From da77fad749054f28b725d934fb79151063b2e0de Mon Sep 17 00:00:00 2001
From: Holger Vogt <holger.vogt@uni-due.de>
Date: Wed, 22 Feb 2023 15:31:47 +0100
Subject: [PATCH] In the very rare case of pPivot being NULL, prevent a crsh by
 reordering the matrix.

---
 src/maths/sparse/spfactor.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/maths/sparse/spfactor.c b/src/maths/sparse/spfactor.c
index 337ad2ace..de5de6177 100644
--- a/src/maths/sparse/spfactor.c
+++ b/src/maths/sparse/spfactor.c
@@ -228,6 +228,11 @@ spOrderAndFactor(MatrixPtr Matrix, RealNumber RHS[], RealNumber RelThreshold,
             INCRESP;
 #endif
             pPivot = Matrix->Diag[Step];
+            if (!pPivot) {
+                fprintf(stderr, "Warning: spfactor.c, 230, Pivot for step = %d not found\n", Step);
+                ReorderingRequired = YES;
+                break; /* for loop */
+            }
             LargestInCol = FindLargestInCol(pPivot->NextInCol);
             if ((LargestInCol * RelThreshold < ELEMENT_MAG(pPivot))) {
                 if (Matrix->Complex)