Add small test for Matrix::setIdentity()

This is to exhibit the bug that makes the jacobisvd_7 test fail.

test/CMakeLists.txt

@@ -161,6 +161,7 @@ ei_add_test(swap)
 ei_add_test(conservative_resize)
 ei_add_test(permutationmatrices)
 ei_add_test(eigen2support)
+ei_add_test(nullary)
 
 ei_add_test(prec_inverse_4x4)
 

test/nullary.cpp

@@ -0,0 +1,67 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// Copyright (C) 2010 Jitse Niesen <jitse@maths.leeds.ac.uk>
+//
+// 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"
+#include <Eigen/Array>
+
+template<typename MatrixType>
+bool equalsIdentity(const MatrixType& A)
+{
+  typedef typename MatrixType::Scalar Scalar;
+  Scalar zero = static_cast<Scalar>(0);
+
+  bool offDiagOK = true;
+  for (int i = 0; i < A.rows(); ++i) {
+    for (int j = i+1; j < A.cols(); ++j) {
+      offDiagOK = offDiagOK && (A(i,j) == zero);
+    }
+  }
+  for (int i = 0; i < A.rows(); ++i) {
+    for (int j = 0; j < i; ++j) {
+      offDiagOK = offDiagOK && (A(i,j) == zero);
+    }
+  }
+
+  bool diagOK = (A.diagonal().array() == 1).all();
+  return offDiagOK && diagOK;
+}
+
+template<typename MatrixType>
+void testMatrixType(const MatrixType& m)
+{
+  const int rows = m.rows();
+  const int cols = m.cols();
+
+  MatrixType A;
+  A.setIdentity(rows, cols);
+  VERIFY(equalsIdentity(A));
+  VERIFY(equalsIdentity(MatrixType::Identity(rows, cols)));
+}
+
+void test_nullary()
+{
+  CALL_SUBTEST_1( testMatrixType(Matrix2d()) );
+  CALL_SUBTEST_2( testMatrixType(MatrixXcf(50,50)) );
+  CALL_SUBTEST_3( testMatrixType(MatrixXf(5,7)) );
+}