Newton.h 3.17 KB
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// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ==  http://www.amdis-fem.org                                              ==
// ==                                                                        ==
// ============================================================================
//
// Software License for AMDiS
//
// Copyright (c) 2010 Dresden University of Technology 
// All rights reserved.
// Authors: Simon Vey, Thomas Witkowski et al.
//
// This file is part of AMDiS
//
// See also license.opensource.txt in the distribution.



/** \file Newton.h */

#ifndef AMDIS_NEWTON_H
#define AMDIS_NEWTON_H

#include "CreatorInterface.h"
#include "NonLinSolver.h"
#include "OEMSolver.h"
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#include "io/VtkWriter.h"
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namespace AMDiS {

  /**
   * \ingroup Solver
   * 
   * \Brief
   * Implements the newton method for solving a non linear system. Sub class of
   * NonLinSolver.
   */
  class Newton : public NonLinSolver
  {
  public:
    /// Creator class used in the NonLinSolverMap.
    class Creator : public NonLinSolverCreator
    {
    public:
      virtual ~Creator() {}

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      /// Returns a new Newton object.
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      NonLinSolver* create() 
      { 
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	return new Newton(this->name, this->linearSolver); 
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      }
    };

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    /// Calls constructor of base class NonLinSolver
    Newton(const std::string& name, OEMSolver *linSolver)
      : NonLinSolver(name, linSolver),
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	b(NULL)
    {}

  private:
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    /// Realisation of NonLinSolver::init
    void init() {}
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    /// realisation of NonLinSolver::nlsolve
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    int nlsolve(SolverMatrix<Matrix<DOFMatrix*> >& mat,
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		SystemVector& x, SystemVector& rhs, 
		AdaptInfo *adaptInfo,
		ProblemStat *prob)
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    {
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      FUNCNAME("Newton::nlsolve()");
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      if (b == NULL)
	b = new SystemVector(x);
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      double err = 0.0, errOld = -1.0;
      int iter, n;
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      MSG("iter. |     this->residual |     red. |    n |\n");
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      for (iter = 1; iter <= this->maxIter; iter++) {
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	// Assemble DF(x) and F(x)
	prob->buildAfterCoarsen(adaptInfo, 0, true, true);

	// Initial guess is zero
	b->set(0.0);

	// Solve linear system
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	n = solveLinearSystem(mat, *b, rhs);
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	// x = x + d
	x += *b;
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	if (this->usedNorm == NO_NORM || this->usedNorm == L2_NORM)
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	  err = L2Norm(b);
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	else
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	  err = H1Norm(b);
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	if (iter == 1)  
	  this->initialResidual = err;
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	if (errOld <= 0)
	  MSG("%5d | %12.5e | -------- | %4d |\n", iter, err, n);
	else
	  MSG("%5d | %12.5e | %8.2e | %4d |\n", iter, err, err/errOld, n);	

	residual = err;
 	if (err < this->tolerance) {
 	  MSG("Finished successfully!\n");
 	  return iter;
 	}
	errOld = err;
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      }

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      MSG("iter. %d, residual: %12.5e\n", iter, err);
      MSG("tolerance %e not reached\n", this->tolerance);
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      this->residual = err;

      return iter;
    }

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    /// Realisation of NonLinSolver::exit
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    void exit()
    {
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      if (b != NULL) {
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	delete b;
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	b = NULL;
      }
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    }

  private:
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    /// Internal used data
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    SystemVector *b;
  };

}

#endif // AMDIS_NEWTON_H