Update documentation.

This closes #542.

diff --git a/include/deal.II/base/function_time.h b/include/deal.II/base/function_time.h
index 029d2312f0c96552a25275ef97525301cfd52bd2..6e3aa4c459266703d76ccd7ba81d754c5717c388 100644 (file)
--- a/include/deal.II/base/function_time.h
+++ b/include/deal.II/base/function_time.h
@@ -1,6 +1,6 @@
 // ---------------------------------------------------------------------
 //
-// Copyright (C) 1999 - 2014 by the deal.II authors
+// Copyright (C) 1999 - 2015 by the deal.II authors
 //
 // This file is part of the deal.II library.
 //
@@ -42,21 +42,27 @@ DEAL_II_NAMESPACE_OPEN
  * computations which need only be done once for every new time. For example,
  * if a time dependent function had a factor <tt>sin(t)</tt>, then it may be a
  * reasonable choice to calculate this factor in a derived version of
- * <tt>set_time</tt>, store it in a member variable and use that one rather
- * than computing it every time <tt>operator()</tt>, <tt>value_list</tt> or
- * one of the other functions is called.
+ * set_time(), store it in a member variable and use that one rather
+ * than computing it every time <tt>value()</tt>, <tt>value_list</tt> or
+ * one of the other functions of class Function is called.
  *
- * By default, the <tt>advance_time</tt> function calls the <tt>set_time</tt>
+ * By default, the advance_time() function calls the set_time()
  * function with the new time, so it is sufficient in most cases to overload
- * only <tt>set_time</tt> for computations as sketched out above.
+ * only set_time() for computations as sketched out above.
  *
  * The constructor of this class takes an initial value for the time variable,
  * which defaults to zero. Because a default value is given, none of the
  * derived classes needs to take an initial value for the time variable if not
  * needed.
  *
- * Once again the warning: do not use the <tt>time</tt> variable for any other
- * purpose than the intended one! This will inevitably lead to confusion.
+ * @tparam Number The data type in which time values are to be
+ * stored. This will, in almost all cases, simply be the default @p double,
+ * but there are cases where one may want to store the time in a different
+ * (and always scalar) type. An example would be an interval type that can
+ * store a value as well as its uncertainty. Another example
+ * would be a type that allows for Automatic Differentiation (see, for
+ * example, the Sacado type used in step-33) and thereby can generate analytic
+ * (temporal) derivatives of a function.
  *
  *
  * @ingroup functions