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: #if defined(PETSC_USE_COMPLEX)
29: SETERRQ(PETSC_COMM_WORLD, PETSC_ERR_SUP, "This example requires real numbers. Your current scalar type is complex");
30: #endif
31: PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
32: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
34: PetscRandomCreate(PETSC_COMM_WORLD, &rnd);
36: 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);
38: /* printf("The value alloc_local is %ld from process %d\n",alloc_local,rank); */
39: printf("The value local_n0 is %ld from process %d\n", local_n0, rank);
40: /* printf("The value local_0_start is %ld from process %d\n",local_0_start,rank);*/
41: /* printf("The value local_n1 is %ld from process %d\n",local_n1,rank); */
42: /* printf("The value local_1_start is %ld from process %d\n",local_1_start,rank);*/
44: /* Allocate space for input and output arrays */
46: in1 = (double *)fftw_malloc(sizeof(double) * alloc_local * 2);
47: in2 = (double *)fftw_malloc(sizeof(double) * alloc_local * 2);
48: out = (fftw_complex *)fftw_malloc(sizeof(fftw_complex) * alloc_local);
50: N = 2 * N0 * N1 * (N2 / 2 + 1);
51: N_factor = N0 * N1 * N2;
52: n = 2 * local_n0 * N1 * (N2 / 2 + 1);
53: n1 = local_n1 * N0 * 2 * N1;
55: /* printf("The value N is %d from process %d\n",N,rank); */
56: /* printf("The value n is %d from process %d\n",n,rank); */
57: /* printf("The value n1 is %d from process %d\n",n1,rank); */
58: /* Creating data vector and accompanying array with VeccreateMPIWithArray */
59: PetscCall(VecCreateMPIWithArray(PETSC_COMM_WORLD, 1, n, N, (PetscScalar *)in1, &fin));
60: PetscCall(VecCreateMPIWithArray(PETSC_COMM_WORLD, 1, n, N, (PetscScalar *)out, &fout));
61: PetscCall(VecCreateMPIWithArray(PETSC_COMM_WORLD, 1, n, N, (PetscScalar *)in2, &fout1));
63: /* VecGetSize(fin,&size); */
64: /* printf("The size is %d\n",size); */
66: VecSet(fin, one);
67: VecSet(fout, zero);
68: VecSet(fout1, zero);
70: VecAssemblyBegin(fin);
71: VecAssemblyEnd(fin);
72: /* VecView(fin,PETSC_VIEWER_STDOUT_WORLD); */
74: VecGetArray(fin, &x_arr);
75: VecGetArray(fout1, &z_arr);
76: VecGetArray(fout, &y_arr);
78: fplan = fftw_mpi_plan_dft_r2c_3d(N0, N1, N2, (double *)x_arr, (fftw_complex *)y_arr, PETSC_COMM_WORLD, FFTW_ESTIMATE);
79: bplan = fftw_mpi_plan_dft_c2r_3d(N0, N1, N2, (fftw_complex *)y_arr, (double *)z_arr, PETSC_COMM_WORLD, FFTW_ESTIMATE);
81: fftw_execute(fplan);
82: fftw_execute(bplan);
84: VecRestoreArray(fin, &x_arr);
85: VecRestoreArray(fout1, &z_arr);
86: VecRestoreArray(fout, &y_arr);
88: /* a = 1.0/(PetscReal)N_factor; */
89: /* PetscCall(VecScale(fout1,a)); */
90: VecCreate(PETSC_COMM_WORLD, &ini);
91: VecCreate(PETSC_COMM_WORLD, &final);
92: VecSetSizes(ini, local_n0 * N1 * N2, N_factor);
