bug #890, add a more general routine to check that two dense object reference to the same data

4 files changed, 45 insertions, 1 deletions

diff --git a/Eigen/src/Core/PermutationMatrix.h b/Eigen/src/Core/PermutationMatrix.h
index 9ec17ca8c..99f5aecdd 100644
--- a/Eigen/src/Core/PermutationMatrix.h
+++ b/Eigen/src/Core/PermutationMatrix.h
@@ -596,7 +596,8 @@ struct permut_matrix_product_retval
       const Index n = Side==OnTheLeft ? rows() : cols();
       // FIXME we need an is_same for expression that is not sensitive to constness. For instance
       // is_same_xpr<Block<const Matrix>, Block<Matrix> >::value should be true.
-      if(is_same<MatrixTypeNestedCleaned,Dest>::value && extract_data(dst) == extract_data(m_matrix))
+      //if(is_same<MatrixTypeNestedCleaned,Dest>::value && extract_data(dst) == extract_data(m_matrix))
+      if(is_same_dense(dst, m_matrix))
       {
         // apply the permutation inplace
         Matrix<bool,PermutationType::RowsAtCompileTime,1,0,PermutationType::MaxRowsAtCompileTime> mask(m_permutation.size());
diff --git a/Eigen/src/Core/util/XprHelper.h b/Eigen/src/Core/util/XprHelper.h
index 562f425bd..55132c8cf 100644
--- a/Eigen/src/Core/util/XprHelper.h
+++ b/Eigen/src/Core/util/XprHelper.h
@@ -606,6 +606,18 @@ template<typename T, int S> struct is_diagonal<DiagonalMatrix<T,S> >
 template<typename S1, typename S2> struct glue_shapes;
 template<> struct glue_shapes<DenseShape,TriangularShape> { typedef TriangularShape type;  };
 
+template<typename T1, typename T2>
+bool is_same_dense(const T1 &mat1, const T2 &mat2, typename enable_if<has_direct_access<T1>::ret&&has_direct_access<T2>::ret, T1>::type * = 0)
+{
+  return (mat1.data()==mat2.data()) && (mat1.innerStride()==mat2.innerStride()) && (mat1.outerStride()==mat2.outerStride());
+}
+
+template<typename T1, typename T2>
+bool is_same_dense(const T1 &, const T2 &, typename enable_if<!(has_direct_access<T1>::ret&&has_direct_access<T2>::ret), T1>::type * = 0)
+{
+  return false;
+}
+
 } // end namespace internal
 
 // we require Lhs and Rhs to have the same scalar type. Currently there is no example of a binary functor
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index ffd905c27..767e82f21 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -181,6 +181,7 @@ ei_add_test(array_for_matrix)
 ei_add_test(array_replicate)
 ei_add_test(array_reverse)
 ei_add_test(ref)
+ei_add_test(is_same_dense)
 ei_add_test(triangular)
 ei_add_test(selfadjoint)
 ei_add_test(product_selfadjoint)
diff --git a/test/is_same_dense.cpp b/test/is_same_dense.cpp
new file mode 100644
index 000000000..318ba8717
--- /dev/null
+++ b/test/is_same_dense.cpp
@@ -0,0 +1,30 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2015 Gael Guennebaud <gael.guennebaud@inria.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#include "main.h"
+
+void test_is_same_dense()
+{
+  MatrixXd m1(10,10);
+  Ref<MatrixXd> ref_m1(m1);
+  Ref<const MatrixXd> const_ref_m1(m1);
+  VERIFY(is_same_dense(m1,m1));
+  VERIFY(is_same_dense(m1,ref_m1));
+  VERIFY(is_same_dense(const_ref_m1,m1));
+  VERIFY(is_same_dense(const_ref_m1,ref_m1));
+  
+  VERIFY(is_same_dense(m1.block(0,0,m1.rows(),m1.cols()),m1));
+  VERIFY(!is_same_dense(m1.row(0),m1.col(0)));
+  
+  Ref<const MatrixXd> const_ref_m1_row(m1.row(1));
+  VERIFY(!is_same_dense(m1.row(1),const_ref_m1_row));
+  
+  Ref<const MatrixXd> const_ref_m1_col(m1.col(1));
+  VERIFY(is_same_dense(m1.col(1),const_ref_m1_col));
+}