From c1fee1ab8859455b4c6475756967fe8bcc7a4b32 Mon Sep 17 00:00:00 2001
From: Yong-Dian Jian <ydjian@gmail.com>
Date: Sat, 25 Sep 2010 13:46:16 +0000
Subject: [PATCH] in spqr_householder, use heap when the expected array size is
 greater than 2M bytes, otherwise, use local stack. Could have a better fix
 globally

---
 base/SPQRUtil.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/base/SPQRUtil.cpp b/base/SPQRUtil.cpp
index 52180afc6..3552009ce 100644
--- a/base/SPQRUtil.cpp
+++ b/base/SPQRUtil.cpp
@@ -94,8 +94,17 @@ namespace gtsam {
 				Stair[j] = m;
 		}
 
+
+		// YDJ: allocate buffer if m*n grows more than 2M bytes
+		const int sz = 250000; // the stack is limited to 2M, o
+		const int mn = m*n ;
+		double buf[sz] ;
+		double *a ;
+		if ( mn > sz ) a = new double [mn] ;
+		else a = buf ;
+
 		// convert from row major to column major
-		double a[m*n]; int k = 0;
+		int k = 0;
 		for(int j=0; j<n; j++)
 			for(int i=0; i<m; i++, k++)
 				a[k] = A(i,j);
@@ -126,6 +135,8 @@ namespace gtsam {
 				A(i,j) = a[k];
 		}
 
+		if ( mn > sz ) delete [] a;
+
 		delete []Stair;
 		cholmod_l_finish(&cc);
 	}