/**
 * @file   com_check_relative_residual.cpp
 * @author Julian Iseringhausen <isering@ins.uni-bonn.de>
 * @date   Mon Apr 18 12:30:18 2011
 *
 * @brief  Checks if the relative residual is small enough
 *         to stop execution.
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <cmath>
#include <cstdio>

#include "base/command.hpp"
#include "base/factory.hpp"
#include "base/object.hpp"
#include "comm/comm.hpp"
#include "grid/multigrid.hpp"
#include "mg.hpp"

using namespace VMG;

class VMGCommandCheckRelativeResidual : public Command
{
public:
  Request Run(Command::argument_vector arguments)
  {
    VMG::Comm* comm = MG::GetComm();
    VMG::Factory& factory = MG::GetFactory();

    const vmg_float res = comm->ComputeResidualNorm(*MG::GetSol(), *MG::GetRhs());
    const vmg_float& init_res = factory.GetObject(arguments[0])->Cast< ObjectStorage<vmg_float> >()->Val();
    const vmg_float& precision = factory.GetObject("PRECISION")->Cast< ObjectStorage<vmg_float> >()->Val();
    const vmg_float rel_res = fabs(res / init_res);

    if (comm->Rank() == 0)
      printf("Multigrid: Relative residual: %e\n", rel_res);

    if (rel_res < precision)
      return StopCycleLater;
    else
      return Continue;
  }

  static const char* Name() {return "CheckRelativeResidual";}
  static int Arguments() {return 1;}
};

CREATE_INITIALIZER(VMGCommandCheckRelativeResidual);