Interp1PrimFifthOrderWENO.c

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#include <stdlib.h>
#include <time.h>

#include <basic.h>
#include <arrayfunctions.h>
#include <mathfunctions.h>
#include <interpolation.h>
#include <mpivars.h>
#include <hypar.h>

#ifdef with_omp
#include <omp.h>
#endif

#undef  _MINIMUM_GHOSTS_

#define _MINIMUM_GHOSTS_ 3

int Interp1PrimFifthOrderWENO(
                                double *fI,  
                                double *fC,  
                                double *u,   
                                double *x,   
                                int    upw,  
                                int    dir,  
                                void   *s,   
                                void   *m,   
                                int    uflag 
                             )
{
  HyPar           *solver = (HyPar*)          s;
  WENOParameters  *weno   = (WENOParameters*) solver->interp;

  int ghosts = solver->ghosts;
  int ndims  = solver->ndims;
  int nvars  = solver->nvars;
  int *dim   = solver->dim_local;
  int *stride= solver->stride_with_ghosts;

  /* define some constants */
  static const double one_sixth          = 1.0/6.0;

  double *ww1, *ww2, *ww3;
  ww1 = weno->w1 + (upw < 0 ? 2*weno->size : 0) + (uflag ? weno->size : 0) + weno->offset[dir];
  ww2 = weno->w2 + (upw < 0 ? 2*weno->size : 0) + (uflag ? weno->size : 0) + weno->offset[dir];
  ww3 = weno->w3 + (upw < 0 ? 2*weno->size : 0) + (uflag ? weno->size : 0) + weno->offset[dir];

  /* create index and bounds for the outer loop, i.e., to loop over all 1D lines along
     dimension "dir"                                                                    */
  int indexC[ndims], indexI[ndims], index_outer[ndims], bounds_outer[ndims], bounds_inter[ndims];
  _ArrayCopy1D_(dim,bounds_outer,ndims); bounds_outer[dir] =  1;
  _ArrayCopy1D_(dim,bounds_inter,ndims); bounds_inter[dir] += 1;
  int N_outer; _ArrayProduct1D_(bounds_outer,ndims,N_outer);

#if defined(CPU_STAT)
  clock_t cpu_start, cpu_end;
  cpu_start = clock();
#endif

  int i;
#pragma omp parallel for schedule(auto) default(shared) private(i,index_outer,indexC,indexI)
  for (i=0; i<N_outer; i++) {
    _ArrayIndexnD_(ndims,i,bounds_outer,index_outer,0);
    _ArrayCopy1D_(index_outer,indexC,ndims);
    _ArrayCopy1D_(index_outer,indexI,ndims);
    for (indexI[dir] = 0; indexI[dir] < dim[dir]+1; indexI[dir]++) {
      int qm1,qm2,qm3,qp1,qp2,p;
      _ArrayIndex1D_(ndims,bounds_inter,indexI,0,p);
      if (upw > 0) {
        indexC[dir] = indexI[dir]-1; _ArrayIndex1D_(ndims,dim,indexC,ghosts,qm1);
        qm3 = qm1 - 2*stride[dir];
        qm2 = qm1 -   stride[dir];
        qp1 = qm1 +   stride[dir];
        qp2 = qm1 + 2*stride[dir];
      } else {
        indexC[dir] = indexI[dir]  ; _ArrayIndex1D_(ndims,dim,indexC,ghosts,qm1);
        qm3 = qm1 + 2*stride[dir];
        qm2 = qm1 +   stride[dir];
        qp1 = qm1 -   stride[dir];
        qp2 = qm1 - 2*stride[dir];
      }

      /* Defining stencil points */
      double *fm3, *fm2, *fm1, *fp1, *fp2;
      fm3 = (fC+qm3*nvars);
      fm2 = (fC+qm2*nvars);
      fm1 = (fC+qm1*nvars);
      fp1 = (fC+qp1*nvars);
      fp2 = (fC+qp2*nvars);

      /* Candidate stencils and their optimal weights*/
      double f1[nvars], f2[nvars], f3[nvars];
      _ArrayAXBYCZ_(f1,(2*one_sixth),fm3,(-7*one_sixth) ,fm2,(11*one_sixth) ,fm1,nvars);
      _ArrayAXBYCZ_(f2,(-one_sixth) ,fm2,(5*one_sixth)  ,fm1,(2*one_sixth)  ,fp1,nvars);
      _ArrayAXBYCZ_(f3,(2*one_sixth),fm1,(5*one_sixth)  ,fp1,(-one_sixth)   ,fp2,nvars);

      /* calculate WENO weights */
      double *w1,*w2,*w3;
      w1 = (ww1+p*nvars);
      w2 = (ww2+p*nvars);
      w3 = (ww3+p*nvars);

      _ArrayMultiply3Add1D_((fI+p*nvars),w1,f1,w2,f2,w3,f3,nvars);
    }
  }

#if defined(CPU_STAT)
  cpu_end = clock();
  printf("Interp1PrimFifthOrderWENO CPU time = %8.6lf dir = %d\n", (double)(cpu_end - cpu_start) / CLOCKS_PER_SEC, dir);
#endif

  return(0);
}