omgNeumann_ex1.C

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#include <mpi.h>
#include <cstdio>
#include "oda.h"
#include "omg.h"
#include "Point.h"
#include "parUtils.h"
#include "octUtils.h"
#include "TreeNode.h"
#include "handleStencils.h"
#include <cstdlib>
#include "sys.h"
#include "externVars.h"
#include <sstream>
#include "omgNeumann.h"

//Don't want time to be synchronized. Need to check load imbalance.
#ifdef MPI_WTIME_IS_GLOBAL
#undef MPI_WTIME_IS_GLOBAL
#endif

#ifdef PETSC_USE_LOG

int Jac2DiagEvent;
int Jac2MultEvent;
int Jac2FinestDiagEvent;
int Jac2FinestMultEvent;

#endif

const double w = 1;  // frequency for test purposes


void CalcConstCoef(const std::vector<double> & pts, std::vector<double> & coef)
{
  coef.assign(coef.size(),1.0);
}

void CalcVarRHS(const std::vector<double> & pts, std::vector<double> & rhs)
{
  for(int i=0,j=0; i<pts.size(); i+=3,j++)
   rhs[j] = (1 /*mass_factor*/ + 3*w*w*M_PI*M_PI) * cos(w*M_PI*pts[i])* cos(w*M_PI*pts[i+1])*cos(w*M_PI*pts[i+2]);      
}

int main(int argc, char ** argv )
{
  PetscInitialize(&argc,&argv,"options","DENDRO example\n");
  ot::RegisterEvents();

  ot::DAMG_Initialize(MPI_COMM_WORLD);

  int size, rank;
  MPI_Comm_size(MPI_COMM_WORLD,&size);
  MPI_Comm_rank(MPI_COMM_WORLD,&rank);

  if (argc<2) 
  {
    std::cout<<"Usage: mpirun -np <numProcs> "<<argv[0]<<" <filePrefix>"<<std::endl;
    return(-1);
  }

  std::ostringstream fName;
  fName<<argv[1]<<rank<<"_"<<size<<".pts";

  std::vector<double> pts;
  ot::readPtsFromFile(const_cast<char*>(fName.str().c_str()), pts);
  
  Vec sol;
  ot::DAMG * damg;
  
  // This function pointer will be called while setting up the solver on the coarsest grid if not all processes are active on the coarse grid 
  ot::getPrivateMatricesForKSP_Shell = getPrivateMatricesForKSP_Shell_Jac2;

  solve_neumann(
    /* input parameters: */
     pts,
     CalcConstCoef,
     CalcVarRHS,
     30, /* upper bound */

     /* output parameters */
     sol,
     damg
    );
 
  // compare solution with the exact one
  unsigned numMultigridLevels = damg[0]->totalLevels;
  ot::DA* da=damg[numMultigridLevels-1]->da;
  PetscScalar *solArray;
  da->vecGetBuffer(sol,solArray,false,false,true,1);
  double maxDiff = 0;
  unsigned maxDepth=da->getMaxDepth()-1;

  if(da->iAmActive())
  { 
    // first loop over those octants which do not contain ghost nodes.
    for(da->init<ot::DA_FLAGS::INDEPENDENT>(); da->curr() < da->end<ot::DA_FLAGS::INDEPENDENT>(); da->next<ot::DA_FLAGS::INDEPENDENT>())  
    {
      Point pt = da->getCurrentOffset();
      unsigned levelhere = da->getLevel(da->curr()) - 1;
      double hxOct = ldexp(1.0,-levelhere);
      double x = ldexp(pt.x(),-maxDepth );
      double y = ldexp(pt.y(),-maxDepth );
      double z = ldexp(pt.z(),-maxDepth );

      unsigned int indices[8];
      da->getNodeIndices(indices); 

      double coord[8][3] = {
        {0.0,0.0,0.0},
        {1.0,0.0,0.0},
        {0.0,1.0,0.0},
        {1.0,1.0,0.0},
        {0.0,0.0,1.0},
        {1.0,0.0,1.0},
        {0.0,1.0,1.0},
        {1.0,1.0,1.0}
      };

      unsigned char hn = da->getHangingNodeIndex(da->curr());

      for(int i = 0; i < 8; i++)
        if (!(hn & (1 << i)))
        {
          double xhere, yhere, zhere;
          xhere = x + coord[i][0]*hxOct; 
          yhere = y + coord[i][1]*hxOct; 
          zhere = z + coord[i][2]*hxOct; 

          double currDiff = fabs ( solArray[indices[i]] - cos(w*M_PI*xhere)*cos(w*M_PI*yhere)*cos(w*M_PI*zhere) );      
          if (maxDiff < currDiff)
            maxDiff=currDiff;
        }
    }  
    
    // now loop over those octants which DO contain ghost nodes; now we need to  check if the node is ghost, and skip it if it is
    size_t myFirstNode = da->getIdxElementBegin();
    size_t postFirstNode = da->getIdxPostGhostBegin();
    for(da->init<ot::DA_FLAGS::DEPENDENT>(); da->curr() < da->end<ot::DA_FLAGS::DEPENDENT>(); da->next<ot::DA_FLAGS::DEPENDENT>())  
    {
      Point pt = da->getCurrentOffset();
      unsigned levelhere = da->getLevel(da->curr()) - 1;
      double hxOct = ldexp(1.0,-levelhere);
      double x = ldexp(pt.x(),-maxDepth );
      double y = ldexp(pt.y(),-maxDepth );
      double z = ldexp(pt.z(),-maxDepth );

      unsigned int indices[8];
      da->getNodeIndices(indices); 

      double coord[8][3] = {
        {0.0,0.0,0.0},
        {1.0,0.0,0.0},
        {0.0,1.0,0.0},
        {1.0,1.0,0.0},
        {0.0,0.0,1.0},
        {1.0,0.0,1.0},
        {0.0,1.0,1.0},
        {1.0,1.0,1.0}
      };

      unsigned char hn = da->getHangingNodeIndex(da->curr());

      for(int i = 0; i < 8; i++)
        if ( indices[i]>=myFirstNode && indices[i]<postFirstNode && !(hn & (1 << i)) )
        {
          double xhere, yhere, zhere;
          xhere = x + coord[i][0]*hxOct; 
          yhere = y + coord[i][1]*hxOct; 
          zhere = z + coord[i][2]*hxOct; 

          double currDiff = fabs ( solArray[indices[i]] - cos(w*M_PI*xhere)*cos(w*M_PI*yhere)*cos(w*M_PI*zhere) );      
          if (maxDiff < currDiff)
             maxDiff=currDiff;
        }
    }  
  }
  da->vecRestoreBuffer(sol,solArray,false,false,true,1); 

    double gMaxDiff;
    par::Mpi_Reduce<double>(&maxDiff, &gMaxDiff, 1, MPI_MAX, 0, MPI_COMM_WORLD);  
  if (!rank)
  {
    std::cout<<"Maximum difference: "<<gMaxDiff<<std::endl;
  }
    
  double solmax,solmin;
  VecMax(sol,NULL,&solmax);
  VecMin(sol,NULL,&solmin);

  if (!rank)
    std::cout<<"solution min: " << solmin << "; solution max: " << solmax << std::endl;

  // destroy multigrid context; this destroys the solution as well 
  DAMGDestroy(damg);
  
  ot::DAMG_Finalize();
  PetscFinalize();
  return 0;
}

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