1 static char help[]="This program illustrates the use of PETSc-fftw interface for sequential real DFT\n"; 2 #include <petscmat.h> 3 #include <fftw3-mpi.h> 4 int main(int argc,char **args) 5 { 6 PetscErrorCode ierr; 7 PetscMPIInt rank,size; 8 PetscInt N0=10,N1=10,N2=10,N3=10,N4=10,N=N0*N1*N2*N3*N4; 9 PetscRandom rdm; 10 PetscReal enorm; 11 Vec x,y,z,input,output; 12 Mat A; 13 PetscInt DIM, dim[5],vsize; 14 PetscReal fac; 15 16 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 17 #if defined(PETSC_USE_COMPLEX) 18 SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers"); 19 #endif 20 CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 21 CHKERRMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank)); 22 23 PetscCheckFalse(size!=1,PETSC_COMM_WORLD,PETSC_ERR_SUP, "This is a uni-processor example only"); 24 CHKERRQ(PetscRandomCreate(PETSC_COMM_SELF, &rdm)); 25 CHKERRQ(PetscRandomSetFromOptions(rdm)); 26 CHKERRQ(VecCreate(PETSC_COMM_SELF,&input)); 27 CHKERRQ(VecSetSizes(input,N,N)); 28 CHKERRQ(VecSetFromOptions(input)); 29 CHKERRQ(VecSetRandom(input,rdm)); 30 CHKERRQ(VecDuplicate(input,&output)); 31 32 DIM = 5; dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4; 33 CHKERRQ(MatCreateFFT(PETSC_COMM_SELF,DIM,dim,MATFFTW,&A)); 34 CHKERRQ(MatCreateVecs(A,&x,&y)); 35 CHKERRQ(MatCreateVecs(A,&z,NULL)); 36 37 CHKERRQ(VecGetSize(x,&vsize)); 38 printf("The vector size of input from the main routine is %d\n",vsize); 39 40 CHKERRQ(VecGetSize(z,&vsize)); 41 printf("The vector size of output from the main routine is %d\n",vsize); 42 43 CHKERRQ(InputTransformFFT(A,input,x)); 44 45 CHKERRQ(MatMult(A,x,y)); 46 CHKERRQ(MatMultTranspose(A,y,z)); 47 48 CHKERRQ(OutputTransformFFT(A,z,output)); 49 fac = 1.0/(PetscReal)N; 50 CHKERRQ(VecScale(output,fac)); 51 /* 52 CHKERRQ(VecAssemblyBegin(input)); 53 CHKERRQ(VecAssemblyEnd(input)); 54 CHKERRQ(VecAssemblyBegin(output)); 55 CHKERRQ(VecAssemblyEnd(output)); 56 57 CHKERRQ(VecView(input,PETSC_VIEWER_STDOUT_WORLD)); 58 CHKERRQ(VecView(output,PETSC_VIEWER_STDOUT_WORLD)); 59 */ 60 CHKERRQ(VecAXPY(output,-1.0,input)); 61 CHKERRQ(VecNorm(output,NORM_1,&enorm)); 62 /* if (enorm > 1.e-14) { */ 63 CHKERRQ(PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm)); 64 /* } */ 65 66 CHKERRQ(VecDestroy(&output)); 67 CHKERRQ(VecDestroy(&input)); 68 CHKERRQ(VecDestroy(&x)); 69 CHKERRQ(VecDestroy(&y)); 70 CHKERRQ(VecDestroy(&z)); 71 CHKERRQ(MatDestroy(&A)); 72 CHKERRQ(PetscRandomDestroy(&rdm)); 73 ierr = PetscFinalize(); 74 return ierr; 75 76 } 77