[suitesparse] Add test for LDL wrapper

Signed-off-by: Christoph Grüninger <gruenich@dune-project.org>

dune/istl/test/ldltest.cc

+#include "config.h"
+#include<iostream>
+
+#include <dune/common/fmatrix.hh>
+#include <dune/common/fvector.hh>
+#include <dune/common/timer.hh>
+#include <dune/istl/bvector.hh>
+#include <dune/istl/colcompmatrix.hh>
+#include <dune/istl/io.hh>
+#include <dune/istl/operators.hh>
+#include <dune/istl/ldl.hh>
+
+#include "laplacian.hh"
+
+int main(int argc, char** argv)
+{
+  try
+  {
+    typedef double FIELD_TYPE;
+
+    const int BS=1;
+    std::size_t N=100;
+
+    if(argc>1)
+      N = atoi(argv[1]);
+    std::cout<<"testing for N="<<N<<" BS="<<1<<std::endl;
+
+    typedef Dune::FieldMatrix<FIELD_TYPE,BS,BS> MatrixBlock;
+    typedef Dune::BCRSMatrix<MatrixBlock> BCRSMat;
+    typedef Dune::FieldVector<FIELD_TYPE,BS> VectorBlock;
+    typedef Dune::BlockVector<VectorBlock> Vector;
+    typedef Dune::MatrixAdapter<BCRSMat,Vector,Vector> Operator;
+
+    BCRSMat mat;
+    Operator fop(mat);
+    Vector b(N*N), x(N*N);
+
+    setupLaplacian(mat,N);
+    b=1;
+    x=0;
+
+    Dune::Timer watch;
+
+    watch.reset();
+
+    Dune::LDL<BCRSMat> solver(mat,1);
+
+    Dune::InverseOperatorResult res;
+
+    Dune::LDL<BCRSMat> solver1;
+
+    std::set<std::size_t> mrs;
+    for(std::size_t s=0; s < N/2; ++s)
+      mrs.insert(s);
+
+    solver1.setSubMatrix(mat,mrs);
+    solver1.setVerbosity(true);
+
+    solver.apply(x,b, res);
+    solver.free();
+
+    Vector residuum(N*N);
+    residuum=0;
+    fop.apply(x,residuum);
+    residuum-=b;
+    std::cout<<"Residuum : "<<residuum.two_norm()<<std::endl;
+
+    solver1.apply(x,b, res);
+    solver1.apply(reinterpret_cast<FIELD_TYPE*>(&x[0]), reinterpret_cast<FIELD_TYPE*>(&b[0]));
+
+    return 0;
+  }
+  catch(Dune::Exception &e)
+  {
+    std::cerr << "Dune reported error: " << e << std::endl;
+  }
+  catch (...)
+  {}
+}