1 static char help[] = "Test DMStag ghosted boundaries in 2d\n\n";
2 /* This solves a very contrived problem - the "pressure" terms are set to a constant function
3 and the "velocity" terms are just the sum of neighboring values of these, hence twice the
4 constant */
5 #include <petscdm.h>
6 #include <petscksp.h>
7 #include <petscdmstag.h>
8
9 #define PRESSURE_CONST 2.0
10
11 PetscErrorCode ApplyOperator(Mat, Vec, Vec);
12
main(int argc,char ** argv)13 int main(int argc, char **argv)
14 {
15 DM dmSol;
16 Vec sol, solRef, solRefLocal, rhs, rhsLocal;
17 Mat A;
18 KSP ksp;
19 PC pc;
20 PetscInt startx, starty, nx, ny, ex, ey, nExtrax, nExtray;
21 PetscInt iux, iuy, ip;
22 PetscInt dof0, dof1, dof2;
23 PetscScalar ***arrSol, ***arrRHS;
24
25 PetscFunctionBeginUser;
26 PetscCall(PetscInitialize(&argc, &argv, NULL, help));
27 /* Note: these defaults are chosen to suit the problem. We allow adjusting
28 them to check that things still work when you add unused extra dof */
29 dof0 = 0;
30 dof1 = 1;
31 dof2 = 1;
32 PetscCall(PetscOptionsGetInt(NULL, NULL, "-dof2", &dof2, NULL));
33 PetscCall(DMStagCreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_GHOSTED, DM_BOUNDARY_GHOSTED, 3, 3, PETSC_DECIDE, PETSC_DECIDE, dof0, dof1, dof2, DMSTAG_STENCIL_BOX, 1, NULL, NULL, &dmSol));
34 PetscCall(DMSetFromOptions(dmSol));
35 PetscCall(DMSetUp(dmSol));
36
37 /* Compute reference solution on the grid, using direct array access */
38 PetscCall(DMCreateGlobalVector(dmSol, &rhs));
39 PetscCall(DMCreateGlobalVector(dmSol, &solRef));
40 PetscCall(DMGetLocalVector(dmSol, &solRefLocal));
41 PetscCall(DMGetLocalVector(dmSol, &rhsLocal));
42 PetscCall(DMStagVecGetArray(dmSol, solRefLocal, &arrSol));
43
44 PetscCall(DMStagGetCorners(dmSol, &startx, &starty, NULL, &nx, &ny, NULL, &nExtrax, &nExtray, NULL));
45 PetscCall(DMStagVecGetArray(dmSol, rhsLocal, &arrRHS));
46
47 /* Get the correct entries for each of our variables in local element-wise storage */
48 PetscCall(DMStagGetLocationSlot(dmSol, DMSTAG_LEFT, 0, &iux));
49 PetscCall(DMStagGetLocationSlot(dmSol, DMSTAG_DOWN, 0, &iuy));
50 PetscCall(DMStagGetLocationSlot(dmSol, DMSTAG_ELEMENT, 0, &ip));
51 for (ey = starty; ey < starty + ny + nExtray; ++ey) {
52 for (ex = startx; ex < startx + nx + nExtrax; ++ex) {
53 arrSol[ey][ex][iux] = 2 * PRESSURE_CONST;
54 arrRHS[ey][ex][iux] = 0.0;
55 arrSol[ey][ex][iuy] = 2 * PRESSURE_CONST;
56 arrRHS[ey][ex][iuy] = 0.0;
57 if (ex < startx + nx && ey < starty + ny) {
58 arrSol[ey][ex][ip] = PRESSURE_CONST;
59 arrRHS[ey][ex][ip] = PRESSURE_CONST;
60 }
61 }
62 }
63 PetscCall(DMStagVecRestoreArray(dmSol, rhsLocal, &arrRHS));
64 PetscCall(DMLocalToGlobalBegin(dmSol, rhsLocal, INSERT_VALUES, rhs));
