Implement ConstantTensorFunction<rank,dim> and ZeroTensorFunction<rank,dim>

git-svn-id: https://svn.dealii.org/trunk@29840 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/doc/news/changes.h b/deal.II/doc/news/changes.h
index 738d2bf8708aad5759fdfea270498bf4af20c748..621adb69620ba1ab2caa2a020fe8f986aaa59aa9 100644 (file)
--- a/deal.II/doc/news/changes.h
+++ b/deal.II/doc/news/changes.h
@@ -146,6 +146,13 @@ this function.
 <h3>Specific improvements</h3>
 
 <ol>
+
+<li> New: added ConstantTensorFunction<rank, dim> and ZeroTensorFunction<rank, dim> to provide
+a tensor valued analogue to ConstantFunction and ZeroFunction.
+<br>
+(Matthias Maier, 2013/06/20)
+</li>
+
 <li> Fixed: BlockSparsityPattern::column_number was returning
 wrong values.
 <br>

diff --git a/deal.II/include/deal.II/base/tensor_function.h b/deal.II/include/deal.II/base/tensor_function.h
index b8a7bd791074dd7311361bf05c307731c92e207c..a55fd65326761eae048974d35011602a9fcc2596 100644 (file)
--- a/deal.II/include/deal.II/base/tensor_function.h
+++ b/deal.II/include/deal.II/base/tensor_function.h
@@ -53,66 +53,51 @@ DEAL_II_NAMESPACE_OPEN
  */
 template <int rank, int dim>
 class TensorFunction : public FunctionTime,
-  public Subscriptor
+                       public Subscriptor
 {
 public:
   /**
-   * Define typedefs for the return
-   * types of the <tt>value</tt>
-   * functions.
+   * Define typedefs for the return types of the <tt>value</tt> functions.
    */
   typedef Tensor<rank,dim> value_type;
 
   typedef Tensor<rank+1,dim> gradient_type;
 
   /**
-   * Constructor. May take an
-   * initial value for the time
-   * variable, which defaults to
-   * zero.
+   * Constructor. May take an initial value for the time variable, which
+   * defaults to zero.
    */
   TensorFunction (const double initial_time = 0.0);
 
   /**
-   * Virtual destructor; absolutely
-   * necessary in this case, as
-   * classes are usually not used
-   * by their true type, but rather
-   * through pointers to this base
-   * class.
+   * Virtual destructor; absolutely necessary in this case, as classes are
+   * usually not used by their true type, but rather through pointers to
+   * this base class.
    */
   virtual ~TensorFunction ();
 
   /**
-   * Return the value of the function
-   * at the given point.
+   * Return the value of the function at the given point.
    */
   virtual value_type value (const Point<dim> &p) const;
 
   /**
-   * Set <tt>values</tt> to the point
-   * values of the function at the
-   * <tt>points</tt>.  It is assumed
-   * that <tt>values</tt> already has
-   * the right size, i.e.  the same
-   * size as the <tt>points</tt> array.
+   * Set <tt>values</tt> to the point values of the function at the
+   * <tt>points</tt>.  It is assumed that <tt>values</tt> already has the
+   * right size, i.e.  the same size as the <tt>points</tt> array.
    */
   virtual void value_list (const std::vector<Point<dim> > &points,
                            std::vector<value_type> &values) const;
 
   /**
-   * Return the gradient of the
-   * function at the given point.
+   * Return the gradient of the function at the given point.
    */
   virtual gradient_type gradient (const Point<dim> &p) const;
 
   /**
-   * Set <tt>gradients</tt> to the
-   * gradients of the function at
-   * the <tt>points</tt>.  It is assumed
-   * that <tt>values</tt> already has
-   * the right size, i.e.  the same
-   * size as the <tt>points</tt> array.
+   * Set <tt>gradients</tt> to the gradients of the function at the
+   * <tt>points</tt>.  It is assumed that <tt>values</tt> already has the
+   * right size, i.e.  the same size as the <tt>points</tt> array.
    */
   virtual void gradient_list (const std::vector<Point<dim> >   &points,
                               std::vector<gradient_type> &gradients) const;
@@ -131,6 +116,89 @@ public:
 
