strategy_identifier == 'all':
         return io.FromPartialStrategy(IncreaseGranularity(5), LoadAll(mpi_rank))
     elif strategy_identifier == 'roundrobin':
@@ -327,7 +337,7 @@ def __init__(self, infile, outfile, inconfig, outconfig, comm):
             hostinfo = io.HostInfo.MPI_PROCESSOR_NAME
             self.outranks = hostinfo.get_collective(self.comm)
             my_hostname = self.outranks[self.comm.rank]
-            self.outranks = {i: rank for i, rank in self.outranks.items() if rank == my_hostname}
+            self.outranks = {i: rank for i, rank in self.outranks.items()}
         else:
             self.outranks = {i: str(i) for i in range(self.comm.size)}