Date: 2013-07-02T14:44:23+00:00

Actual source code: ex157.c
petsc-3.4.2 2013-07-02

      1: static char help[]="This program illustrates the use of PETSc-fftw interface for parallel real DFT\n";
      2: #include <petscmat.h>
      3: #include <fftw3-mpi.h>
      6: PetscInt main(PetscInt argc,char **args)
      7: {
      9:   PetscMPIInt    rank,size;
     10:   PetscInt       N0=2048,N1=2048,N2=3,N3=5,N4=5,N=N0*N1;
     11:   PetscRandom    rdm;
     12:   PetscReal      enorm;
     13:   Vec            x,y,z,input,output;
     14:   Mat            A;
     15:   PetscInt       DIM, dim[5],vsize;
     16:   PetscReal      fac;
     17:   PetscScalar    one=1,two=2,three=3;

     19:   PetscInitialize(&argc,&args,(char*)0,help);
     20:   MPI_Comm_size(PETSC_COMM_WORLD, &size);
     21:   MPI_Comm_rank(PETSC_COMM_WORLD, &rank);

     23: /* #if !defined(PETSC_USE_COMPLEX) */
     24: /*  SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "Example for Complex DFT. Your current data type is real"); */
     25: /* #endif */
     26:   PetscRandomCreate(PETSC_COMM_WORLD, &rdm);
     27:   PetscRandomSetFromOptions(rdm);
     28:   VecCreate(PETSC_COMM_WORLD,&input);
     29:   VecSetSizes(input,PETSC_DECIDE,N);
     30:   VecSetFromOptions(input);
     31: /*  VecSet(input,one); */
     32: /*  VecSetValue(input,1,two,INSERT_VALUES); */
     33: /*  VecSetValue(input,2,three,INSERT_VALUES); */
     34: /*  VecSetValue(input,3,three,INSERT_VALUES); */
     35:   VecSetRandom(input,rdm);
     36: /*  VecSetRandom(input,rdm); */
     37: /*  VecSetRandom(input,rdm); */
     38:   VecDuplicate(input,&output);

     40:   DIM  = 2; dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4;
     41:   MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A);
     42:   MatGetVecsFFTW(A,&x,&y,&z);
     43: /*  MatGetVecs(A,&x,&y); */
     44: /*  MatGetVecs(A,&z,NULL); */

     46:   VecGetSize(x,&vsize);
     47:   printf("The vector size  of input from the main routine is %d\n",vsize);

     49:   VecGetSize(z,&vsize);
     50:   printf("The vector size of output from the main routine is %d\n",vsize);

     52:   InputTransformFFT(A,input,x);

     54:   MatMult(A,x,y);
     55:   VecAssemblyBegin(y);
     56:   VecAssemblyEnd(y);
     57:   VecView(y,PETSC_VIEWER_STDOUT_WORLD);

     59:   MatMultTranspose(A,y,z);

     61:   OutputTransformFFT(A,z,output);
     62:   fac  = 1.0/(PetscReal)N;
     63:   VecScale(output,fac);

     65:   VecAssemblyBegin(input);
     66:   VecAssemblyEnd(input);
     67:   VecAssemblyBegin(output);
     68:   VecAssemblyEnd(output);

     70: /*  VecView(input,PETSC_VIEWER_STDOUT_WORLD); */
     71: /*  VecView(output,PETSC_VIEWER_STDOUT_WORLD); */

     73:   VecAXPY(output,-1.0,input);
     74:   VecNorm(output,NORM_1,&enorm);
     75: /*  if (enorm > 1.e-14) { */
     76:   PetscPrintf(PETSC_COMM_SELF,"  Error norm of |x - z| %e\n",enorm);
     77: /*      } */

     79:   VecDestroy(&output);
     80:   VecDestroy(&input);
     81:   VecDestroy(&x);
     82:   VecDestroy(&y);
     83:   VecDestroy(&z);
     84:   MatDestroy(&A);
     85:   PetscRandomDestroy(&rdm);
     86:   PetscFinalize();
     87:   return 0;

     89: }