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 ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRMPI(ierr); 21 ierr = MPI_Comm_rank(PETSC_COMM_WORLD, &rank);CHKERRMPI(ierr); 22 23 if (size!=1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This is a uni-processor example only"); 24 ierr = PetscRandomCreate(PETSC_COMM_SELF, &rdm);CHKERRQ(ierr); 25 ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr); 26 ierr = VecCreate(PETSC_COMM_SELF,&input);CHKERRQ(ierr); 27 ierr = VecSetSizes(input,N,N);CHKERRQ(ierr); 28 ierr = VecSetFromOptions(input);CHKERRQ(ierr); 29 ierr = VecSetRandom(input,rdm);CHKERRQ(ierr); 30 ierr = VecDuplicate(input,&output);CHKERRQ(ierr); 31 32 DIM = 5; dim[0] = N0; dim[1] = N1; dim[2] = N2; dim[3] = N3; dim[4] = N4; 33 ierr = MatCreateFFT(PETSC_COMM_SELF,DIM,dim,MATFFTW,&A);CHKERRQ(ierr); 34 ierr = MatCreateVecs(A,&x,&y);CHKERRQ(ierr); 35 ierr = MatCreateVecs(A,&z,NULL);CHKERRQ(ierr); 36 37 ierr = VecGetSize(x,&vsize);CHKERRQ(ierr); 38 printf("The vector size of input from the main routine is %d\n",vsize); 39 40 ierr = VecGetSize(z,&vsize);CHKERRQ(ierr); 41 printf("The vector size of output from the main routine is %d\n",vsize); 42 43 ierr = InputTransformFFT(A,input,x);CHKERRQ(ierr); 44 45 ierr = MatMult(A,x,y);CHKERRQ(ierr); 46 ierr = MatMultTranspose(A,y,z);CHKERRQ(ierr); 47 48 ierr = OutputTransformFFT(A,z,output);CHKERRQ(ierr); 49 fac = 1.0/(PetscReal)N; 50 ierr = VecScale(output,fac);CHKERRQ(ierr); 51 /* 52 ierr = VecAssemblyBegin(input);CHKERRQ(ierr); 53 ierr = VecAssemblyEnd(input);CHKERRQ(ierr); 54 ierr = VecAssemblyBegin(output);CHKERRQ(ierr); 55 ierr = VecAssemblyEnd(output);CHKERRQ(ierr); 56 57 ierr = VecView(input,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 58 ierr = VecView(output,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr); 59 */ 60 ierr = VecAXPY(output,-1.0,input);CHKERRQ(ierr); 61 ierr = VecNorm(output,NORM_1,&enorm);CHKERRQ(ierr); 62 /* if (enorm > 1.e-14) { */ 63 ierr = PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %e\n",enorm);CHKERRQ(ierr); 64 /* } */ 65 66 ierr = VecDestroy(&output);CHKERRQ(ierr); 67 ierr = VecDestroy(&input);CHKERRQ(ierr); 68 ierr = VecDestroy(&x);CHKERRQ(ierr); 69 ierr = VecDestroy(&y);CHKERRQ(ierr); 70 ierr = VecDestroy(&z);CHKERRQ(ierr); 71 ierr = MatDestroy(&A);CHKERRQ(ierr); 72 ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr); 73 ierr = PetscFinalize(); 74 return ierr; 75 76 } 77