From 2d9afc3909569455bfc23375404f927784766bb6 Mon Sep 17 00:00:00 2001
From: Doug Torrance <dtorrance@piedmont.edu>
Date: Wed, 15 May 2024 14:07:53 -0400
Subject: [PATCH] Don't call LAPACK when LU-decomposing empty real/complex
 matrices

Otherwise, Macaulay2 crashes

Fixes bug reported by Joel Louwsma in Zulip
---
 M2/Macaulay2/e/dmat-lu-inplace.hpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/M2/Macaulay2/e/dmat-lu-inplace.hpp b/M2/Macaulay2/e/dmat-lu-inplace.hpp
index 0d2905beefc..1e9f2ef1f6f 100644
--- a/M2/Macaulay2/e/dmat-lu-inplace.hpp
+++ b/M2/Macaulay2/e/dmat-lu-inplace.hpp
@@ -284,6 +284,9 @@ inline void DMatLUinPlace<M2::ARingRR>::computeLU()
   int info;
   int min = (rows <= cols) ? rows : cols;
 
+  if (min == 0)
+    return;
+
   // printf("entering DMatLUinPlace::computeLUNaive for RR\n");
 
   int* perm = newarray_atomic(int, min);
@@ -345,6 +348,9 @@ inline void DMatLUinPlace<M2::ARingCC>::computeLU()
   int info;
   int min = (rows <= cols) ? rows : cols;
 
+  if (min == 0)
+    return;
+
   // printf("entering DMatLUtemplate::computeLUNaive for RR\n");
 
   int* perm = newarray_atomic(int, min);