From b66516e746f9d470b547f47e23a96329ff6ce73c Mon Sep 17 00:00:00 2001
From: Benoit Jacob <jacob.benoit.1@gmail.com>
Date: Sat, 19 Sep 2009 20:00:36 -0400
Subject: [PATCH] fix bug #42: add missing Transform::Identity()

---
 Eigen/src/Geometry/Transform.h | 4 ++++
 test/geometry.cpp              | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/Eigen/src/Geometry/Transform.h b/Eigen/src/Geometry/Transform.h
index 76f47a66f..8425a1cd9 100644
--- a/Eigen/src/Geometry/Transform.h
+++ b/Eigen/src/Geometry/Transform.h
@@ -198,6 +198,10 @@ public:
 
   /** \sa MatrixBase::setIdentity() */
   void setIdentity() { m_matrix.setIdentity(); }
+  static const typename MatrixType::IdentityReturnType Identity()
+  {
+    return MatrixType::Identity();
+  }
 
   template<typename OtherDerived>
   inline Transform& scale(const MatrixBase<OtherDerived> &other);
diff --git a/test/geometry.cpp b/test/geometry.cpp
index c76054322..d0e69439b 100644
--- a/test/geometry.cpp
+++ b/test/geometry.cpp
@@ -151,7 +151,13 @@ template<typename Scalar> void geometry(void)
     a = ei_random<Scalar>(-Scalar(0.4)*Scalar(M_PI), Scalar(0.4)*Scalar(M_PI));
   q1 = AngleAxisx(a, v0.normalized());
   Transform3 t0, t1, t2;
+  // first test setIdentity() and Identity()
   t0.setIdentity();
+  VERIFY_IS_APPROX(t0.matrix(), Transform3::MatrixType::Identity());
+  t0.matrix().setZero();
+  t0 = Transform3::Identity();
+  VERIFY_IS_APPROX(t0.matrix(), Transform3::MatrixType::Identity());
+
   t0.linear() = q1.toRotationMatrix();
   t1.setIdentity();
   t1.linear() = q1.toRotationMatrix();