1 static char help[] = "Test sequential USFFT interface on a 3-dof field over a uniform DMDA and compares to the result of FFTW acting on a split version of the field\n\n";
2
3 /*
4 Compiling the code:
5 This code uses the complex numbers version of PETSc and the FFTW package, so configure
6 must be run to enable these.
7
8 */
9
10 #define DOF 3
11
12 #include <petscmat.h>
13 #include <petscdm.h>
14 #include <petscdmda.h>
main(PetscInt argc,char ** args)15 PetscInt main(PetscInt argc,char **args)
16 {
17 typedef enum {RANDOM, CONSTANT, TANH, NUM_FUNCS} FuncType;
18 const char *funcNames[NUM_FUNCS] = {"random", "constant", "tanh"};
19 Mat A, AA;
20 PetscMPIInt size;
21 PetscInt N,i, stencil=1,dof=3;
22 PetscInt dim[3] = {10,10,10}, ndim = 3;
23 Vec coords,x,y,z,xx, yy, zz;
24 Vec xxsplit[DOF], yysplit[DOF], zzsplit[DOF];
25 PetscReal h[3];
26 PetscScalar s;
27 PetscRandom rdm;
28 PetscReal norm, enorm;
29 PetscInt func,ii;
30 FuncType function = TANH;
31 DM da, da1, coordsda;
32 PetscBool view_x = PETSC_FALSE, view_y = PETSC_FALSE, view_z = PETSC_FALSE;
33 PetscErrorCode ierr;
34
35 ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
36 ierr = MPI_Comm_size(PETSC_COMM_WORLD, &size);CHKERRQ(ierr);
37 if (size != 1) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_SUP, "This is a uniprocessor example only!");
38 ierr = PetscOptionsBegin(PETSC_COMM_WORLD, NULL, "USFFT Options", "ex27");CHKERRQ(ierr);
39 ierr = PetscOptionsEList("-function", "Function type", "ex27", funcNames, NUM_FUNCS, funcNames[function], &func, NULL);CHKERRQ(ierr);
40 function = (FuncType) func;
41 ierr = PetscOptionsEnd();CHKERRQ(ierr);
42 ierr = PetscOptionsGetBool(NULL,NULL,"-view_x",&view_x,NULL);CHKERRQ(ierr);
43 ierr = PetscOptionsGetBool(NULL,NULL,"-view_y",&view_y,NULL);CHKERRQ(ierr);
44 ierr = PetscOptionsGetBool(NULL,NULL,"-view_z",&view_z,NULL);CHKERRQ(ierr);
45 ierr = PetscOptionsGetIntArray(NULL,NULL,"-dim",dim,&ndim,NULL);CHKERRQ(ierr);
46
47 /* DMDA with the correct fiber dimension */
48 ierr = DMDACreate3d(PETSC_COMM_SELF,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,dim[0],dim[1],dim[2],PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,
49 dof,stencil,NULL,NULL,NULL,&da);CHKERRQ(ierr);
50 ierr = DMSetFromOptions(da);CHKERRQ(ierr);
51 ierr = DMSetUp(da);CHKERRQ(ierr);
52 /* DMDA with fiber dimension 1 for split fields */
53 ierr = DMDACreate3d(PETSC_COMM_SELF,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,dim[0],dim[1],dim[2],PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,
54 1,stencil,NULL,NULL,NULL,&da1);CHKERRQ(ierr);
55 ierr = DMSetFromOptions(da1);CHKERRQ(ierr);
56 ierr = DMSetUp(da1);CHKERRQ(ierr);
57
58 /* Coordinates */
59 ierr = DMGetCoordinateDM(da,&coordsda);
60 ierr = DMGetGlobalVector(coordsda,&coords);CHKERRQ(ierr);
61 ierr = PetscObjectSetName((PetscObject) coords,"Grid coordinates");CHKERRQ(ierr);
62 for (i = 0, N = 1; i < 3; i++) {
63 h[i] = 1.0/dim[i];
64 PetscScalar *a;
65 ierr = VecGetArray(coords, &a);CHKERRQ(ierr);
66 PetscInt j,k,n = 0;
67 for (i = 0; i < 3; ++i) {
68 for (j = 0; j < dim[i]; ++j) {
69 for (k = 0; k < 3; ++k) {
70 a[n] = j*h[i]; /* coordinate along the j-th point in the i-th dimension */
71 ++n;
72 }
73 }
74 }
