allow contraction of tensors of different base type

diff --git a/include/deal.II/base/tensor.h b/include/deal.II/base/tensor.h
index cabc4643fe3d0bb9f47ce8875dd68090259d0a99..c0a24c90990d7a26ecb3917ed799a0e3ade2d45d 100644 (file)
--- a/include/deal.II/base/tensor.h
+++ b/include/deal.II/base/tensor.h
@@ -761,12 +761,13 @@ std::ostream &operator << (std::ostream &out, const Tensor<rank_,1> &p)
  * @relates Tensor
  * @author Guido Kanschat, 2000
  */
-template <int dim, typename Number>
+template <int dim, typename Number, typename OtherNumber>
 inline
-Number contract (const Tensor<1,dim,Number> &src1,
-                 const Tensor<1,dim,Number> &src2)
+typename ProductType<Number,OtherNumber>::type
+contract (const Tensor<1,dim,Number> &src1,
+          const Tensor<1,dim,OtherNumber> &src2)
 {
-  Number res = 0.;
+  typename ProductType<Number,OtherNumber>::type res = typename ProductType<Number,OtherNumber>::type();
   for (unsigned int i=0; i<dim; ++i)
     res += src1[i] * src2[i];
 
@@ -789,11 +790,11 @@ Number contract (const Tensor<1,dim,Number> &src1,
  * @relates Tensor
  * @author Wolfgang Bangerth, 2005
  */
-template <int dim, typename Number>
+template <int dim, typename Number, typename OtherNumber>
 inline
-Number
+typename ProductType<Number,OtherNumber>::type
 operator * (const Tensor<1,dim,Number> &src1,
-            const Tensor<1,dim,Number> &src2)
+            const Tensor<1,dim,OtherNumber> &src2)
 {
   return contract(src1, src2);
 }