 };
 
+
+
+/*
+ * Provide a tensor valued function which always returns a constant tensor
+ * value. Obviously, all derivates of this function are zero.
+ *
+ * @ingroup functions
+ * @author Matthias Maier, 2013
+ */
+template <int rank, int dim>
+class ConstantTensorFunction : public TensorFunction<rank, dim>
+{
+public:
+  /**
+   * Constructor; takes the constant tensor value as an argument.
+   * The reference value is copied internally.
+   *
+   * An initial value for the time variable may be specified, otherwise it
+   * defaults to zero.
+   */
+  ConstantTensorFunction (const dealii::Tensor<rank, dim> &value,
+                          const double initial_time = 0.0);
+
+  /**
+   * Virtual destructor; absolutely necessary in this case, as classes are
+   * usually not used by their true type, but rather through pointers to
+   * this base class.
+   */
+  virtual ~ConstantTensorFunction ();
+
+  /**
+   * Return the value of the function at the given point.
+   */
+  virtual typename dealii::TensorFunction<rank, dim>::value_type value (const Point<dim> &p) const;
+
+  /**
+   * Set <tt>values</tt> to the point values of the function at the
+   * <tt>points</tt>.  It is assumed that <tt>values</tt> already has the
+   * right size, i.e.  the same size as the <tt>points</tt> array.
+   */
+  virtual void value_list (const std::vector<Point<dim> > &points,
+                           std::vector<typename dealii::TensorFunction<rank, dim>::value_type> &values) const;
+
+  /**
+   * Return the gradient of the function at the given point.
+   */
+  virtual typename dealii::TensorFunction<rank, dim>::gradient_type gradient (const Point<dim> &p) const;
+
+  /**
+   * Set <tt>gradients</tt> to the gradients of the function at the
+   * <tt>points</tt>.  It is assumed that <tt>values</tt> already has the
+   * right size, i.e.  the same size as the <tt>points</tt> array.
+   */
+  virtual void gradient_list (const std::vector<Point<dim> > &points,
+                              std::vector<typename dealii::TensorFunction<rank, dim>::gradient_type> &gradients) const;
+
+private:
+  const dealii::Tensor<rank, dim> _value;
+};
+
+
+
+/*
+ * Provide a tensor valued function which always returns zero.
+ * Obviously, all derivates of this function are zero.
+ *
+ * @ingroup functions
+ * @author Matthias Maier, 2013
+ */
+template <int rank, int dim>
+class ZeroTensorFunction : public ConstantTensorFunction<rank, dim>
+{
+public:
+  /**
+   * Constructor.
+   *
+   * An initial value for the time variable may be specified, otherwise it
+   * defaults to zero.
+   */
+  ZeroTensorFunction (const double initial_time = 0.0);
+};
+
+
 DEAL_II_NAMESPACE_CLOSE
 
 #endif

diff --git a/deal.II/source/base/tensor_function.cc b/deal.II/source/base/tensor_function.cc
index ec2d4a1a378adb19083fb5b54321ba59b8aaa5ce..f903ed382ef1ca5986a528205278328fb04bdddb 100644 (file)
--- a/deal.II/source/base/tensor_function.cc
+++ b/deal.II/source/base/tensor_function.cc
@@ -21,6 +21,7 @@
 DEAL_II_NAMESPACE_OPEN
 
 
+
 //////////////////////////////////////////////////////////////////////
 // TensorFunction
 //////////////////////////////////////////////////////////////////////
@@ -82,6 +83,90 @@ TensorFunction<rank, dim>::gradient_list (const std::vector<Point<dim> >   &poin
 }
 
