From dc7e4e3e2508e3c66bec565a5391f01753938516 Mon Sep 17 00:00:00 2001
From: Denis Davydov <davydden@gmail.com>
Date: Tue, 16 Jun 2015 23:01:54 +0200
Subject: [PATCH] extend operator= for PETSc MPI vector to handle
 complex-valued case

---
 .../deal.II/lac/parallel_vector.templates.h   | 29 ++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/include/deal.II/lac/parallel_vector.templates.h b/include/deal.II/lac/parallel_vector.templates.h
index 5e7ab011a9..0230a8e926 100644
--- a/include/deal.II/lac/parallel_vector.templates.h
+++ b/include/deal.II/lac/parallel_vector.templates.h
@@ -210,6 +210,33 @@ namespace parallel
 
 #ifdef DEAL_II_WITH_PETSC
 
+    namespace internal
+    {
+      template <typename PETSC_Number, typename Number>
+      void copy_petsc_vector (const PETSC_Number *petsc_start_ptr,
+                              const PETSC_Number *petsc_end_ptr,
+                              Number *ptr)
+      {
+        std::copy(petsc_start_ptr, petsc_end_ptr, ptr);
+      }
+
+      template <typename PETSC_Number, typename Number>
+      void copy_petsc_vector (const std::complex<PETSC_Number> *petsc_start_ptr,
+                              const std::complex<PETSC_Number> *petsc_end_ptr,
+                              std::complex<Number> *ptr)
+      {
+        std::copy(petsc_start_ptr, petsc_end_ptr, ptr);
+      }
+
+      template <typename PETSC_Number, typename Number>
+      void copy_petsc_vector (const std::complex<PETSC_Number> *petsc_start_ptr,
+                              const std::complex<PETSC_Number> *petsc_end_ptr,
+                              Number *ptr)
+      {
+        AssertThrow(false, ExcMessage("Tried to copy complex -> real"));
+      }
+    }
+
     template <typename Number>
     Vector<Number> &
     Vector<Number>::operator = (const PETScWrappers::MPI::Vector &petsc_vec)
@@ -223,7 +250,7 @@ namespace parallel
       AssertThrow (ierr == 0, ExcPETScError(ierr));
 
       const size_type vec_size = local_size();
-      std::copy (start_ptr, start_ptr + vec_size, begin());
+      internal::copy_petsc_vector (start_ptr, start_ptr + vec_size, begin());
 
       // restore the representation of the vector
       ierr = VecRestoreArray (static_cast<const Vec &>(petsc_vec), &start_ptr);
-- 
2.39.5