ENH: more consistent naming of MPI reductions

- combineReduce     (older: combineAllGather)
- listCombineReduce (older: listCombineAllGather)
- mapCombineReduce  (older: mapCombineAllGather)

src/OpenFOAM/db/IOstreams/Pstreams/Pstream.H

@@ -202,13 +202,14 @@ public:
             const label comm = UPstream::worldComm
         );
 
-        //- Gather data, applying \c cop to inplace combine \c value
+        //- Reduce inplace (cf. MPI Allreduce)
+        //- applying \c cop to inplace combine \c value
         //- from different processors.
         //- After completion all processors have the same data.
         //  Uses the specified communication schedule.
         //  Wraps combineGather/broadcast (may change in the future).
         template<class T, class CombineOp>
-        static void combineAllGather
+        static void combineReduce
         (
             const List<commsStruct>& comms,
             T& value,
@@ -217,19 +218,33 @@ public:
             const label comm = UPstream::worldComm
         );
 
-        //- Gather data, applying \c cop to inplace combine \c value
+        //- Reduce inplace (cf. MPI Allreduce)
+        //- applying \c cop to inplace combine \c value
         //- from different processors.
         //- After completion all processors have the same data.
         //  Uses linear/tree communication.
         //  Wraps combineGather/broadcast (may change in the future).
         template<class T, class CombineOp>
+        static void combineReduce
+        (
+            T& value,
+            const CombineOp& cop,
+            const int tag = UPstream::msgType(),
+            const label comm = UPstream::worldComm
+        );
+
+        //- Same as Pstream::combineReduce
+        template<class T, class CombineOp>
         static void combineAllGather
         (
             T& value,
             const CombineOp& cop,
             const int tag = UPstream::msgType(),
             const label comm = UPstream::worldComm
-        );
+        )
+        {
+            Pstream::combineReduce(value, cop, tag, comm);
+        }
 
 
     // Combine variants working on whole List at a time.
@@ -256,16 +271,15 @@ public:
 
         //- After completion all processors have the same data.
         template<class T, class CombineOp>
-        static void listCombineAllGather
+        static void listCombineReduce
         (
-            const List<commsStruct>& comms,
             List<T>& values,
             const CombineOp& cop,
-            const int tag,
+            const int tag = UPstream::msgType(),
-            const label comm
+            const label comm = UPstream::worldComm
         );
 
-        //- After completion all processors have the same data.
+        //- Same as Pstream::listCombineReduce
         template<class T, class CombineOp>
         static void listCombineAllGather
         (
@@ -273,7 +287,10 @@ public:
             const CombineOp& cop,
             const int tag = UPstream::msgType(),
             const label comm = UPstream::worldComm
-        );
+        )
+        {
+            Pstream::listCombineReduce(values, cop, tag, comm);
+        }
 
 
     // Combine variants working on whole map at a time.
@@ -299,19 +316,23 @@ public:
             const label comm = UPstream::worldComm
         );
 
-
+        //- Reduce inplace (cf. MPI Allreduce)
+        //- applying \c cop to inplace combine map \c values
+        //- from different processors.
+        //- After completion all processors have the same data.
+        //  Uses the specified communication schedule.
+        //  Wraps mapCombineGather/broadcast (may change in the future).
         //- After completion all processors have the same data.
         template<class Container, class CombineOp>
-        static void mapCombineAllGather
+        static void mapCombineReduce
         (
-            const List<commsStruct>& comms,
             Container& values,
             const CombineOp& cop,
-            const int tag,
+            const int tag = UPstream::msgType(),
-            const label comm
+            const label comm = UPstream::worldComm
         );
 
-        //- After completion all processors have the same data.
+        //- Same as Pstream::mapCombineReduce
         template<class Container, class CombineOp>
         static void mapCombineAllGather
         (
@@ -319,7 +340,10 @@ public:
             const CombineOp& cop,
             const int tag = UPstream::msgType(),
             const label comm = UPstream::worldComm
-        );
+        )
+        {
+            Pstream::mapCombineReduce(values, cop, tag, comm);
+        }
 
 
     // Gather/scatter keeping the individual processor data separate.
@@ -347,19 +371,6 @@ public:
             const label comm = UPstream::worldComm
         );
 
-        //- Gather data, but keep individual values separate.
-        //- Uses the specified communication schedule.
-        //  After completion all processors have the same data.
-        //  Wraps gatherList/scatterList (may change in the future).
-        template<class T>
-        static void allGatherList
-        (
-            const List<commsStruct>& comms,
-            List<T>& values,
-            const int tag,
-            const label comm
-        );
-
         //- Gather data, but keep individual values separate.
         //- Uses linear/tree communication.
         //  After completion all processors have the same data.

