Actual source code: ex146.c

  1: /* This program illustrates use of paralllel real FFT*/
  2: static char help[]="This program illustrates the use of parallel real 3D fftw (without PETSc interface)";
  3: #include <petscmat.h>
  4: #include <fftw3.h>
  5: #include <fftw3-mpi.h>

  7: int main(int argc,char **args)
  8: {
  9:   ptrdiff_t      N0=256,N1=256,N2=256,N3=2,dim[4];
 10:   fftw_plan      bplan,fplan;
 11:   fftw_complex   *out;
 12:   double         *in1,*in2;
 13:   ptrdiff_t      alloc_local,local_n0,local_0_start;
 14:   ptrdiff_t      local_n1,local_1_start;
 15:   PetscInt       i,j,indx,n1;
 16:   PetscInt       size,rank,n,N,*in,N_factor,NM;
 17:   PetscScalar    *data_fin,value1,one=1.57,zero=0.0;
 18:   PetscScalar    a,*x_arr,*y_arr,*z_arr,enorm;
 19:   Vec            fin,fout,fout1,ini,final;
 20:   PetscRandom    rnd;
 21:   VecScatter     vecscat,vecscat1;
 22:   IS             indx1,indx2;
 23:   PetscInt       *indx3,k,l,*indx4;
 24:   PetscInt       low,tempindx,tempindx1;

 26:   PetscInitialize(&argc,&args,(char*)0,help);
 27: #if defined(PETSC_USE_COMPLEX)
 28:   SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers. Your current scalar type is complex");
 29: #endif
 30:   MPI_Comm_size(PETSC_COMM_WORLD, &size);
 31:   MPI_Comm_rank(PETSC_COMM_WORLD, &rank);

 33:   PetscRandomCreate(PETSC_COMM_WORLD,&rnd);

 35:   alloc_local = fftw_mpi_local_size_3d_transposed(N0,N1,N2/2+1,PETSC_COMM_WORLD,&local_n0,&local_0_start,&local_n1,&local_1_start);

 37: /*    printf("The value alloc_local is %ld from process %d\n",alloc_local,rank);     */
 38:   printf("The value local_n0 is %ld from process %d\n",local_n0,rank);
 39: /*    printf("The value local_0_start is  %ld from process %d\n",local_0_start,rank);*/
 40: /*    printf("The value local_n1 is  %ld from process %d\n",local_n1,rank);          */
 41: /*    printf("The value local_1_start is  %ld from process %d\n",local_1_start,rank);*/

 43:   /* Allocate space for input and output arrays  */

 45:   in1=(double*)fftw_malloc(sizeof(double)*alloc_local*2);
 46:   in2=(double*)fftw_malloc(sizeof(double)*alloc_local*2);
 47:   out=(fftw_complex*)fftw_malloc(sizeof(fftw_complex)*alloc_local);

 49:   N=2*N0*N1*(N2/2+1);N_factor=N0*N1*N2;
 50:   n=2*local_n0*N1*(N2/2+1);n1=local_n1*N0*2*N1;

 52: /*    printf("The value N is  %d from process %d\n",N,rank);   */
 53: /*    printf("The value n is  %d from process %d\n",n,rank);   */
 54: /*    printf("The value n1 is  %d from process %d\n",n1,rank); */
 55:   /* Creating data vector and accompanying array with VeccreateMPIWithArray */
 56:   VecCreateMPIWithArray(PETSC_COMM_WORLD,1,n,N,(PetscScalar*)in1,&fin);
 57:   VecCreateMPIWithArray(PETSC_COMM_WORLD,1,n,N,(PetscScalar*)out,&fout);
 58:   VecCreateMPIWithArray(PETSC_COMM_WORLD,1,n,N,(PetscScalar*)in2,&fout1);

 60: /*    VecGetSize(fin,&size); */
 61: /*    printf("The size is %d\n",size); */

 63:   VecSet(fin,one);
 64:   VecSet(fout,zero);
 65:   VecSet(fout1,zero);

 67:   VecAssemblyBegin(fin);
 68:   VecAssemblyEnd(fin);
 69: /*    VecView(fin,PETSC_VIEWER_STDOUT_WORLD); */

 71:   VecGetArray(fin,&x_arr);
 72:   VecGetArray(fout1,&z_arr);
 73:   VecGetArray(fout,&y_arr);

 75:   fplan=fftw_mpi_plan_dft_r2c_3d(N0,N1,N2,(double*)x_arr,(fftw_complex*)y_arr,PETSC_COMM_WORLD,FFTW_ESTIMATE);
 76:   bplan=fftw_mpi_plan_dft_c2r_3d(N0,N1,N2,(fftw_complex*)y_arr,(double*)z_arr,PETSC_COMM_WORLD,FFTW_ESTIMATE);

