experimental wrapper for the ISTL SeqILU0 preconditioner

[[Imported from SVN: r3133]]

dune-solvers/iterationsteps/istlseqilu0step.hh

+#ifndef ISTL_SEQILU0_STEP_HH
+#define ISTL_SEQILU0_STEP_HH
+
+/** \file 
+    \brief A wrapper class for the ISTL SeqILU0 implementation
+ */
+
+#include <memory>
+
+#include <dune-solvers/iterationsteps/lineariterationstep.hh>
+
+#include <dune/istl/preconditioners.hh>
+#include <dune/istl/operators.hh>
+
+/** \brief A wrapper class for the ISTL SeqILU0 implementation
+ */
+template <class MatrixType, class VectorType>
+class ISTLSeqILU0Step
+    : public LinearIterationStep<MatrixType, VectorType>
+{
+    typedef Dune::MatrixAdapter<MatrixType,VectorType,VectorType> Operator;
+
+    typedef Dune::SeqILU0<MatrixType,VectorType,VectorType> SeqILU0;
+
+public:
+
+    /** \brief Constructor which initializes and sets up an algebraic hierarchy
+        \param smootherArgs  Arguments for the smoother.  See the dune-istl documentation for details
+        \param coarseningCriterion  Arguments for the coarsening.  See the dune-istl documentation for details
+     */
+    ISTLSeqILU0Step (const MatrixType* stiffnessMatrix, 
+                     VectorType& x, 
+                     VectorType& rhs,
+                     double relaxationFactor)
+        : relaxationFactor_(relaxationFactor)
+    {
+        setProblem(*stiffnessMatrix, x, rhs);
+
+        seqILU0_ = std::auto_ptr<SeqILU0>(new SeqILU0(*stiffnessMatrix, relaxationFactor));
+        seqILU0_->pre(*this->x_,*this->rhs_);
+    }
+
+    /** \brief Initialize the iteration step but don't actually build the matrix hierarchy yet */
+    ISTLSeqILU0Step (const MatrixType* stiffnessMatrix, 
+             VectorType& x, 
+             VectorType& rhs)
+    {
+        setProblem(*stiffnessMatrix, x, rhs);
+    }
+
+    /** \brief Sets up an algebraic hierarchy
+     */
+    virtual void preprocess();
+
+    /** \brief Perform one iteration */
+    virtual void iterate();
+
+    /** \brief Get the solution */
+    virtual VectorType getSol();
+
+private:
+
+    /** \brief The dune-istl sequential ILU0 preconditioner */
+    std::auto_ptr<SeqILU0> seqILU0_;
+
+    /** \brief Some magic relaxation factor */
+    double relaxationFactor_;
+};
+
+template <class MatrixType, class VectorType>
+void ISTLSeqILU0Step<MatrixType,VectorType>::preprocess()
+{
+    seqILU0_ = std::auto_ptr<SeqILU0>(new SeqILU0(*this->mat_, relaxationFactor_));
+    seqILU0_->pre(*this->x_,*this->rhs_);
+}
+
+template <class MatrixType, class VectorType>
+void ISTLSeqILU0Step<MatrixType,VectorType>::iterate()
+{
+    seqILU0_->apply(*this->x_,*this->rhs_);
+}
+
+template <class MatrixType, class VectorType>
+VectorType ISTLSeqILU0Step<MatrixType,VectorType>::getSol()
+{
+    return *this->x_;
+}
+
+#endif