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