src/OpenFOAM/db/IOstreams/Pstreams/PstreamCombineGather.C

@@ -255,13 +255,19 @@ void Foam::Pstream::combineScatter
     #ifndef Foam_Pstream_scatter_nobroadcast
     Pstream::broadcast(value, comm);
     #else
-    combineScatter(UPstream::whichCommunication(comm), value, tag, comm);
+    Pstream::combineScatter
+    (
+        UPstream::whichCommunication(comm),
+        value,
+        tag,
+        comm
+    );
     #endif
 }
 
 
 template<class T, class CombineOp>
-void Foam::Pstream::combineAllGather
+void Foam::Pstream::combineReduce
 (
     const List<UPstream::commsStruct>& comms,
     T& value,
@@ -276,7 +282,7 @@ void Foam::Pstream::combineAllGather
 
 
 template<class T, class CombineOp>
-void Foam::Pstream::combineAllGather
+void Foam::Pstream::combineReduce
 (
     T& value,
     const CombineOp& cop,
@@ -526,22 +532,7 @@ void Foam::Pstream::listCombineScatter
 
 
 template<class T, class CombineOp>
-void Foam::Pstream::listCombineAllGather
+void Foam::Pstream::listCombineReduce
-(
-    const List<UPstream::commsStruct>& comms,
-    List<T>& values,
-    const CombineOp& cop,
-    const int tag,
-    const label comm
-)
-{
-    Pstream::listCombineGather(comms, values, cop, tag, comm);
-    Pstream::broadcast(values, comm);
-}
-
-
-template<class T, class CombineOp>
-void Foam::Pstream::listCombineAllGather
 (
     List<T>& values,
     const CombineOp& cop,
@@ -747,22 +738,7 @@ void Foam::Pstream::mapCombineScatter
 
 
 template<class Container, class CombineOp>
-void Foam::Pstream::mapCombineAllGather
+void Foam::Pstream::mapCombineReduce
-(
-    const List<UPstream::commsStruct>& comms,
-    Container& values,
-    const CombineOp& cop,
-    const int tag,
-    const label comm
-)
-{
-    Pstream::mapCombineGather(comms, values, cop, tag, comm);
-    Pstream::broadcast(values, comm);
-}
-
-
-template<class Container, class CombineOp>
-void Foam::Pstream::mapCombineAllGather
 (
     Container& values,
     const CombineOp& cop,

src/OpenFOAM/db/IOstreams/Pstreams/PstreamCombineReduceOps.H

@@ -9,34 +9,16 @@
     Copyright (C) 2022 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
-    This file is part of OpenFOAM.
+    This file is part of OpenFOAM, distributed under GPL-3.0-or-later.
-
-    OpenFOAM is free software: you can redistribute it and/or modify it
-    under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
-    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
-    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
-    for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
-
-InClass
-    Foam
 
 Description
-    Combination-Reduction operation for a parallel run.  The
+    Compatibility include (AUG-2022).
-    information from all nodes is collected on the master node,
+    Foam::combineReduce wrapper for Pstream::combineReduce
-    combined using the given combination function and the result is
-    broadcast to all nodes
 
 \*---------------------------------------------------------------------------*/
 
-#ifndef Foam_PstreamCombineReduceOps_H
+#ifndef FoamCompat_PstreamCombineReduceOps_H
-#define Foam_PstreamCombineReduceOps_H
+#define FoamCompat_PstreamCombineReduceOps_H
 
 #include "Pstream.H"
 #include "ops.H"
@@ -48,20 +30,7 @@ namespace Foam
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
-template<class T, class CombineOp>
+//- Compatibility wrapper for Pstream::combineReduce
-void combineReduce
-(
-    const List<UPstream::commsStruct>& comms,
-    T& value,
-    const CombineOp& cop,
-    const int tag,
-    const label comm
-)
-{
-    Pstream::combineAllGather(comms, value, cop, tag, comm);
-}
-
-
 template<class T, class CombineOp>
 void combineReduce
 (
@@ -71,7 +40,7 @@ void combineReduce
     const label comm = UPstream::worldComm
 )
 {
-    Pstream::combineAllGather(value, cop, tag, comm);
+    Pstream::combineReduce(value, cop, tag, comm);
 }
 
 

src/OpenFOAM/db/IOstreams/Pstreams/PstreamGatherList.C

@@ -253,7 +253,7 @@ void Foam::Pstream::scatterList
                 {
                     fromAbove >> values[leafID];
 
-                    if (debug)
+                    if (debug & 2)
                     {
                         Pout<< " received through "
                             << myComm.above() << " data for:" << leafID
@@ -304,7 +304,7 @@ void Foam::Pstream::scatterList
                 {
                     toBelow << values[leafID];
 
-                    if (debug)
+                    if (debug & 2)
                     {
                         Pout<< " sent through "
                             << belowID << " data for:" << leafID
@@ -341,20 +341,6 @@ void Foam::Pstream::scatterList
 }
 
 
-template<class T>
-void Foam::Pstream::allGatherList
-(
-    const List<UPstream::commsStruct>& comms,
-    List<T>& values,
-    const int tag,
-    const label comm
-)
-{
-    Pstream::gatherList(comms, values, tag, comm);
-    Pstream::scatterList(comms, values, tag, comm);
-}
-
-
 template<class T>
 void Foam::Pstream::allGatherList
 (

src/OpenFOAM/db/IOstreams/Pstreams/PstreamReduceOps.H

@@ -35,8 +35,9 @@ Description
 #ifndef Foam_PstreamReduceOps_H
 #define Foam_PstreamReduceOps_H
 
-#include "ops.H"
+#include "Pstream.H"
 #include "FixedList.H"
+#include "ops.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //