From: Daniel Arndt <daniel.arndt@iwr.uni-heidelberg.de>
Date: Wed, 22 Mar 2017 18:11:52 +0000 (+0100)
Subject: Check access in SparsityPatter::compress()
X-Git-Tag: v8.5.0-rc1~19^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F4095%2Fhead;p=dealii.git

Check access in SparsityPatter::compress()
---

diff --git a/source/lac/sparsity_pattern.cc b/source/lac/sparsity_pattern.cc
index fdd32cfbc2..e249977736 100644
--- a/source/lac/sparsity_pattern.cc
+++ b/source/lac/sparsity_pattern.cc
@@ -437,8 +437,11 @@ SparsityPattern::compress ()
       // some internal checks: either the matrix is not quadratic, or if it
       // is, then the first element of this row must be the diagonal element
       // (i.e. with column index==line number)
+      // this test only makes sense if we have written to the index
+      // rowstart_line in new_colnums which is the case if row_length is not 0,
+      // so check this first
       Assert ((!store_diagonal_first_in_row) ||
-              (new_colnums[rowstart[line]] == line),
+              (row_length != 0 && new_colnums[rowstart[line]] == line),
               ExcInternalError());
       // assert that the first entry does not show up in the remaining ones
       // and that the remaining ones are unique among themselves (this handles