Actual source code: ex146.c
1: /* This program illustrates use of parallel real FFT*/
2: static char help[] = "This program illustrates the use of parallel real 3D fftw (without PETSc interface)";
3: #include <petscmat.h>
4: #include <fftw3.h>
5: #include <fftw3-mpi.h>
7: int main(int argc, char **args)
8: {
9: ptrdiff_t N0 = 256, N1 = 256, N2 = 256, N3 = 2, dim[4];
10: fftw_plan bplan, fplan;
11: fftw_complex *out;
12: double *in1, *in2;
13: ptrdiff_t alloc_local, local_n0, local_0_start;
14: ptrdiff_t local_n1, local_1_start;
15: PetscInt i, j, indx, n1;
16: PetscInt size, rank, n, N, *in, N_factor, NM;
17: PetscScalar *data_fin, value1, one = 1.57, zero = 0.0;
18: PetscScalar a, *x_arr, *y_arr, *z_arr, enorm;
19: Vec fin, fout, fout1, ini, final;
20: PetscRandom rnd;
21: VecScatter vecscat, vecscat1;
22: IS indx1, indx2;
23: PetscInt *indx3, k, l, *indx4;
24: PetscInt low, tempindx, tempindx1;
26: PetscFunctionBeginUser;
27: PetscCall(PetscInitialize(&argc, &args, NULL, help));
28: PetscCheck(!PetscDefined(USE_COMPLEX), PETSC_COMM_WORLD, PETSC_ERR_SUP, "This example requires real numbers. Your current scalar type is complex");
29: PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
30: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
32: PetscRandomCreate(PETSC_COMM_WORLD, &rnd);
34: alloc_local = fftw_mpi_local_size_3d_transposed(N0, N1, N2 / 2 + 1, PETSC_COMM_WORLD, &local_n0, &local_0_start, &local_n1, &local_1_start);
36: /* printf("The value alloc_local is %ld from process %d\n",alloc_local,rank); */
37: printf("The value local_n0 is %ld from process %d\n", local_n0, rank);
38: /* printf("The value local_0_start is %ld from process %d\n",local_0_start,rank);*/
39: /* printf("The value local_n1 is %ld from process %d\n",local_n1,rank); */
40: /* printf("The value local_1_start is %ld from process %d\n",local_1_start,rank);*/
42: /* Allocate space for input and output arrays */
44: in1 = (double *)fftw_malloc(sizeof(double) * alloc_local * 2);
45: in2 = (double *)fftw_malloc(sizeof(double) * alloc_local * 2);
46: out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * alloc_local);
48: N = 2 * N0 * N1 * (N2 / 2 + 1);
49: N_factor = N0 * N1 * N2;
50: n = 2 * local_n0 * N1 * (N2 / 2 + 1);
51: n1 = local_n1 * N0 * 2 * N1;
53: /* printf("The value N is %d from process %d\n",N,rank); */
54: /* printf("The value n is %d from process %d\n",n,rank); */
55: /* printf("The value n1 is %d from process %d\n",n1,rank); */
56: /* Creating data vector and accompanying array with VeccreateMPIWithArray */
57: PetscCall(VecCreateMPIWithArray(PETSC_COMM_WORLD, 1, n, N, (PetscScalar *)in1, &fin));
58: PetscCall(VecCreateMPIWithArray(PETSC_COMM_WORLD, 1, n, N, (PetscScalar *)out, &fout));
59: PetscCall(VecCreateMPIWithArray(PETSC_COMM_WORLD, 1, n, N, (PetscScalar *)in2, &fout1));
61: /* VecGetSize(fin,&size); */
62: /* printf("The size is %d\n",size); */
64: VecSet(fin, one);
65: VecSet(fout, zero);
66: VecSet(fout1, zero);
68: VecAssemblyBegin(fin);
69: VecAssemblyEnd(fin);
70: /* VecView(fin,PETSC_VIEWER_STDOUT_WORLD); */
72: VecGetArray(fin, &x_arr);
73: VecGetArray(fout1, &z_arr);
74: VecGetArray(fout, &y_arr);
76: fplan = fftw_mpi_plan_dft_r2c_3d(N0, N1, N2, (double *)x_arr, (fftw_complex *)y_arr, PETSC_COMM_WORLD, FFTW_ESTIMATE);
