--- /dev/null
+//---------------------------- petsc_solver_03_precondition_lu.cc ---------------------------
+// $Id$
+// Version: $Name$
+//
+// Copyright (C) 2004, 2005, 2010, 2012 by the deal.II authors
+//
+// This file is subject to QPL and may not be distributed
+// without copyright and license information. Please refer
+// to the file deal.II/doc/license.html for the text and
+// further information on this license.
+//
+//---------------------------- petsc_solver_03_precondition_lu.cc ---------------------------
+
+// test the PETSc CG solver with the PreconditionLU
+// preconditioner. This should converge in exactly one iteration
+
+
+#include "../tests.h"
+#include "../lac/testmatrix.h"
+#include <cmath>
+#include <fstream>
+#include <iostream>
+#include <iomanip>
+#include <deal.II/base/logstream.h>
+#include <deal.II/lac/petsc_sparse_matrix.h>
+#include <deal.II/lac/petsc_vector.h>
+#include <deal.II/lac/petsc_solver.h>
+#include <deal.II/lac/petsc_precondition.h>
+#include <deal.II/lac/vector_memory.h>
+#include <typeinfo>
+
+template<class SOLVER, class MATRIX, class VECTOR, class PRECONDITION>
+void
+check_solve( SOLVER& solver, const MATRIX& A,
+ VECTOR& u, VECTOR& f, const PRECONDITION& P)
+{
+ deallog << "Solver type: " << typeid(solver).name() << std::endl;
+
+ u = 0.;
+ f = 1.;
+ try
+ {
+ solver.solve(A,u,f,P);
+ }
+ catch (std::exception& e)
+ {
+ deallog << e.what() << std::endl;
+ abort ();
+ }
+
+ deallog << "Solver stopped after " << solver.control().last_step()
+ << " iterations" << std::endl;
+
+ // we use a direct solver as a
+ // preconditioner. this should
+ // converge in one step!
+ Assert (solver.control().last_step() == 1,
+ ExcInternalError());
+}
+
+
+int main(int argc, char **argv)
+{
+ std::ofstream logfile("solver_03_precondition_lu/output");
+ deallog.attach(logfile);
+ deallog << std::setprecision(4);
+ deallog.depth_console(0);
+ deallog.threshold_double(1.e-10);
+
+ PetscInitialize(&argc,&argv,0,0);
+ {
+ SolverControl control(100, 1.e-3);
+
+ const unsigned int size = 32;
+ unsigned int dim = (size-1)*(size-1);
+
+ deallog << "Size " << size << " Unknowns " << dim << std::endl;
+
+ // Make matrix
+ FDMatrix testproblem(size, size);
+ PETScWrappers::SparseMatrix A(dim, dim, 5);
+ testproblem.five_point(A);
+
+ PETScWrappers::Vector f(dim);
+ PETScWrappers::Vector u(dim);
+ f = 1.;
+ A.compress ();
+ f.compress ();
+ u.compress ();
+
+ PETScWrappers::SolverCG solver(control);
+ PETScWrappers::PreconditionLU preconditioner(A);
+ check_solve (solver, A,u,f, preconditioner);
+ }
+ PetscFinalize ();
+}
+