From 37fb8e449697de4691321c4d70fae4eabfaf6b4e Mon Sep 17 00:00:00 2001
From: heister <heister@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Thu, 30 May 2013 20:06:25 +0000
Subject: [PATCH] add PETSc matrix copy_from

git-svn-id: https://svn.dealii.org/branches/branch_unify_linear_algebra@29670 0785d39b-7218-0410-832d-ea1e28bc413d
---
 .../include/deal.II/lac/petsc_parallel_sparse_matrix.h |  7 +++++++
 deal.II/source/lac/petsc_parallel_sparse_matrix.cc     | 10 ++++++++++
 2 files changed, 17 insertions(+)

diff --git a/deal.II/include/deal.II/lac/petsc_parallel_sparse_matrix.h b/deal.II/include/deal.II/lac/petsc_parallel_sparse_matrix.h
index 7eb8b9d087..93c04f4371 100644
--- a/deal.II/include/deal.II/lac/petsc_parallel_sparse_matrix.h
+++ b/deal.II/include/deal.II/lac/petsc_parallel_sparse_matrix.h
@@ -294,6 +294,13 @@ namespace PETScWrappers
        */
       SparseMatrix &operator = (const value_type d);
 
+
+      /**
+       * Make a copy of the PETSc matrix @p other. It is assumed that both matrices have
+       * the same SparsityPattern.
+       */
+      void copy_from(const SparseMatrix & other);
+
       /**
        * Throw away the present matrix and
        * generate one that has the same
diff --git a/deal.II/source/lac/petsc_parallel_sparse_matrix.cc b/deal.II/source/lac/petsc_parallel_sparse_matrix.cc
index 405bc0c2bf..ecc5dac544 100644
--- a/deal.II/source/lac/petsc_parallel_sparse_matrix.cc
+++ b/deal.II/source/lac/petsc_parallel_sparse_matrix.cc
@@ -99,7 +99,17 @@ namespace PETScWrappers
       return *this;
     }
 
+    void
+    SparseMatrix::copy_from (const SparseMatrix &other)
+    {
+      if (&other == this)
+        return;
+
+      this->communicator = other.communicator;
 
+      int ierr = MatCopy(other.matrix, matrix, SAME_NONZERO_PATTERN);
+      AssertThrow (ierr == 0, ExcPETScError(ierr));
+    }
 
     void
     SparseMatrix::reinit (const MPI_Comm    &communicator,
-- 
2.39.5