From d337ecccd2ce682e604c2f1a48f53638274f7cec Mon Sep 17 00:00:00 2001
From: kanschat <kanschat@0785d39b-7218-0410-832d-ea1e28bc413d>
Date: Mon, 18 Mar 2013 14:56:11 +0000
Subject: [PATCH] support mixed accuracy preconditioning

git-svn-id: https://svn.dealii.org/trunk@28930 0785d39b-7218-0410-832d-ea1e28bc413d
---
 .../include/deal.II/lac/iterative_inverse.h   | 28 ++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/deal.II/include/deal.II/lac/iterative_inverse.h b/deal.II/include/deal.II/lac/iterative_inverse.h
index 9d0d38e8da..a93dd3369d 100644
--- a/deal.II/include/deal.II/lac/iterative_inverse.h
+++ b/deal.II/include/deal.II/lac/iterative_inverse.h
@@ -77,7 +77,7 @@ public:
   /**
    * Initialization
    * function. Provide a matrix and
-   * preconditioner for th solve in
+   * preconditioner for the solve in
    * vmult().
    */
   template <class MATRIX, class PRECONDITION>
@@ -94,6 +94,14 @@ public:
    */
   void vmult (VECTOR &dst, const VECTOR &src) const;
 
+  /**
+   * Solve for right hand side <tt>src</tt>, but allow for the fact
+   * that the vectors given to this function have different type from
+   * the vectors used by the inner solver.
+   */
+  template <class VECTOR2>
+  void vmult (VECTOR2 &dst, const VECTOR2 &src) const;
+
   /**
    * The solver, which allows
    * selection of the actual solver
@@ -144,10 +152,28 @@ IterativeInverse<VECTOR>::vmult (VECTOR &dst, const VECTOR &src) const
 {
   Assert(matrix.get() != 0, ExcNotInitialized());
   Assert(preconditioner.get() != 0, ExcNotInitialized());
+  dst = 0.;
   solver.solve(*matrix, dst, src, *preconditioner);
 }
 
 
+template <class VECTOR>
+template <class VECTOR2>
+inline void
+IterativeInverse<VECTOR>::vmult (VECTOR2 &dst, const VECTOR2 &src) const
+{
+  Assert(matrix.get() != 0, ExcNotInitialized());
+  Assert(preconditioner.get() != 0, ExcNotInitialized());
+  GrowingVectorMemory<VECTOR> mem;
+  typename VectorMemory<VECTOR>::Pointer sol(mem);
+  typename VectorMemory<VECTOR>::Pointer rhs(mem);
+  sol->reinit(dst);
+  *rhs = src;
+  solver.solve(*matrix, *sol, *rhs, *preconditioner);
+  dst = *sol;
+}
+
+
 
 DEAL_II_NAMESPACE_CLOSE
 
-- 
2.39.5