Do not allow for implicit casts from Tensor to Point.

These are likely invalid uses of class Point and should use Tensor instead.
At the same time, still allow for explicit casts.

diff --git a/doc/news/changes.h b/doc/news/changes.h
index 2106353a8eae80729eee7d834b319d0cef191c8a..39e06367169af47bd0f56cb554cfcfc347182457 100644 (file)
--- a/doc/news/changes.h
+++ b/doc/news/changes.h
@@ -38,6 +38,19 @@ inconvenience this causes.
 </p>
 
 <ol>
+  <li> Changed: Implicit conversion from Tensor@<1,dim@> to Point@<dim@> was
+  previously possible. This has now been prohibited (but you can still
+  do the conversion with an explicit cast) as such conversions are
+  likely incorrect uses of class Point (which should represent only
+  points in space, i.e., vectors anchored at the origin) whereas Tensor
+  should be used for vectors anchored elsewhere (such as normal vectors,
+  directions, differences between points, etc). The difference in
+  usage between Point and Tensor have now been clarified in the documentation
+  of class Point.
+  <br>
+  (Wolfgang Bangerth, 2015/01/12)
+  </li>
+
   <li> Changed: The project configuration no longer exports
   <code>[...]/include/deal.II</code>. Thus it is now mandatory to prefix
   all includes of deal.II headers with <code>deal.II/</code>, i.e.

diff --git a/include/deal.II/base/point.h b/include/deal.II/base/point.h
index 75a10626739faf28bb11d499defccda6a885cb52..ebb244e8195ff0cf17e61414e0e96837e5d908c7 100644 (file)
--- a/include/deal.II/base/point.h
+++ b/include/deal.II/base/point.h
@@ -90,7 +90,7 @@ public:
   /**
    * Convert a tensor to a point.
    */
-  Point (const Tensor<1,dim,Number> &);
+  explicit Point (const Tensor<1,dim,Number> &);
 
   /**
    * Constructor for one dimensional points. This function is only implemented
@@ -324,7 +324,9 @@ inline
 Point<dim,Number>
 Point<dim,Number>::operator + (const Tensor<1,dim,Number> &p) const
 {
-  return (Point<dim,Number>(*this) += p);
+  Point<dim,Number> tmp = *this;
+  tmp += p;
+  return tmp;
 }
 
 
@@ -344,7 +346,9 @@ inline
 Point<dim,Number>
 Point<dim,Number>::operator - (const Tensor<1,dim,Number> &p) const
 {
-  return (Point<dim,Number>(*this) -= p);
+  Point<dim,Number> tmp = *this;
+  tmp -= p;
+  return tmp;
 }
 
 
@@ -367,7 +371,9 @@ inline
 Point<dim,Number>
 Point<dim,Number>::operator * (const Number factor) const
 {
-  return (Point<dim,Number>(*this) *= factor);
+  Point<dim,Number> tmp = *this;
+  tmp *= factor;
+  return tmp;
 }
 
 
@@ -416,7 +422,9 @@ template <int dim, typename Number>
 inline
 Point<dim,Number> Point<dim,Number>::operator / (const Number factor) const
 {
-  return (Point<dim,Number>(*this) /= factor);
+  Point<dim,Number> tmp = *this;
+  tmp /= factor;
+  return tmp;
 }