CalculateROMDiff.c File Reference

Computes the diff between PDE and ROM solutions. More...

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <basic.h>
#include <common.h>
#include <arrayfunctions.h>
#include <timeintegration.h>
#include <mpivars.h>
#include <hypar.h>

Go to the source code of this file.

Functions
int	CalculateROMDiff (void *s, void *m)

Detailed Description

Computes the diff between PDE and ROM solutions.

Author

Debojyoti Ghosh

Definition in file CalculateROMDiff.c.

Function Documentation

CalculateROMDiff()

int CalculateROMDiff	(	void *	s,
		void *	m
	)

Calculates the L1, L2, & Linf norms of the diff between the PDE solution and the predicted solution by libROM. error in the solution if the exact solution is

Parameters

s	Solver object of type HyPar
m	MPI object of type MPIVariables

Definition at line 24 of file CalculateROMDiff.c.

{
  HyPar* solver = (HyPar*) s;
  MPIVariables* mpi = (MPIVariables*) m;
  double sum = 0, global_sum = 0;

  static const double tolerance = 1e-15;

  int size = solver->npoints_local_wghosts * solver->nvars;
  double* u_diff = (double*) calloc (size, sizeof(double));

  /* calculate solution norms (for relative error) */
  double solution_norm[3] = {0.0,0.0,0.0};
  /* L1 */
  sum = ArraySumAbsnD ( solver->nvars,
                        solver->ndims,
                        solver->dim_local,
                        solver->ghosts,
                        solver->index,
                        solver->u );
  global_sum = 0; MPISum_double(&global_sum,&sum,1,&mpi->world);
  solution_norm[0] = global_sum/((double)solver->npoints_global);
  /* L2 */
  sum = ArraySumSquarenD  ( solver->nvars,
                            solver->ndims,
                            solver->dim_local,
                            solver->ghosts,
                            solver->index,
                            solver->u );
  global_sum = 0; MPISum_double(&global_sum,&sum,1,&mpi->world);
  solution_norm[1] = sqrt(global_sum/((double)solver->npoints_global));
  /* Linf */
  sum = ArrayMaxnD  ( solver->nvars,
                      solver->ndims,
                      solver->dim_local,
                      solver->ghosts,
                      solver->index
                      ,solver->u  );
  global_sum = 0; MPIMax_double(&global_sum,&sum,1,&mpi->world);
  solution_norm[2] = global_sum;

  /* set u_diff to PDE solution */
  _ArrayCopy1D_(solver->u, u_diff, size);
  /* subtract the ROM solutions */
  _ArrayAXPY_(solver->u_rom_predicted, -1.0, u_diff, size);

  /* calculate L1 norm of error */
  sum = ArraySumAbsnD ( solver->nvars,
                        solver->ndims,
                        solver->dim_local,
                        solver->ghosts,
                        solver->index,
                        u_diff  );
  global_sum = 0; MPISum_double(&global_sum,&sum,1,&mpi->world);
  solver->rom_diff_norms[0] = global_sum/((double)solver->npoints_global);

  /* calculate L2 norm of error */
  sum = ArraySumSquarenD  ( solver->nvars,
                            solver->ndims,
                            solver->dim_local,
                            solver->ghosts,
                            solver->index,
                            u_diff  );
  global_sum = 0; MPISum_double(&global_sum,&sum,1,&mpi->world);
  solver->rom_diff_norms[1] = sqrt(global_sum/((double)solver->npoints_global));

  /* calculate Linf norm of error */
  sum = ArrayMaxnD  ( solver->nvars,
                      solver->ndims,
                      solver->dim_local,
                      solver->ghosts,
                      solver->index,
                      u_diff  );
  global_sum = 0; MPIMax_double(&global_sum,&sum,1,&mpi->world);
  solver->rom_diff_norms[2] = global_sum;

  /* decide whether to normalize and report relative diff norms, 
    or report absolute diff norms. */
  if (    (solution_norm[0] > tolerance) 
      &&  (solution_norm[1] > tolerance) 
      &&  (solution_norm[2] > tolerance) ) {
    solver->rom_diff_norms[0] /= solution_norm[0];
    solver->rom_diff_norms[1] /= solution_norm[1];
    solver->rom_diff_norms[2] /= solution_norm[2];
  }

  free(u_diff);
  return 0;
}