77: bplan = fftw_mpi_plan_dft_c2r_3d(N0, N1, N2, (fftw_complex *)y_arr, (double *)z_arr, PETSC_COMM_WORLD, FFTW_ESTIMATE);
79: fftw_execute(fplan);
80: fftw_execute(bplan);
82: VecRestoreArray(fin, &x_arr);
83: VecRestoreArray(fout1, &z_arr);
84: VecRestoreArray(fout, &y_arr);
86: /* a = 1.0/(PetscReal)N_factor; */
87: /* PetscCall(VecScale(fout1,a)); */
88: VecCreate(PETSC_COMM_WORLD, &ini);
89: VecCreate(PETSC_COMM_WORLD, &final);
90: VecSetSizes(ini, local_n0 * N1 * N2, N_factor);
91: VecSetSizes(final, local_n0 * N1 * N2, N_factor);
92: /* VecSetSizes(ini,PETSC_DECIDE,N_factor); */
93: /* VecSetSizes(final,PETSC_DECIDE,N_factor); */
94: VecSetFromOptions(ini);
95: VecSetFromOptions(final);
97: if (N2 % 2 == 0) NM = N2 + 2;
98: else NM = N2 + 1;
100: PetscCall(VecGetOwnershipRange(fin, &low, NULL));
101: printf("The local index is %d from %d\n", low, rank);
102: PetscCall(PetscMalloc1(local_n0 * N1 * N2, &indx3));
103: PetscCall(PetscMalloc1(local_n0 * N1 * N2, &indx4));
104: for (i = 0; i < local_n0; i++) {
105: for (j = 0; j < N1; j++) {
106: for (k = 0; k < N2; k++) {
107: tempindx = i * N1 * N2 + j * N2 + k;
108: tempindx1 = i * N1 * NM + j * NM + k;
110: indx3[tempindx] = local_0_start * N1 * N2 + tempindx;
111: indx4[tempindx] = low + tempindx1;
112: }
113: /* printf("index3 %d from proc %d is \n",indx3[tempindx],rank); */
114: /* printf("index4 %d from proc %d is \n",indx4[tempindx],rank); */
115: }
116: }
117: VecGetValues(fin, local_n0 * N1 * N2, indx4, x_arr);
118: VecSetValues(ini, local_n0 * N1 * N2, indx3, x_arr, INSERT_VALUES);
119: VecAssemblyBegin(ini);
120: VecAssemblyEnd(ini);
122: VecGetValues(fout1, local_n0 * N1 * N2, indx4, y_arr);
123: VecSetValues(final, local_n0 * N1 * N2, indx3, y_arr, INSERT_VALUES);
124: VecAssemblyBegin(final);
125: VecAssemblyEnd(final);
127: printf("The local index value is %ld from %d", local_n0 * N1 * N2, rank);
128: /*
129: for (i=0;i<N0;i++) {
130: for (j=0;j<N1;j++) {
131: indx=i*N1*NM+j*NM;
132: ISCreateStride(PETSC_COMM_WORLD,N2,indx,1,&indx1);
133: indx=i*N1*N2+j*N2;
134: ISCreateStride(PETSC_COMM_WORLD,N2,indx,1,&indx2);
135: VecScatterCreate(fin,indx1,ini,indx2,&vecscat);
136: VecScatterBegin(vecscat,fin,ini,INSERT_VALUES,SCATTER_FORWARD);
137: VecScatterEnd(vecscat,fin,ini,INSERT_VALUES,SCATTER_FORWARD);
138: VecScatterCreate(fout1,indx1,final,indx2,&vecscat1);
139: VecScatterBegin(vecscat1,fout1,final,INSERT_VALUES,SCATTER_FORWARD);
140: VecScatterEnd(vecscat1,fout1,final,INSERT_VALUES,SCATTER_FORWARD);
141: }
142: }
143: */
144: a = 1.0 / (PetscReal)N_factor;
145: PetscCall(VecScale(fout1, a));
146: PetscCall(VecScale(final, a));
148: VecAssemblyBegin(ini);
149: VecAssemblyEnd(ini);
151: VecAssemblyBegin(final);
152: VecAssemblyEnd(final);
154: /* VecView(final,PETSC_VIEWER_STDOUT_WORLD); */
155: PetscCall(VecAXPY(final, -1.0, ini));
156: PetscCall(VecNorm(final, NORM_1, &enorm));
157: PetscCall(PetscPrintf(PETSC_COMM_WORLD, " Error norm of |x - z| = %e\n", enorm));
158: fftw_destroy_plan(fplan);
159: fftw_destroy_plan(bplan);
160: fftw_free(in1);
161: PetscCall(VecDestroy(&fin));
162: fftw_free(out);
163: PetscCall(VecDestroy(&fout));
164: fftw_free(in2);
165: PetscCall(VecDestroy(&fout1));
167: PetscCall(PetscFinalize());
168: return 0;
169: }