1 static char help[] = "Test sequential FFTW interface \n\n"; 2 3 /* 4 Compiling the code: 5 This code uses the complex numbers version of PETSc, so configure 6 must be run to enable this 7 8 */ 9 10 #include <petscmat.h> 11 int main(int argc,char **args) 12 { 13 typedef enum {RANDOM, CONSTANT, TANH, NUM_FUNCS} FuncType; 14 const char *funcNames[NUM_FUNCS] = {"random", "constant", "tanh"}; 15 Mat A; 16 PetscMPIInt size; 17 PetscInt n = 10,N,ndim=4,dim[4],DIM,i; 18 Vec x,y,z; 19 PetscScalar s; 20 PetscRandom rdm; 21 PetscReal enorm, tol = PETSC_SMALL; 22 PetscInt func; 23 FuncType function = RANDOM; 24 PetscBool view = PETSC_FALSE; 25 PetscErrorCode ierr; 26 27 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr; 28 CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size)); 29 PetscCheckFalse(size != 1,PETSC_COMM_WORLD,PETSC_ERR_SUP, "This is a uniprocessor example only!"); 30 ierr = PetscOptionsBegin(PETSC_COMM_WORLD, NULL, "FFTW Options", "ex112");CHKERRQ(ierr); 31 CHKERRQ(PetscOptionsEList("-function", "Function type", "ex112", funcNames, NUM_FUNCS, funcNames[function], &func, NULL)); 32 CHKERRQ(PetscOptionsBool("-vec_view_draw", "View the functions", "ex112", view, &view, NULL)); 33 function = (FuncType) func; 34 ierr = PetscOptionsEnd();CHKERRQ(ierr); 35 36 for (DIM = 0; DIM < ndim; DIM++) { 37 dim[DIM] = n; /* size of transformation in DIM-dimension */ 38 } 39 CHKERRQ(PetscRandomCreate(PETSC_COMM_SELF, &rdm)); 40 CHKERRQ(PetscRandomSetFromOptions(rdm)); 41 42 for (DIM = 1; DIM < 5; DIM++) { 43 for (i = 0, N = 1; i < DIM; i++) N *= dim[i]; 44 CHKERRQ(PetscPrintf(PETSC_COMM_SELF, "\n %d-D: FFTW on vector of size %d \n",DIM,N)); 45 46 /* create FFTW object */ 47 CHKERRQ(MatCreateFFT(PETSC_COMM_SELF,DIM,dim,MATFFTW,&A)); 48 49 /* create vectors of length N=n^DIM */ 50 CHKERRQ(MatCreateVecs(A,&x,&y)); 51 CHKERRQ(MatCreateVecs(A,&z,NULL)); 52 CHKERRQ(PetscObjectSetName((PetscObject) x, "Real space vector")); 53 CHKERRQ(PetscObjectSetName((PetscObject) y, "Frequency space vector")); 54 CHKERRQ(PetscObjectSetName((PetscObject) z, "Reconstructed vector")); 55 56 /* set values of space vector x */ 57 if (function == RANDOM) { 58 CHKERRQ(VecSetRandom(x, rdm)); 59 } else if (function == CONSTANT) { 60 CHKERRQ(VecSet(x, 1.0)); 61 } else if (function == TANH) { 62 PetscScalar *a; 63 CHKERRQ(VecGetArray(x, &a)); 64 for (i = 0; i < N; ++i) { 65 a[i] = tanh((i - N/2.0)*(10.0/N)); 66 } 67 CHKERRQ(VecRestoreArray(x, &a)); 68 } 69 if (view) CHKERRQ(VecView(x, PETSC_VIEWER_DRAW_WORLD)); 70 71 /* apply FFTW_FORWARD and FFTW_BACKWARD several times on same x, y, and z */ 72 for (i=0; i<3; i++) { 73 CHKERRQ(MatMult(A,x,y)); 74 if (view && i == 0) CHKERRQ(VecView(y, PETSC_VIEWER_DRAW_WORLD)); 75 CHKERRQ(MatMultTranspose(A,y,z)); 76 77 /* compare x and z. FFTW computes an unnormalized DFT, thus z = N*x */ 78 s = 1.0/(PetscReal)N; 79 CHKERRQ(VecScale(z,s)); 80 if (view && i == 0) CHKERRQ(VecView(z, PETSC_VIEWER_DRAW_WORLD)); 81 CHKERRQ(VecAXPY(z,-1.0,x)); 82 CHKERRQ(VecNorm(z,NORM_1,&enorm)); 83 if (enorm > tol) { 84 CHKERRQ(PetscPrintf(PETSC_COMM_SELF," Error norm of |x - z| %g\n",(double)enorm)); 85 } 86 } 87 88 /* apply FFTW_FORWARD and FFTW_BACKWARD several times on different x */ 89 for (i=0; i<3; i++) { 90 CHKERRQ(VecDestroy(&x)); 91 CHKERRQ(VecCreateSeq(PETSC_COMM_SELF,N,&x)); 92 CHKERRQ(VecSetRandom(x, rdm)); 93 94 CHKERRQ(MatMult(A,x,y)); 95 CHKERRQ(MatMultTranspose(A,y,z)); 96 97 /* compare x and z. FFTW computes an unnormalized DFT, thus z = N*x */ 98 s = 1.0/(PetscReal)N; 99 CHKERRQ(VecScale(z,s)); 100 if (view && i == 0) CHKERRQ(VecView(z, PETSC_VIEWER_DRAW_WORLD)); 101 CHKERRQ(VecAXPY(z,-1.0,x)); 102 CHKERRQ(VecNorm(z,NORM_1,&enorm)); 103 if (enorm > tol) { 104 CHKERRQ(PetscPrintf(PETSC_COMM_SELF," Error norm of new |x - z| %g\n",(double)enorm)); 105 } 106 } 107 108 /* free spaces */ 109 CHKERRQ(VecDestroy(&x)); 110 CHKERRQ(VecDestroy(&y)); 111 CHKERRQ(VecDestroy(&z)); 112 CHKERRQ(MatDestroy(&A)); 113 } 114 CHKERRQ(PetscRandomDestroy(&rdm)); 115 ierr = PetscFinalize(); 116 return ierr; 117 } 118 119 /*TEST 120 121 build: 122 requires: fftw complex 123 124 test: 125 args: -mat_fftw_plannerflags FFTW_ESTIMATE 126 output_file: output/ex112.out 127 128 test: 129 suffix: 2 130 args: -mat_fftw_plannerflags FFTW_MEASURE 131 output_file: output/ex112.out 132 requires: !defined(PETSC_USE_CXXCOMPLEX) 133 134 test: 135 suffix: 3 136 args: -mat_fftw_plannerflags FFTW_PATIENT 137 output_file: output/ex112.out 138 139 test: 140 suffix: 4 141 args: -mat_fftw_plannerflags FFTW_EXHAUSTIVE 142 output_file: output/ex112.out 143 144 TEST*/ 145