Add .resizeLike() method to Matrix.

test/resize.cpp

Index: test/resize.cpp
===================================================================
--- test/resize.cpp	(revision 0)
+++ test/resize.cpp	(revision 0)
@@ -0,0 +1,56 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra. Eigen itself is part of the KDE project.
+//
+// Copyright (C) 2009 Keir Mierle <mierle@gmail.com>
+//
+// Eigen is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// Alternatively, you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of
+// the License, or (at your option) any later version.
+//
+// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License and a copy of the GNU General Public License along with
+// Eigen. If not, see <http://www.gnu.org/licenses/>.
+
+#include "main.h"
+
+template<int rows, int cols>
+void resizeLikeTest()
+{
+  MatrixXf A(rows, cols);
+  MatrixXf B;
+  Matrix<double, rows, cols> C;
+  B.resizeLike(A);
+  C.resizeLike(B);  // Shouldn't crash.
+  VERIFY(B.rows() == rows && B.cols() == cols);
+
+  VectorXf x(rows);
+  RowVectorXf y;
+  y.resizeLike(x);
+  VERIFY(y.rows() == 1 && y.cols() == rows);
+
+  y.resize(cols);
+  x.resizeLike(y);
+  VERIFY(x.rows() == cols && x.cols() == 1);
+}
+
+void resizeLikeTest12() { resizeLikeTest<1,2>(); }
+void resizeLikeTest1020() { resizeLikeTest<10,20>(); }
+void resizeLikeTest31() { resizeLikeTest<3,1>(); }
+
+void test_resize()
+{
+  CALL_SUBTEST( resizeLikeTest12() );
+  CALL_SUBTEST( resizeLikeTest1020() );
+  CALL_SUBTEST( resizeLikeTest31() );
+}