75 ierr = VecRestoreArray(coords, &a);CHKERRQ(ierr);
76
77 }
78 ierr = DMSetCoordinates(da, coords);CHKERRQ(ierr);
79 ierr = VecDestroy(&coords);CHKERRQ(ierr);
80
81 /* Work vectors */
82 ierr = DMGetGlobalVector(da, &x);CHKERRQ(ierr);
83 ierr = PetscObjectSetName((PetscObject) x, "Real space vector");CHKERRQ(ierr);
84 ierr = DMGetGlobalVector(da, &xx);CHKERRQ(ierr);
85 ierr = PetscObjectSetName((PetscObject) xx, "Real space vector");CHKERRQ(ierr);
86 ierr = DMGetGlobalVector(da, &y);CHKERRQ(ierr);
87 ierr = PetscObjectSetName((PetscObject) y, "USFFT frequency space vector");CHKERRQ(ierr);
88 ierr = DMGetGlobalVector(da, &yy);CHKERRQ(ierr);
89 ierr = PetscObjectSetName((PetscObject) yy, "FFTW frequency space vector");CHKERRQ(ierr);
90 ierr = DMGetGlobalVector(da, &z);CHKERRQ(ierr);
91 ierr = PetscObjectSetName((PetscObject) z, "USFFT reconstructed vector");CHKERRQ(ierr);
92 ierr = DMGetGlobalVector(da, &zz);CHKERRQ(ierr);
93 ierr = PetscObjectSetName((PetscObject) zz, "FFTW reconstructed vector");CHKERRQ(ierr);
94 /* Split vectors for FFTW */
95 for (ii = 0; ii < 3; ++ii) {
96 ierr = DMGetGlobalVector(da1, &xxsplit[ii]);CHKERRQ(ierr);
97 ierr = PetscObjectSetName((PetscObject) xxsplit[ii], "Real space split vector");CHKERRQ(ierr);
98 ierr = DMGetGlobalVector(da1, &yysplit[ii]);CHKERRQ(ierr);
99 ierr = PetscObjectSetName((PetscObject) yysplit[ii], "FFTW frequency space split vector");CHKERRQ(ierr);
100 ierr = DMGetGlobalVector(da1, &zzsplit[ii]);CHKERRQ(ierr);
101 ierr = PetscObjectSetName((PetscObject) zzsplit[ii], "FFTW reconstructed split vector");CHKERRQ(ierr);
102 }
103
104
105 ierr = PetscPrintf(PETSC_COMM_SELF, "%3-D: USFFT on vector of ");CHKERRQ(ierr);
106 for (i = 0, N = 1; i < 3; i++) {
107 ierr = PetscPrintf(PETSC_COMM_SELF, "dim[%d] = %d ",i,dim[i]);CHKERRQ(ierr);
108 N *= dim[i];
109 }
110 ierr = PetscPrintf(PETSC_COMM_SELF, "; total size %d \n",N);CHKERRQ(ierr);
111
112
113 if (function == RANDOM) {
114 ierr = PetscRandomCreate(PETSC_COMM_SELF, &rdm);CHKERRQ(ierr);
115 ierr = PetscRandomSetFromOptions(rdm);CHKERRQ(ierr);
116 ierr = VecSetRandom(x, rdm);CHKERRQ(ierr);
117 ierr = PetscRandomDestroy(&rdm);CHKERRQ(ierr);
118 } else if (function == CONSTANT) {
119 ierr = VecSet(x, 1.0);CHKERRQ(ierr);
120 } else if (function == TANH) {
121 PetscScalar *a;
122 ierr = VecGetArray(x, &a);CHKERRQ(ierr);
123 PetscInt j,k = 0;
124 for (i = 0; i < 3; ++i) {
125 for (j = 0; j < dim[i]; ++j) {
126 a[k] = tanh((j - dim[i]/2.0)*(10.0/dim[i]));
127 ++k;
128 }
129 }
130 ierr = VecRestoreArray(x, &a);CHKERRQ(ierr);
131 }
132 if (view_x) {
133 ierr = VecView(x, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
134 }
135 ierr = VecCopy(x,xx);CHKERRQ(ierr);
136 /* Split xx */
137 ierr = VecStrideGatherAll(xx,xxsplit, INSERT_VALUES);CHKERRQ(ierr); /*YES! 'Gather' means 'split' (or maybe 'scatter'?)! */
138
139 ierr = VecNorm(x,NORM_2,&norm);CHKERRQ(ierr);
140 ierr = PetscPrintf(PETSC_COMM_SELF, "|x|_2 = %g\n",norm);CHKERRQ(ierr);
141
142 /* create USFFT object */
143 ierr = MatCreateSeqUSFFT(da,da,&A);CHKERRQ(ierr);
144 /* create FFTW object */
145 ierr = MatCreateSeqFFTW(PETSC_COMM_SELF,3,dim,&AA);CHKERRQ(ierr);
146
147 /* apply USFFT and FFTW FORWARD "preemptively", so the fftw_plans can be reused on different vectors */
