From: Martin Kronbichler <kronbichler@lnm.mw.tum.de>
Date: Sat, 11 Jun 2016 20:23:41 +0000 (+0200)
Subject: Also allow MPI::sum on complex numbers
X-Git-Tag: v8.5.0-rc1~977^2~6
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=418920b2e27d53d4c24351fff3d7a4ae07c32c21;p=dealii.git

Also allow MPI::sum on complex numbers
---

diff --git a/include/deal.II/base/mpi.templates.h b/include/deal.II/base/mpi.templates.h
index f4108f2142..a5806cc217 100644
--- a/include/deal.II/base/mpi.templates.h
+++ b/include/deal.II/base/mpi.templates.h
@@ -121,6 +121,43 @@ namespace Utilities
           }
       }
 
+      template <typename T>
+      void all_reduce (const MPI_Op                   &mpi_op,
+                       const std::complex<T> *const    values,
+                       const MPI_Comm                 &mpi_communicator,
+                       std::complex<T>                *output,
+                       const std::size_t               size)
+      {
+#ifdef DEAL_II_WITH_MPI
+        if (job_supports_mpi())
+          {
+            T dummy_selector;
+            MPI_Allreduce (values != output
+                           ?
+                           // TODO This const_cast is only needed for older
+                           // (e.g., openMPI 1.6, released in 2012)
+                           // implementations of MPI-2. It is not needed as of
+                           // MPI-3 and we should remove it at some point in
+                           // the future.
+                           const_cast<void *>(static_cast<const void *>(values))
+                           :
+                           MPI_IN_PLACE,
+                           static_cast<void *>(output),
+                           static_cast<int>(size*2),
+                           internal::mpi_type_id(&dummy_selector),
+                           mpi_op,
+                           mpi_communicator);
+          }
+        else
+#endif
+          {
+            (void)mpi_op;
+            (void)mpi_communicator;
+            for (std::size_t i=0; i<size; ++i)
+              output[i] = values[i];
+          }
+      }
+
       template <typename T>
       T all_reduce (const MPI_Op &mpi_op,
                     const T &t,
diff --git a/source/base/mpi.inst.in b/source/base/mpi.inst.in
index 531f86beb1..19a06a0328 100644
--- a/source/base/mpi.inst.in
+++ b/source/base/mpi.inst.in
@@ -39,6 +39,19 @@ for (S : MPI_SCALARS)
 }
 
 
+for (S : COMPLEX_SCALARS)
+{
+  template
+  void sum<S> (const Vector<S> &, const MPI_Comm &, Vector<S> &);
+
+  template
+  S sum<S> (const S &, const MPI_Comm &);
+
+  template
+  void sum<S> (const std::vector<S> &, const MPI_Comm &, std::vector<S> &);
+}
+
+
 for (S : REAL_SCALARS; rank: RANKS; dim : SPACE_DIMENSIONS)
 {
   template