tensor.h: Let the cross_product functions return its result

All other function signatures also return their result - do the same here
and deprecate the old signatures.

diff --git a/include/deal.II/base/tensor.h b/include/deal.II/base/tensor.h
index 1f75f7a7da1c0e7bd3b0cfe31374acde911c0e07..a90dbfd024086018f50cb311e63a4a38d149e829 100644 (file)
--- a/include/deal.II/base/tensor.h
+++ b/include/deal.II/base/tensor.h
@@ -2167,51 +2167,57 @@ Number determinant (const Tensor<1,1,Number> &t)
 
 
 /**
- * Cross-product in 2d. This is just a rotation by 90 degrees clockwise to
- * compute the outer normal from a tangential vector. This function is defined
- * for all space dimensions to allow for dimension independent programming
- * (e.g. within switches over the space dimension), but may only be called if
- * the actual dimension of the arguments is two (e.g. from the <tt>dim==2</tt>
- * case in the switch).
+ * Returns the cross-product in 2d. This is just a rotation by 90 degrees
+ * clockwise to compute the outer normal from a tangential vector. This
+ * function is defined for all space dimensions to allow for dimension
+ * independent programming (e.g. within switches over the space dimension),
+ * but may only be called if the actual dimension of the arguments is two
+ * (e.g. from the <tt>dim==2</tt> case in the switch).
  *
  * @relates Tensor
  * @author Guido Kanschat, 2001
  */
 template <int dim, typename Number>
 inline
-void
-cross_product (Tensor<1,dim,Number>       &dst,
-               const Tensor<1,dim,Number> &src)
+Tensor<1,dim,Number>
+cross_product (const Tensor<1,dim,Number> &src)
 {
   Assert (dim==2, ExcInternalError());
 
-  dst[0] = src[1];
-  dst[1] = -src[0];
+  Tensor<1, dim, Number> result;
+
+  result[0] = src[1];
+  result[1] = -src[0];
+
+  return result;
 }
 
 
 /**
- * Cross-product of 2 vectors in 3d. This function is defined for all space
- * dimensions to allow for dimension independent programming (e.g. within
- * switches over the space dimension), but may only be called if the actual
- * dimension of the arguments is three (e.g. from the <tt>dim==3</tt> case in
- * the switch).
+ * Returns the cross-product of 2 vectors in 3d. This function is defined
+ * for all space dimensions to allow for dimension independent programming
+ * (e.g. within switches over the space dimension), but may only be called
+ * if the actual dimension of the arguments is three (e.g. from the
+ * <tt>dim==3</tt> case in the switch).
  *
  * @relates Tensor
  * @author Guido Kanschat, 2001
  */
 template <int dim, typename Number>
 inline
-void
-cross_product (Tensor<1,dim,Number>       &dst,
-               const Tensor<1,dim,Number> &src1,
+Tensor<1,dim,Number>
+cross_product (const Tensor<1,dim,Number> &src1,
                const Tensor<1,dim,Number> &src2)
 {
   Assert (dim==3, ExcInternalError());
 
-  dst[0] = src1[1]*src2[2] - src1[2]*src2[1];
-  dst[1] = src1[2]*src2[0] - src1[0]*src2[2];
-  dst[2] = src1[0]*src2[1] - src1[1]*src2[0];
+  Tensor<1, dim, Number> result;
+
+  result[0] = src1[1]*src2[2] - src1[2]*src2[1];
+  result[1] = src1[2]*src2[0] - src1[0]*src2[2];
+  result[2] = src1[0]*src2[1] - src1[1]*src2[0];
+
+  return result;
 }
 
 
@@ -2536,4 +2542,7 @@ linfty_norm (const Tensor<2,dim,Number> &t)
 
 DEAL_II_NAMESPACE_CLOSE
 
+// include deprecated non-member functions operating on Tensor
+#include <deal.II/base/tensor_deprecated.h>
+
 #endif

diff --git a/include/deal.II/base/tensor_deprecated.h b/include/deal.II/base/tensor_deprecated.h
new file mode 100644 (file)
index 0000000..9bc6663
--- /dev/null
+++ b/include/deal.II/base/tensor_deprecated.h
@@ -0,0 +1,66 @@
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 1998 - 2015 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// The deal.II library is free software; you can use it, redistribute
+// it, and/or modify it under the terms of the GNU Lesser General
+// Public License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+// The full text of the license can be found in the file LICENSE at
+// the top level of the deal.II distribution.
+//
+// ---------------------------------------------------------------------
+
+#ifndef dealii__tensor_deprecated_h
+#define dealii__tensor_deprecated_h
+
+#include <deal.II/base/tensor.h>
+
+
+/* --------- Deprecated non-member functions operating on tensors. ---------- */
+
+DEAL_II_NAMESPACE_OPEN
+
+//@}
+/**
+ * @name Deprecated Tensor operations
+ */
+//@{
+
+
+/**
+ * The cross-product of 2 vectors in 3d.
+ *
+ * @deprecated Use the cross_product function that returns the value.
+ * @relates Tensor
+ */
+template <int dim, typename Number>
+inline
+void
+cross_product (Tensor<1,dim,Number>       &dst,
+               const Tensor<1,dim,Number> &src1,
+               const Tensor<1,dim,Number> &src2) DEAL_II_DEPRECATED;
+
+
+#ifndef DOXYGEN
+
+
+template <int dim, typename Number>
+inline
+void
+cross_product (Tensor<1,dim,Number>       &dst,
+               const Tensor<1,dim,Number> &src1,
+               const Tensor<1,dim,Number> &src2)
+{
+  dst = cross_product(src1, src2);
+}
+
+#endif /* DOXYGEN */
+
+//@}
+
+DEAL_II_NAMESPACE_CLOSE
+
+#endif