 78:   fftw_execute(fplan);
 79:   fftw_execute(bplan);

 81:   VecRestoreArray(fin,&x_arr);
 82:   VecRestoreArray(fout1,&z_arr);
 83:   VecRestoreArray(fout,&y_arr);

 85: /*    a = 1.0/(PetscReal)N_factor; */
 86: /*    VecScale(fout1,a); */
 87:   VecCreate(PETSC_COMM_WORLD,&ini);
 88:   VecCreate(PETSC_COMM_WORLD,&final);
 89:   VecSetSizes(ini,local_n0*N1*N2,N_factor);
 90:   VecSetSizes(final,local_n0*N1*N2,N_factor);
 91: /*    VecSetSizes(ini,PETSC_DECIDE,N_factor); */
 92: /*    VecSetSizes(final,PETSC_DECIDE,N_factor); */
 93:   VecSetFromOptions(ini);
 94:   VecSetFromOptions(final);

 96:   if (N2%2==0) NM=N2+2;
 97:   else NM=N2+1;

 99:   VecGetOwnershipRange(fin,&low,NULL);
100:   printf("The local index is %d from %d\n",low,rank);
101:   PetscMalloc1(local_n0*N1*N2,&indx3);
102:   PetscMalloc1(local_n0*N1*N2,&indx4);
103:   for (i=0; i<local_n0; i++) {
104:     for (j=0;j<N1;j++) {
105:       for (k=0;k<N2;k++) {
106:         tempindx  = i*N1*N2 + j*N2 + k;
107:         tempindx1 = i*N1*NM + j*NM + k;

109:         indx3[tempindx]=local_0_start*N1*N2+tempindx;
110:         indx4[tempindx]=low+tempindx1;
111:       }
112:       /*          printf("index3 %d from proc %d is \n",indx3[tempindx],rank); */
113:       /*          printf("index4 %d from proc %d is \n",indx4[tempindx],rank); */
114:     }
115:   }
116:   VecGetValues(fin,local_n0*N1*N2,indx4,x_arr);
117:   VecSetValues(ini,local_n0*N1*N2,indx3,x_arr,INSERT_VALUES);
118:   VecAssemblyBegin(ini);
119:   VecAssemblyEnd(ini);

121:   VecGetValues(fout1,local_n0*N1*N2,indx4,y_arr);
122:   VecSetValues(final,local_n0*N1*N2,indx3,y_arr,INSERT_VALUES);
123:   VecAssemblyBegin(final);
124:   VecAssemblyEnd(final);

126:   printf("The local index value is %ld from %d",local_n0*N1*N2,rank);
127: /*
128:   for (i=0;i<N0;i++) {
129:      for (j=0;j<N1;j++) {
130:         indx=i*N1*NM+j*NM;
131:         ISCreateStride(PETSC_COMM_WORLD,N2,indx,1,&indx1);
132:         indx=i*N1*N2+j*N2;
133:         ISCreateStride(PETSC_COMM_WORLD,N2,indx,1,&indx2);
134:         VecScatterCreate(fin,indx1,ini,indx2,&vecscat);
135:         VecScatterBegin(vecscat,fin,ini,INSERT_VALUES,SCATTER_FORWARD);
136:         VecScatterEnd(vecscat,fin,ini,INSERT_VALUES,SCATTER_FORWARD);
137:         VecScatterCreate(fout1,indx1,final,indx2,&vecscat1);
138:         VecScatterBegin(vecscat1,fout1,final,INSERT_VALUES,SCATTER_FORWARD);
139:         VecScatterEnd(vecscat1,fout1,final,INSERT_VALUES,SCATTER_FORWARD);
140:      }
141:   }
142: */
143:   a    = 1.0/(PetscReal)N_factor;
144:   VecScale(fout1,a);
145:   VecScale(final,a);

147:   VecAssemblyBegin(ini);
148:   VecAssemblyEnd(ini);

150:   VecAssemblyBegin(final);
151:   VecAssemblyEnd(final);

153: /*    VecView(final,PETSC_VIEWER_STDOUT_WORLD); */
154:   VecAXPY(final,-1.0,ini);
155:   VecNorm(final,NORM_1,&enorm);
156:   PetscPrintf(PETSC_COMM_WORLD,"  Error norm of |x - z|  = %e\n",enorm);
157:   fftw_destroy_plan(fplan);
158:   fftw_destroy_plan(bplan);
159:   fftw_free(in1); VecDestroy(&fin);
160:   fftw_free(out); VecDestroy(&fout);
161:   fftw_free(in2); VecDestroy(&fout1);

163:   PetscFinalize();
164:   return 0;
165: }