xref: /libCEED/examples/petsc/src/petscutils.c (revision a9b2c5dd65841e8c467007aaab2d4e9349426d5a)
1 #include "../include/petscutils.h"
2 
3 // -----------------------------------------------------------------------------
4 // Convert PETSc MemType to libCEED MemType
5 // -----------------------------------------------------------------------------
6 CeedMemType MemTypeP2C(PetscMemType mem_type) {
7   return PetscMemTypeDevice(mem_type) ? CEED_MEM_DEVICE : CEED_MEM_HOST;
8 }
9 
10 // -----------------------------------------------------------------------------
11 // Apply 3D Kershaw mesh transformation
12 // -----------------------------------------------------------------------------
13 // Transition from a value of "a" for x=0, to a value of "b" for x=1.  Optionally
14 // smooth -- see the commented versions at the end.
15 static double step(const double a, const double b, double x) {
16   if (x <= 0) return a;
17   if (x >= 1) return b;
18   return a + (b-a) * (x);
19 }
20 
21 // 1D transformation at the right boundary
22 static double right(const double eps, const double x) {
23   return (x <= 0.5) ? (2-eps) * x : 1 + eps*(x-1);
24 }
25 
26 // 1D transformation at the left boundary
27 static double left(const double eps, const double x) {
28   return 1-right(eps,1-x);
29 }
30 
31 // Apply 3D Kershaw mesh transformation
32 // The eps parameters are in (0, 1]
33 // Uniform mesh is recovered for eps=1
34 PetscErrorCode Kershaw(DM dm_orig, PetscScalar eps) {
35   PetscErrorCode ierr;
36   Vec coord;
37   PetscInt ncoord;
38   PetscScalar *c;
39 
40   PetscFunctionBeginUser;
41   ierr = DMGetCoordinatesLocal(dm_orig, &coord); CHKERRQ(ierr);
42   ierr = VecGetLocalSize(coord, &ncoord); CHKERRQ(ierr);
43   ierr = VecGetArray(coord, &c); CHKERRQ(ierr);
44 
45   for (PetscInt i = 0; i < ncoord; i += 3) {
46     PetscScalar x = c[i], y = c[i+1], z = c[i+2];
47     PetscInt layer = x*6;
48     PetscScalar lambda = (x-layer/6.0)*6;
49     c[i] = x;
50 
51     switch (layer) {
52     case 0:
53       c[i+1] = left(eps, y);
54       c[i+2] = left(eps, z);
55       break;
56     case 1:
57     case 4:
58       c[i+1] = step(left(eps, y), right(eps, y), lambda);
59       c[i+2] = step(left(eps, z), right(eps, z), lambda);
60       break;
61     case 2:
62       c[i+1] = step(right(eps, y), left(eps, y), lambda/2);
63       c[i+2] = step(right(eps, z), left(eps, z), lambda/2);
64       break;
65     case 3:
66       c[i+1] = step(right(eps, y), left(eps, y), (1+lambda)/2);
67       c[i+2] = step(right(eps, z), left(eps, z), (1+lambda)/2);
68       break;
69     default:
70       c[i+1] = right(eps, y);
71       c[i+2] = right(eps, z);
72     }
73   }
74   ierr = VecRestoreArray(coord, &c); CHKERRQ(ierr);
75   PetscFunctionReturn(0);
76 }
77 
78 // -----------------------------------------------------------------------------
79 // Create BC label
80 // -----------------------------------------------------------------------------
81 static PetscErrorCode CreateBCLabel(DM dm, const char name[]) {
82   int ierr;
83   DMLabel label;
84 
85   PetscFunctionBeginUser;
86 
87   ierr = DMCreateLabel(dm, name); CHKERRQ(ierr);
88   ierr = DMGetLabel(dm, name, &label); CHKERRQ(ierr);
89   ierr = DMPlexMarkBoundaryFaces(dm, 1, label); CHKERRQ(ierr);
90 
91   PetscFunctionReturn(0);
92 };
93 
94 // -----------------------------------------------------------------------------
95 // This function sets up a DM for a given degree
96 // -----------------------------------------------------------------------------
97 PetscErrorCode SetupDMByDegree(DM dm, PetscInt p_degree, PetscInt q_extra,
98                                PetscInt num_comp_u,
99                                PetscInt dim, bool enforce_bc, BCFunction bc_func) {
100   PetscInt ierr, marker_ids[1] = {1};
101   PetscInt q_degree = p_degree + q_extra;
102   PetscFE fe;
103   MPI_Comm comm;
104   PetscBool      is_simplex = PETSC_TRUE;
105 
106   PetscFunctionBeginUser;
107 
108   // Check if simplex or tensor-product mesh
109   ierr = DMPlexIsSimplex(dm, &is_simplex); CHKERRQ(ierr);
110   // Setup FE
111   ierr = PetscObjectGetComm((PetscObject)dm, &comm); CHKERRQ(ierr);
