From cac147ba10dc82927c95c9c70bb35a4afa66ac45 Mon Sep 17 00:00:00 2001
From: Gael Guennebaud <g.gael@free.fr>
Date: Mon, 19 Jul 2010 10:45:06 +0200
Subject: [PATCH] add support for determinant on empty matrix

---
 Eigen/src/LU/Determinant.h | 2 ++
 test/determinant.cpp       | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/Eigen/src/LU/Determinant.h b/Eigen/src/LU/Determinant.h
index d0b70a31c..ea7db9c0f 100644
--- a/Eigen/src/LU/Determinant.h
+++ b/Eigen/src/LU/Determinant.h
@@ -47,6 +47,8 @@ template<typename Derived,
 {
   static inline typename ei_traits<Derived>::Scalar run(const Derived& m)
   {
+    if(Derived::ColsAtCompileTime==Dynamic && m.rows()==0)
+      return typename ei_traits<Derived>::Scalar(1);
     return m.partialPivLu().determinant();
   }
 };
diff --git a/test/determinant.cpp b/test/determinant.cpp
index 494fa5eab..8112131b7 100644
--- a/test/determinant.cpp
+++ b/test/determinant.cpp
@@ -61,6 +61,9 @@ template<typename MatrixType> void determinant(const MatrixType& m)
   m2 = m1;
   m2.row(i) *= x;
   VERIFY_IS_APPROX(m2.determinant(), m1.determinant() * x);
+  
+  // check empty matrix
+  VERIFY_IS_APPROX(m2.block(0,0,0,0).determinant(), Scalar(1));
 }
 
 void test_determinant()