1 static char help[]="This program illustrates the use of PETSc-fftw interface for real DFT\n"; 2 #include <petscmat.h> 3 #include <fftw3-mpi.h> 4 5 extern PetscErrorCode InputTransformFFT(Mat,Vec,Vec); 6 extern PetscErrorCode OutputTransformFFT(Mat,Vec,Vec); 7 int main(int argc,char **args) 8 { 9 PetscErrorCode ierr; 10 PetscMPIInt rank,size; 11 PetscInt N0=3,N1=3,N2=3,N3=3,N4=3,N=N0*N1*N2*N3; 12 PetscRandom rdm; 13 PetscReal enorm; 14 Vec x,y,z,input,output; 15 Mat A; 16 PetscInt DIM, dim[5],vsize; 17 PetscReal fac; 18 PetscScalar one=1; 19 20 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 21 #if defined(PETSC_USE_COMPLEX) 22 SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This example requires real numbers"); 23 #endif 24 25 ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRMPI(ierr); 26 ierr = MPI_Comm_rank(PETSC_COMM_WORLD, &rank);CHKERRMPI(ierr); 27 28 ierr = PetscRandomCreate(PETSC_COMM_WORLD, &rdm);CHKERRQ(ierr); 29 ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr); 30 ierr = VecCreate(PETSC_COMM_WORLD,&input);CHKERRQ(ierr); 31 ierr = VecSetSizes(input,PETSC_DECIDE,N);CHKERRQ(ierr); 32 ierr = VecSetFromOptions(input);CHKERRQ(ierr); 33 ierr = VecSetRandom(input,rdm);CHKERRQ(ierr); 34 ierr = VecAssemblyBegin(input);CHKERRQ(ierr); 35 ierr = VecAssemblyEnd(input);CHKERRQ(ierr); 36 /* ierr = VecView(input,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); */ 37 ierr = VecDuplicate(input,&output);CHKERRQ(ierr); 38 39 DIM = 4; 40 dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4; 41 42 ierr = MatCreateFFT(PETSC_COMM_WORLD,DIM,dim,MATFFTW,&A);CHKERRQ(ierr); 43 ierr = MatCreateVecs(A,&x,&y);CHKERRQ(ierr); 44 ierr = MatCreateVecs(A,&z,NULL);CHKERRQ(ierr); 45 ierr = VecGetSize(x,&vsize);CHKERRQ(ierr); 46 printf("The vector size from the main routine is %d\n",vsize); 47 48 ierr = InputTransformFFT(A,input,x);CHKERRQ(ierr); 49 50 ierr = MatMult(A,x,y);CHKERRQ(ierr); 51 ierr = VecAssemblyBegin(y);CHKERRQ(ierr); 52 ierr = VecAssemblyEnd(y);CHKERRQ(ierr); 53 ierr = VecView(y,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 54 ierr = MatMultTranspose(A,y,z);CHKERRQ(ierr); 55 ierr = VecGetSize(z,&vsize);CHKERRQ(ierr); 56 printf("The vector size of zfrom the main routine is %d\n",vsize); 57 58 ierr = OutputTransformFFT(A,z,output);CHKERRQ(ierr); 59 60 fac = 1.0/(PetscReal)N; 61 ierr = VecScale(output,fac);CHKERRQ(ierr); 62 63 ierr = VecAssemblyBegin(input);CHKERRQ(ierr); 64 ierr = VecAssemblyEnd(input);CHKERRQ(ierr); 65 ierr = VecAssemblyBegin(output);CHKERRQ(ierr); 66 ierr = VecAssemblyEnd(output);CHKERRQ(ierr); 67 68 ierr = VecView(input,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 69 ierr = VecView(output,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 70 71 ierr = VecAXPY(output,-1.0,input);CHKERRQ(ierr); 72 ierr = VecNorm(output,NORM_1,&enorm);CHKERRQ(ierr); 73 /* if (enorm > 1.e-14) { */ 74 if (!rank) { 75 ierr = PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm);CHKERRQ(ierr); 76 } 77 /* } */ 78 79 /* ierr = MatCreateVecs(A,&z,NULL);CHKERRQ(ierr); */ 80 /* printf("Vector size from ex148 %d\n",vsize); */ 81 /* ierr = PetscObjectSetName((PetscObject) x, "Real space vector");CHKERRQ(ierr); */ 82 /* ierr = PetscObjectSetName((PetscObject) y, "Frequency space vector");CHKERRQ(ierr); */ 83 /* ierr = PetscObjectSetName((PetscObject) z, "Reconstructed vector");CHKERRQ(ierr); */ 84 85 ierr = VecDestroy(&output);CHKERRQ(ierr); 86 ierr = VecDestroy(&input);CHKERRQ(ierr); 87 ierr = VecDestroy(&x);CHKERRQ(ierr); 88 ierr = VecDestroy(&y);CHKERRQ(ierr); 89 ierr = VecDestroy(&z);CHKERRQ(ierr); 90 ierr = MatDestroy(&A);CHKERRQ(ierr); 91 ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr); 92 ierr = PetscFinalize(); 93 return ierr; 94 } 95