112   ierr = PetscFECreateLagrange(comm, dim, num_comp_u, is_simplex, p_degree,
113                                q_degree, &fe); CHKERRQ(ierr);
114   ierr = DMAddField(dm, NULL, (PetscObject)fe); CHKERRQ(ierr);
115   ierr = DMCreateDS(dm); CHKERRQ(ierr);
116 
117   {
118     // create FE field for coordinates
119     PetscFE fe_coords;
120     PetscInt num_comp_coord;
121     ierr = DMGetCoordinateDim(dm, &num_comp_coord); CHKERRQ(ierr);
122     ierr = PetscFECreateLagrange(comm, dim, num_comp_coord, is_simplex, 1, q_degree,
123                                  &fe_coords); CHKERRQ(ierr);
124     ierr = DMProjectCoordinates(dm, fe_coords); CHKERRQ(ierr);
125     ierr = PetscFEDestroy(&fe_coords); CHKERRQ(ierr);
126   }
127 
128   // Setup DM
129   //ierr = DMCreateDS(dm); CHKERRQ(ierr);
130   if (enforce_bc) {
131     PetscBool has_label;
132     DMHasLabel(dm, "marker", &has_label);
133     if (!has_label) {CreateBCLabel(dm, "marker");}
134     DMLabel label;
135     ierr = DMGetLabel(dm, "marker", &label); CHKERRQ(ierr);
136     ierr = DMAddBoundary(dm, DM_BC_ESSENTIAL, "wall", label, 1,
137                          marker_ids, 0, 0, NULL, (void(*)(void))bc_func,
138                          NULL, NULL, NULL); CHKERRQ(ierr);
139   }
140 
141   if (!is_simplex) {
142     DM dm_coord;
143     ierr = DMGetCoordinateDM(dm, &dm_coord); CHKERRQ(ierr);
144     ierr = DMPlexSetClosurePermutationTensor(dm, PETSC_DETERMINE, NULL);
145     CHKERRQ(ierr);
146     ierr = DMPlexSetClosurePermutationTensor(dm_coord, PETSC_DETERMINE, NULL);
147     CHKERRQ(ierr);
148   }
149   ierr = PetscFEDestroy(&fe); CHKERRQ(ierr);
150 
151   PetscFunctionReturn(0);
152 };
153 
154 // -----------------------------------------------------------------------------
155 // Get CEED restriction data from DMPlex
156 // -----------------------------------------------------------------------------
157 PetscErrorCode CreateRestrictionFromPlex(Ceed ceed, DM dm, CeedInt height,
158     DMLabel domain_label, CeedInt value, CeedElemRestriction *elem_restr) {
159   PetscInt num_elem, elem_size, num_dof, num_comp, *elem_restr_offsets;
160   PetscErrorCode ierr;
161 
162   PetscFunctionBeginUser;
163 
164   ierr = DMPlexGetLocalOffsets(dm, domain_label, value, height, 0, &num_elem,
165                                &elem_size, &num_comp, &num_dof, &elem_restr_offsets);
166   CHKERRQ(ierr);
167 
168   CeedElemRestrictionCreate(ceed, num_elem, elem_size, num_comp,
169                             1, num_dof, CEED_MEM_HOST, CEED_COPY_VALUES,
170                             elem_restr_offsets, elem_restr);
171   ierr = PetscFree(elem_restr_offsets); CHKERRQ(ierr);
172 
173   PetscFunctionReturn(0);
174 };
175 
176 // -----------------------------------------------------------------------------
177 // Utility function - convert from DMPolytopeType to CeedElemTopology
178 // -----------------------------------------------------------------------------
179 CeedElemTopology ElemTopologyP2C(DMPolytopeType cell_type) {
180   switch (cell_type) {
181   case DM_POLYTOPE_TRIANGLE:      return CEED_TOPOLOGY_TRIANGLE;
182   case DM_POLYTOPE_QUADRILATERAL: return CEED_TOPOLOGY_QUAD;
183   case DM_POLYTOPE_TETRAHEDRON:   return CEED_TOPOLOGY_TET;
184   case DM_POLYTOPE_HEXAHEDRON:    return CEED_TOPOLOGY_HEX;
185   default:                        return 0;
186   }
187 }
188 
189 // -----------------------------------------------------------------------------
190 // Get CEED Basis from DMPlex
191 // -----------------------------------------------------------------------------
192 PetscErrorCode CreateBasisFromPlex(Ceed ceed, DM dm, DMLabel domain_label,
193                                    CeedInt label_value, CeedInt height,
194                                    CeedInt dm_field, CeedBasis *basis) {
195   PetscErrorCode   ierr;
196   PetscDS          ds;
197   PetscFE          fe;
198   PetscQuadrature  quadrature;
199   PetscBool        is_simplex = PETSC_TRUE;
200   PetscInt         dim, ds_field = -1, num_comp, P, Q;
201 
202   PetscFunctionBeginUser;
203 
204   // Get basis information
205   {
206     IS             field_is;
207     const PetscInt *fields;
208     PetscInt       num_fields;
