--- /dev/null
+// ---------------------------------------------------------------------
+//
+// Copyright (C) 2015 - 2016 by the deal.II authors
+//
+// This file is part of the deal.II library.
+//
+// The deal.II library is free software; you can use it, 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 2.1 of the License, or (at your option) any later version.
+// The full text of the license can be found in the file LICENSE.md at
+// the top level directory of deal.II.
+//
+// ---------------------------------------------------------------------
+
+// Verify that the inverse_operator function signature without a
+// preconditioner argument and the one with PreconditionIdentity() as a
+// temporary works correctly.
+
+#include <deal.II/lac/linear_operator.h>
+#include <deal.II/lac/packaged_operation.h>
+#include <deal.II/lac/precondition.h>
+#include <deal.II/lac/solver_cg.h>
+#include <deal.II/lac/sparse_matrix.h>
+#include <deal.II/lac/sparsity_pattern.h>
+#include <deal.II/lac/vector.h>
+
+#include "../tests.h"
+
+using namespace dealii;
+
+int
+main()
+{
+ initlog();
+
+ Vector<double> answer(2);
+ answer[0] = 0.25;
+ answer[1] = 0.25;
+
+ SparsityPattern sparsity_pattern(2, 2, 1);
+ sparsity_pattern.add(0, 0);
+ sparsity_pattern.add(1, 1);
+ sparsity_pattern.compress();
+
+ SparseMatrix<double> A(sparsity_pattern);
+ A.set(0, 0, 4.0);
+ A.set(1, 1, 4.0);
+
+ Vector<double> b(2);
+ b[0] = 1.0;
+ b[1] = 1.0;
+
+ const auto lo_A = linear_operator(A);
+
+ // As we all remember from numerical analysis class, CG will converge in
+ // at most two iterations
+ SolverControl solver_control_A(2, 1.0e-15);
+
+ SolverCG<Vector<double>> solver_A(solver_control_A);
+
+ const auto lo_A_inv = inverse_operator(lo_A, solver_A);
+ const auto lo_A_inv_t = transpose_operator(lo_A_inv);
+
+ deallog.depth_file(0);
+
+ unsigned int n_mistakes{0};
+
+ Vector<double> residual; // keep storage location to trigger bug.
+
+ for (unsigned int j = 0; j < 1000; ++j)
+ {
+ // test Tvmult:
+ residual = lo_A_inv_t * b;
+ residual -= answer;
+ if (residual.l2_norm() > 1e-10)
+ ++n_mistakes;
+
+ // test Tvmult_add:
+ residual = lo_A_inv_t * b - answer;
+ if (residual.l2_norm() > 1e-10)
+ ++n_mistakes;
+ }
+
+ deallog.depth_file(3);
+
+ deallog << "number of mistakes: " << n_mistakes << std::endl;
+ if (n_mistakes != 0)
+ deallog << "Ooops!" << std::endl;
+}