[goffice] matrix inversion: fix crash.

[Morten Welinder <mortenw src gnome org>]

commit 32dfbbd2c0a582065e753d07fc0ba54a35812e30
Author: Morten Welinder <terra gnome org>
Date:   Mon May 3 09:47:08 2010 -0400

    matrix inversion: fix crash.

 ChangeLog                    |    4 ++++
 NEWS                         |    1 +
 goffice/math/go-regression.c |    3 +++
 3 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 6b0c848..6597160 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2010-05-03  Morten Welinder  <terra gnome org>
+
+	* goffice/math/go-regression.c (LUPDecomp): Handle nan entries.
+
 2010-05-01  Jean Brefort  <jean brefort normalesup org>
 
 	* goffice/canvas/goc-graph.c (goc_graph_do_tooltip): use markup for tips.
diff --git a/NEWS b/NEWS
index 1c0858e..db104a9 100644
--- a/NEWS
+++ b/NEWS
@@ -7,6 +7,7 @@ Jean:
 
 Morten:
 	* Fix week numbers issue.
+	* Fix matrix inversion crash.  [Part of #617469]
 
 --------------------------------------------------------------------------
 goffice 0.8.2:
diff --git a/goffice/math/go-regression.c b/goffice/math/go-regression.c
index 538f78c..c6c56b1 100644
--- a/goffice/math/go-regression.c
+++ b/goffice/math/go-regression.c
@@ -219,6 +219,9 @@ SUFFIX(LUPDecomp) (DOUBLE **A, DOUBLE **LU, int *P, int n, DOUBLE *b_scaled,
 		if (max < lowest)
 			lowest = max;
 
+		if (mov == -1)
+			return GO_REG_invalid_data;
+
 		if (i != mov) {
 			/*swap the two rows */