65 PetscCall(DMLocalToGlobalEnd(dmSol, rhsLocal, INSERT_VALUES, rhs));
66 PetscCall(DMStagVecRestoreArray(dmSol, solRefLocal, &arrSol));
67 PetscCall(DMLocalToGlobalBegin(dmSol, solRefLocal, INSERT_VALUES, solRef));
68 PetscCall(DMLocalToGlobalEnd(dmSol, solRefLocal, INSERT_VALUES, solRef));
69 PetscCall(DMRestoreLocalVector(dmSol, &solRefLocal));
70 PetscCall(DMRestoreLocalVector(dmSol, &rhsLocal));
71
72 /* Matrix-free Operator */
73 PetscCall(DMSetMatType(dmSol, MATSHELL));
74 PetscCall(DMCreateMatrix(dmSol, &A));
75 PetscCall(MatShellSetOperation(A, MATOP_MULT, (PetscErrorCodeFn *)ApplyOperator));
76
77 /* Solve */
78 PetscCall(DMCreateGlobalVector(dmSol, &sol));
79 PetscCall(KSPCreate(PETSC_COMM_WORLD, &ksp));
80 PetscCall(KSPSetOperators(ksp, A, A));
81 PetscCall(KSPGetPC(ksp, &pc));
82 PetscCall(PCSetType(pc, PCNONE));
83 PetscCall(KSPSetFromOptions(ksp));
84 PetscCall(KSPSolve(ksp, rhs, sol));
85
86 /* Check Solution */
87 {
88 Vec diff;
89 PetscReal normsolRef, errAbs, errRel;
90
91 PetscCall(VecDuplicate(sol, &diff));
92 PetscCall(VecCopy(sol, diff));
93 PetscCall(VecAXPY(diff, -1.0, solRef));
94 PetscCall(VecNorm(diff, NORM_2, &errAbs));
95 PetscCall(VecNorm(solRef, NORM_2, &normsolRef));
96 errRel = errAbs / normsolRef;
97 if (errAbs > 1e14 || errRel > 1e14) {
98 PetscCall(PetscPrintf(PetscObjectComm((PetscObject)dmSol), "Error (abs): %g\nError (rel): %g\n", (double)errAbs, (double)errRel));
99 PetscCall(PetscPrintf(PetscObjectComm((PetscObject)dmSol), "Non-zero error. Probable failure.\n"));
100 }
101 PetscCall(VecDestroy(&diff));
102 }
103
104 PetscCall(KSPDestroy(&ksp));
105 PetscCall(VecDestroy(&sol));
106 PetscCall(VecDestroy(&solRef));
107 PetscCall(VecDestroy(&rhs));
108 PetscCall(MatDestroy(&A));
109 PetscCall(DMDestroy(&dmSol));
110 PetscCall(PetscFinalize());
111 return 0;
112 }
113
ApplyOperator(Mat A,Vec in,Vec out)114 PetscErrorCode ApplyOperator(Mat A, Vec in, Vec out)
115 {
116 DM dm;
117 Vec inLocal, outLocal;
118 PetscScalar ***arrIn;
119 PetscScalar ***arrOut;
120 PetscInt startx, starty, nx, ny, nExtrax, nExtray, ex, ey, idxP, idxUx, idxUy, startGhostx, startGhosty, nGhostx, nGhosty;
121 PetscBool isFirstx, isFirsty, isFirstz, isLastx, isLasty, isLastz;
122
123 PetscFunctionBeginUser;
124 PetscCall(MatGetDM(A, &dm));
125 PetscCall(DMGetLocalVector(dm, &inLocal));
126 PetscCall(DMGetLocalVector(dm, &outLocal));
127 PetscCall(DMGlobalToLocalBegin(dm, in, INSERT_VALUES, inLocal));
128 PetscCall(DMGlobalToLocalEnd(dm, in, INSERT_VALUES, inLocal));
129 PetscCall(DMStagGetCorners(dm, &startx, &starty, NULL, &nx, &ny, NULL, &nExtrax, &nExtray, NULL));