 
+
+//////////////////////////////////////////////////////////////////////
+// ConstantTensorFunction
+//////////////////////////////////////////////////////////////////////
+
+
+template <int rank, int dim>
+ConstantTensorFunction<rank, dim>::ConstantTensorFunction (const Tensor<rank, dim> &value,
+                                                           const double initial_time)
+  :
+  TensorFunction<rank, dim> (initial_time),
+  _value(value)
+{}
+
+
+template <int rank, int dim>
+ConstantTensorFunction<rank, dim>::~ConstantTensorFunction ()
+{}
+
+
+template <int rank, int dim>
+typename TensorFunction<rank, dim>::value_type
+ConstantTensorFunction<rank, dim>::value (const Point<dim> &/*point*/) const
+{
+  return _value;
+}
+
+
+template <int rank, int dim>
+void
+ConstantTensorFunction<rank, dim>::value_list (const std::vector<Point<dim> > &points,
+                                               std::vector<typename TensorFunction<rank, dim>::value_type> &values) const
+{
+  Assert (values.size() == points.size(),
+          ExcDimensionMismatch(values.size(), points.size()));
+
+  for (unsigned int i=0; i<values.size(); ++i)
+    values[i]  = _value;
+}
+
+
+template <int rank, int dim>
+typename TensorFunction<rank, dim>::gradient_type
+ConstantTensorFunction<rank, dim>::gradient (const Point<dim> &) const
+{
+  static const Tensor<rank+1,dim> zero;
+
+  return zero;
+}
+
+
+template <int rank, int dim>
+void
+ConstantTensorFunction<rank, dim>::gradient_list (const std::vector<Point<dim> >   &points,
+                                                  std::vector<typename TensorFunction<rank, dim>::gradient_type> &gradients) const
+{
+  Assert (gradients.size() == points.size(),
+          ExcDimensionMismatch(gradients.size(), points.size()));
+
+  static const Tensor<rank+1,dim> zero;
+
+  for (unsigned int i=0; i<gradients.size(); ++i)
+    gradients[i] = zero;
+}
+
+
+
+//////////////////////////////////////////////////////////////////////
+// ZeroTensorFunction
+//////////////////////////////////////////////////////////////////////
+
+
+template <int rank, int dim>
+ZeroTensorFunction<rank, dim>::ZeroTensorFunction (const double initial_time)
+  :
+  ConstantTensorFunction<rank, dim> (dealii::Tensor<rank, dim>(), initial_time)
+{}
+
+
+
+//////////////////////////////////////////////////////////////////////
+// Explicit instantiations:
+//////////////////////////////////////////////////////////////////////
+
 template class TensorFunction<1,1>;
 template class TensorFunction<2,1>;
 template class TensorFunction<3,1>;
@@ -95,4 +180,31 @@ template class TensorFunction<2,3>;
 template class TensorFunction<3,3>;
 template class TensorFunction<4,3>;
 
+template class ConstantTensorFunction<1,1>;
+template class ConstantTensorFunction<2,1>;
+template class ConstantTensorFunction<3,1>;
+template class ConstantTensorFunction<4,1>;
+template class ConstantTensorFunction<1,2>;
+template class ConstantTensorFunction<2,2>;
+template class ConstantTensorFunction<3,2>;
+template class ConstantTensorFunction<4,2>;
+template class ConstantTensorFunction<1,3>;
+template class ConstantTensorFunction<2,3>;
+template class ConstantTensorFunction<3,3>;
+template class ConstantTensorFunction<4,3>;
+
+template class ZeroTensorFunction<1,1>;
+template class ZeroTensorFunction<2,1>;
+template class ZeroTensorFunction<3,1>;
+template class ZeroTensorFunction<4,1>;
+template class ZeroTensorFunction<1,2>;
+template class ZeroTensorFunction<2,2>;
+template class ZeroTensorFunction<3,2>;
+template class ZeroTensorFunction<4,2>;
+template class ZeroTensorFunction<1,3>;
+template class ZeroTensorFunction<2,3>;
+template class ZeroTensorFunction<3,3>;
+template class ZeroTensorFunction<4,3>;
+
+
 DEAL_II_NAMESPACE_CLOSE