From 29e97bdea2c22ffd618bbde0394740c81c27faf8 Mon Sep 17 00:00:00 2001
From: Peter Heywood <peethwd@gmail.com>
Date: Tue, 21 Nov 2023 17:00:55 +0000
Subject: [PATCH] Add detail::MPIEnsemble members for the group rank and size.
 Plus docstring changes

---
 .../flamegpu/simulation/detail/MPIEnsemble.h  | 19 ++++++++++++++++++-
 src/flamegpu/simulation/detail/MPIEnsemble.cu |  2 ++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/flamegpu/simulation/detail/MPIEnsemble.h b/include/flamegpu/simulation/detail/MPIEnsemble.h
index 692f41c05..3c3a46a45 100644
--- a/include/flamegpu/simulation/detail/MPIEnsemble.h
+++ b/include/flamegpu/simulation/detail/MPIEnsemble.h
@@ -30,8 +30,25 @@ class MPIEnsemble {
     };
 
  public:
+    /**
+     * The rank within the world MPI communicator
+     */
     const int world_rank;
+    /**
+     * The size of the world MPI communicator
+     */
     const int world_size;
+    /**
+     * The rank within the MPI shared memory communicator (i.e. the within the node)
+     */
+    const int group_rank;
+    /**
+     * The size of the MPI shared memory communicator (i.e. the within the node)
+     */
+    const int group_size;
+    /**
+     * The total number of runs to be executed (only used for printing error warnings)
+     */
     const unsigned int total_runs;
     /**
      * Construct the object for managing MPI comms during an ensemble
@@ -94,7 +111,7 @@ class MPIEnsemble {
      */
     static int queryMPISharedGroupRank();
     /**
-     * @return retrieve the number of mpi processes on the current shared memory region 
+     * @return retrieve the number of mpi processes on the current shared memory region
      */
     static int queryMPISharedGroupSize();
     /**
diff --git a/src/flamegpu/simulation/detail/MPIEnsemble.cu b/src/flamegpu/simulation/detail/MPIEnsemble.cu
index 68fe42f4a..6fb26f391 100644
--- a/src/flamegpu/simulation/detail/MPIEnsemble.cu
+++ b/src/flamegpu/simulation/detail/MPIEnsemble.cu
@@ -10,6 +10,8 @@ MPIEnsemble::MPIEnsemble(const CUDAEnsemble::EnsembleConfig &_config, const unsi
     : config(_config)
     , world_rank(queryMPIWorldRank())
     , world_size(queryMPIWorldSize())
+    , group_rank(queryMPISharedGroupRank())
+    , group_size(queryMPISharedGroupSize())
     , total_runs(_total_runs)
     , MPI_ERROR_DETAIL(AbstractSimRunner::createErrorDetailMPIDatatype()) { }