148 ierr = MatMult(A,x,z);CHKERRQ(ierr);
149 for (ii = 0; ii < 3; ++ii) {
150 ierr = MatMult(AA,xxsplit[ii],zzsplit[ii]);CHKERRQ(ierr);
151 }
152 /* Now apply USFFT and FFTW forward several (3) times */
153 for (i=0; i<3; ++i) {
154 ierr = MatMult(A,x,y);CHKERRQ(ierr);
155 for (ii = 0; ii < 3; ++ii) {
156 ierr = MatMult(AA,xxsplit[ii],yysplit[ii]);CHKERRQ(ierr);
157 }
158 ierr = MatMultTranspose(A,y,z);CHKERRQ(ierr);
159 for (ii = 0; ii < 3; ++ii) {
160 ierr = MatMult(AA,yysplit[ii],zzsplit[ii]);CHKERRQ(ierr);
161 }
162 }
163 /* Unsplit yy */
164 ierr = VecStrideScatterAll(yysplit, yy, INSERT_VALUES);CHKERRQ(ierr); /*YES! 'Scatter' means 'collect' (or maybe 'gather'?)! */
165 /* Unsplit zz */
166 ierr = VecStrideScatterAll(zzsplit, zz, INSERT_VALUES);CHKERRQ(ierr); /*YES! 'Scatter' means 'collect' (or maybe 'gather'?)! */
167
168 if (view_y) {
169 ierr = PetscPrintf(PETSC_COMM_WORLD, "y = \n");CHKERRQ(ierr);
170 ierr = VecView(y, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
171 ierr = PetscPrintf(PETSC_COMM_WORLD, "yy = \n");CHKERRQ(ierr);
172 ierr = VecView(yy, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
173 }
174
175 if (view_z) {
176 ierr = PetscPrintf(PETSC_COMM_WORLD, "z = \n");CHKERRQ(ierr);
177 ierr = VecView(z, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
178 ierr = PetscPrintf(PETSC_COMM_WORLD, "zz = \n");CHKERRQ(ierr);
179 ierr = VecView(zz, PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
180 }
181
182 /* compare x and z. USFFT computes an unnormalized DFT, thus z = N*x */
183 s = 1.0/(PetscReal)N;
184 ierr = VecScale(z,s);CHKERRQ(ierr);
185 ierr = VecAXPY(x,-1.0,z);CHKERRQ(ierr);
186 ierr = VecNorm(x,NORM_1,&enorm);CHKERRQ(ierr);
187 ierr = PetscPrintf(PETSC_COMM_SELF, "|x-z| = %g\n",enorm);CHKERRQ(ierr);
188
189 /* compare xx and zz. FFTW computes an unnormalized DFT, thus zz = N*x */
190 s = 1.0/(PetscReal)N;
191 ierr = VecScale(zz,s);CHKERRQ(ierr);
192 ierr = VecAXPY(xx,-1.0,zz);CHKERRQ(ierr);
193 ierr = VecNorm(xx,NORM_1,&enorm);CHKERRQ(ierr);
194 ierr = PetscPrintf(PETSC_COMM_SELF, "|xx-zz| = %g\n",enorm);CHKERRQ(ierr);
195
196 /* compare y and yy: USFFT and FFTW results*/
197 ierr = VecNorm(y,NORM_2,&norm);CHKERRQ(ierr);
198 ierr = VecAXPY(y,-1.0,yy);CHKERRQ(ierr);
199 ierr = VecNorm(y,NORM_1,&enorm);CHKERRQ(ierr);
200 ierr = PetscPrintf(PETSC_COMM_SELF, "|y|_2 = %g\n",norm);CHKERRQ(ierr);
201 ierr = PetscPrintf(PETSC_COMM_SELF, "|y-yy| = %g\n",enorm);CHKERRQ(ierr);
202
203 /* compare z and zz: USFFT and FFTW results*/
204 ierr = VecNorm(z,NORM_2,&norm);CHKERRQ(ierr);
205 ierr = VecAXPY(z,-1.0,zz);CHKERRQ(ierr);
206 ierr = VecNorm(z,NORM_1,&enorm);CHKERRQ(ierr);
207 ierr = PetscPrintf(PETSC_COMM_SELF, "|z|_2 = %g\n",norm);CHKERRQ(ierr);
208 ierr = PetscPrintf(PETSC_COMM_SELF, "|z-zz| = %g\n",enorm);CHKERRQ(ierr);
209
210
211 /* free spaces */
212 ierr = DMRestoreGlobalVector(da,&x);CHKERRQ(ierr);
213 ierr = DMRestoreGlobalVector(da,&xx);CHKERRQ(ierr);
214 ierr = DMRestoreGlobalVector(da,&y);CHKERRQ(ierr);
215 ierr = DMRestoreGlobalVector(da,&yy);CHKERRQ(ierr);
216 ierr = DMRestoreGlobalVector(da,&z);CHKERRQ(ierr);
217 ierr = DMRestoreGlobalVector(da,&zz);CHKERRQ(ierr);
218
219 ierr = PetscFinalize();
220 return ierr;
221 }
222