From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Fri, 27 Apr 2018 19:39:12 +0000 (-0600)
Subject: Make FiniteElement::operator== virtual.
X-Git-Tag: v9.0.0-rc1~30^2~2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=392f0a6b0363215844788c143c3363cb73e0579b;p=dealii.git

Make FiniteElement::operator== virtual.

Also provide a bit more documentation about what it does.
---

diff --git a/include/deal.II/fe/fe.h b/include/deal.II/fe/fe.h
index fac7ca852b..273be3c05e 100644
--- a/include/deal.II/fe/fe.h
+++ b/include/deal.II/fe/fe.h
@@ -1333,13 +1333,18 @@ public:
   //@}
 
   /**
-   * Comparison operator. We also check for equality of the name returned by
-   * get_name() and for equality of the constraint matrix, which is quite an
-   * expensive operation.  Do therefore use this function with care, if
-   * possible only for debugging purposes.
+   * Comparison operator.
+   *
+   * The implementation in the current class checks for equality of the name
+   * returned by get_name() and for equality of the constraint matrix, as well
+   * as all of the fields in FiniteElementData. This covers most cases where
+   * elements can differ, but there are cases of derived elements that are
+   * different and for which the current function still returns @p true.
+   * For these cases, derived classes should overload this function.
    *
    * We do not compare the matrix arrays #restriction and #prolongation.
    */
+  virtual
   bool operator == (const FiniteElement<dim,spacedim> &) const;
 
   /**