Bugfix:

In operator= for assigning a BCRSMatrix that was constructed without
specifying the number of nonzero one has to calculate the number of
nonzeros before allocating memory.

[[Imported from SVN: r699]]

istl/bcrsmatrix.hh

@@ -427,8 +427,15 @@ namespace Dune {
         // free rows
         A::template free<row_type>(r);
 
+      if (Mat.nnz<=0)
+      {
+        nnz = 0;
+        for (size_type i=0; i<Mat.n; i++)
+          nnz += Mat.r[i].getsize();
+      }
+
       // allocate a,j
-      allocate(Mat.n, Mat.m, Mat.nnz, n!=Mat.n);
+      allocate(Mat.n, Mat.m, nnz, n!=Mat.n);
 
       // build window structure
       copyWindowStructure(Mat);