130 PetscCall(DMStagGetGhostCorners(dm, &startGhostx, &startGhosty, NULL, &nGhostx, &nGhosty, NULL));
131 PetscCall(DMStagVecGetArrayRead(dm, inLocal, &arrIn));
132 PetscCall(DMStagVecGetArray(dm, outLocal, &arrOut));
133 PetscCall(DMStagGetLocationSlot(dm, DMSTAG_LEFT, 0, &idxUx));
134 PetscCall(DMStagGetLocationSlot(dm, DMSTAG_DOWN, 0, &idxUy));
135 PetscCall(DMStagGetLocationSlot(dm, DMSTAG_ELEMENT, 0, &idxP));
136 PetscCall(DMStagGetIsFirstRank(dm, &isFirstx, &isFirsty, &isFirstz));
137 PetscCall(DMStagGetIsLastRank(dm, &isLastx, &isLasty, &isLastz));
138
139 /* Set "pressures" on ghost boundaries by copying neighboring values*/
140 if (isFirstx) {
141 for (ey = starty; ey < starty + ny + nExtray; ++ey) arrIn[ey][-1][idxP] = arrIn[ey][0][idxP];
142 }
143 if (isLastx) {
144 for (ey = starty; ey < starty + ny + nExtray; ++ey) arrIn[ey][startx + nx][idxP] = arrIn[ey][startx + nx - 1][idxP];
145 }
146 if (isFirsty) {
147 for (ex = startx; ex < startx + nx + nExtrax; ++ex) arrIn[-1][ex][idxP] = arrIn[0][ex][idxP];
148 }
149 if (isLasty) {
150 for (ex = startx; ex < startx + nx + nExtrax; ++ex) arrIn[starty + ny][ex][idxP] = arrIn[starty + ny - 1][ex][idxP];
151 }
152
153 /* Apply operator on physical points */
154 for (ey = starty; ey < starty + ny + nExtray; ++ey) {
155 for (ex = startx; ex < startx + nx + nExtrax; ++ex) {
156 if (ex < startx + nx && ey < starty + ny) { /* Don't compute pressure outside domain */
157 arrOut[ey][ex][idxP] = arrIn[ey][ex][idxP];
158 }
159 arrOut[ey][ex][idxUx] = arrIn[ey][ex][idxP] + arrIn[ey][ex - 1][idxP] - arrIn[ey][ex][idxUx];
160 arrOut[ey][ex][idxUy] = arrIn[ey][ex][idxP] + arrIn[ey - 1][ex][idxP] - arrIn[ey][ex][idxUy];
161 }
162 }
163 PetscCall(DMStagVecRestoreArrayRead(dm, inLocal, &arrIn));
164 PetscCall(DMStagVecRestoreArray(dm, outLocal, &arrOut));
165 PetscCall(DMLocalToGlobalBegin(dm, outLocal, INSERT_VALUES, out));
166 PetscCall(DMLocalToGlobalEnd(dm, outLocal, INSERT_VALUES, out));
167 PetscCall(DMRestoreLocalVector(dm, &inLocal));
168 PetscCall(DMRestoreLocalVector(dm, &outLocal));
169 PetscFunctionReturn(PETSC_SUCCESS);
170 }
171
172 /*TEST
173
174 test:
175 suffix: 1
176 nsize: 1
177 output_file: output/empty.out
178
179 test:
180 suffix: 2
181 nsize: 4
182 output_file: output/empty.out
183
184 test:
185 suffix: 3
186 nsize: 1
187 args: -stag_stencil_width 2
188 output_file: output/empty.out
189
190 test:
191 suffix: 4
192 nsize: 4
193 args: -stag_grid_x 4 -stag_grid_y 5 -stag_stencil_width 2
194 output_file: output/empty.out
195
196 test:
197 suffix: 5
198 nsize: 4
199 args: -stag_dof_0 3 -stag_dof_1 2 -stag_dof_2 4 -stag_stencil_width 3 -stag_grid_x 6 -stag_grid_y 6
200 output_file: output/empty.out
201
202 TEST*/
203