93: VecSetSizes(final, local_n0 * N1 * N2, N_factor);
94: /* VecSetSizes(ini,PETSC_DECIDE,N_factor); */
95: /* VecSetSizes(final,PETSC_DECIDE,N_factor); */
96: VecSetFromOptions(ini);
97: VecSetFromOptions(final);
99: if (N2 % 2 == 0) NM = N2 + 2;
100: else NM = N2 + 1;
102: PetscCall(VecGetOwnershipRange(fin, &low, NULL));
103: printf("The local index is %d from %d\n", low, rank);
104: PetscCall(PetscMalloc1(local_n0 * N1 * N2, &indx3));
105: PetscCall(PetscMalloc1(local_n0 * N1 * N2, &indx4));
106: for (i = 0; i < local_n0; i++) {
107: for (j = 0; j < N1; j++) {
108: for (k = 0; k < N2; k++) {
109: tempindx = i * N1 * N2 + j * N2 + k;
110: tempindx1 = i * N1 * NM + j * NM + k;
112: indx3[tempindx] = local_0_start * N1 * N2 + tempindx;
113: indx4[tempindx] = low + tempindx1;
114: }
115: /* printf("index3 %d from proc %d is \n",indx3[tempindx],rank); */
116: /* printf("index4 %d from proc %d is \n",indx4[tempindx],rank); */
117: }
118: }
119: VecGetValues(fin, local_n0 * N1 * N2, indx4, x_arr);
120: VecSetValues(ini, local_n0 * N1 * N2, indx3, x_arr, INSERT_VALUES);
121: VecAssemblyBegin(ini);
122: VecAssemblyEnd(ini);
124: VecGetValues(fout1, local_n0 * N1 * N2, indx4, y_arr);
125: VecSetValues(final, local_n0 * N1 * N2, indx3, y_arr, INSERT_VALUES);
126: VecAssemblyBegin(final);
127: VecAssemblyEnd(final);
129: printf("The local index value is %ld from %d", local_n0 * N1 * N2, rank);
130: /*
131: for (i=0;i<N0;i++) {
132: for (j=0;j<N1;j++) {
133: indx=i*N1*NM+j*NM;
134: ISCreateStride(PETSC_COMM_WORLD,N2,indx,1,&indx1);
135: indx=i*N1*N2+j*N2;
136: ISCreateStride(PETSC_COMM_WORLD,N2,indx,1,&indx2);
137: VecScatterCreate(fin,indx1,ini,indx2,&vecscat);
138: VecScatterBegin(vecscat,fin,ini,INSERT_VALUES,SCATTER_FORWARD);
139: VecScatterEnd(vecscat,fin,ini,INSERT_VALUES,SCATTER_FORWARD);
140: VecScatterCreate(fout1,indx1,final,indx2,&vecscat1);
141: VecScatterBegin(vecscat1,fout1,final,INSERT_VALUES,SCATTER_FORWARD);
142: VecScatterEnd(vecscat1,fout1,final,INSERT_VALUES,SCATTER_FORWARD);
143: }
144: }
145: */
146: a = 1.0 / (PetscReal)N_factor;
147: PetscCall(VecScale(fout1, a));
148: PetscCall(VecScale(final, a));
150: VecAssemblyBegin(ini);
151: VecAssemblyEnd(ini);
153: VecAssemblyBegin(final);
154: VecAssemblyEnd(final);
156: /* VecView(final,PETSC_VIEWER_STDOUT_WORLD); */
157: PetscCall(VecAXPY(final, -1.0, ini));
158: PetscCall(VecNorm(final, NORM_1, &enorm));
159: PetscCall(PetscPrintf(PETSC_COMM_WORLD, " Error norm of |x - z| = %e\n", enorm));
160: fftw_destroy_plan(fplan);
161: fftw_destroy_plan(bplan);
162: fftw_free(in1);
163: PetscCall(VecDestroy(&fin));
164: fftw_free(out);
165: PetscCall(VecDestroy(&fout));
166: fftw_free(in2);
167: PetscCall(VecDestroy(&fout1));
169: PetscCall(PetscFinalize());
170: return 0;
171: }