209 
210     ierr = DMGetRegionDS(dm, domain_label, &field_is, &ds); CHKERRQ(ierr);
211     // Translate dm_field to ds_field
212     ierr = ISGetIndices(field_is, &fields); CHKERRQ(ierr);
213     ierr = ISGetSize(field_is, &num_fields); CHKERRQ(ierr);
214     for (PetscInt i = 0; i < num_fields; i++) {
215       if (dm_field == fields[i]) {
216         ds_field = i;
217         break;
218       }
219     }
220     ierr = ISRestoreIndices(field_is, &fields); CHKERRQ(ierr);
221   }
222   if (ds_field == -1) {
223     // LCOV_EXCL_START
224     SETERRQ(PetscObjectComm((PetscObject) dm), PETSC_ERR_SUP,
225             "Could not find dm_field %D in DS", dm_field);
226     // LCOV_EXCL_STOP
227   }
228 
229   // Get element information
230   {
231     PetscDualSpace dual_space;
232     PetscInt       num_dual_basis_vectors;
233 
234     ierr = PetscDSGetDiscretization(ds, ds_field, (PetscObject *)&fe);
235     CHKERRQ(ierr);
236     ierr = PetscFEGetHeightSubspace(fe, height, &fe); CHKERRQ(ierr);
237     ierr = PetscFEGetSpatialDimension(fe, &dim); CHKERRQ(ierr);
238     ierr = PetscFEGetNumComponents(fe, &num_comp); CHKERRQ(ierr);
239     ierr = PetscFEGetDualSpace(fe, &dual_space); CHKERRQ(ierr);
240     ierr = PetscDualSpaceGetDimension(dual_space, &num_dual_basis_vectors);
241     CHKERRQ(ierr);
242     P = num_dual_basis_vectors / num_comp;
243     ierr = PetscFEGetQuadrature(fe, &quadrature); CHKERRQ(ierr);
244     ierr = PetscQuadratureGetData(quadrature, NULL, NULL, &Q, NULL, NULL);
245     CHKERRQ(ierr);
246   }
247 
248   // Check if simplex or tensor-product mesh
249   ierr = DMPlexIsSimplex(dm, &is_simplex); CHKERRQ(ierr);
250   // Build libCEED basis
251   if (is_simplex) {
252     PetscInt          num_derivatives = 1, first_point;
253     PetscInt          ids[1] = {label_value};
254     PetscTabulation   basis_tabulation;
255     const PetscScalar *q_points, *q_weights;
256     DMLabel           depth_label;
257     DMPolytopeType    cell_type;
258     CeedElemTopology  elem_topo;
259     PetscScalar       *interp, *grad;
260 
261     // Use depth label if no domain label present
262     if (!domain_label) {
263       PetscInt depth;
264 
265       ierr = DMPlexGetDepth(dm, &depth); CHKERRQ(ierr);
266       ierr = DMPlexGetDepthLabel(dm, &depth_label); CHKERRQ(ierr);
267       ids[0] = depth - height;
268     }
269     // Get cell interp, grad, and quadrature data
270     ierr = PetscFEGetCellTabulation(fe, num_derivatives, &basis_tabulation);
271     CHKERRQ(ierr);
272     ierr = PetscQuadratureGetData(quadrature, NULL, NULL, NULL, &q_points,
273                                   &q_weights); CHKERRQ(ierr);
274     ierr = DMGetFirstLabeledPoint(dm, dm, domain_label ? domain_label : depth_label,
275                                   1, ids, height, &first_point, NULL);
276     CHKERRQ(ierr);
277     ierr = DMPlexGetCellType(dm, first_point, &cell_type); CHKERRQ(ierr);
278     elem_topo = ElemTopologyP2C(cell_type);
279     if (!elem_topo) SETERRQ(PetscObjectComm((PetscObject) dm), PETSC_ERR_SUP,
280                               "DMPlex topology not supported");
281     // Convert to libCEED orientation
282     ierr = PetscCalloc(P * Q * sizeof(PetscScalar), &interp); CHKERRQ(ierr);
283     ierr = PetscCalloc(P * Q * dim * sizeof(PetscScalar), &grad); CHKERRQ(ierr);
284     const CeedInt c = 0;
285     for (CeedInt q = 0; q < Q; q++) {
286       for (CeedInt p = 0; p < P; p++) {
287         interp[q*P + p] = basis_tabulation->T[0][(q*P + p)*num_comp*num_comp + c];
288         for (CeedInt d = 0; d < dim; d++) {
289           grad[(d*Q + q)*P + p] = basis_tabulation->T[1][((q*P + p)*num_comp*num_comp + c)
290                                   *dim + d];
291         }
292       }
293     }
294     // Finaly, create libCEED basis
295     ierr = CeedBasisCreateH1(ceed, elem_topo, num_comp, P, Q, interp, grad,
296                              q_points, q_weights, basis);
297     CHKERRQ(ierr);
298     ierr = PetscFree(interp); CHKERRQ(ierr);
299     ierr = PetscFree(grad); CHKERRQ(ierr);
300   } else {
301     CeedInt P_1d = (CeedInt) round(pow(P, 1.0 / dim));
302     CeedInt Q_1d = (CeedInt) round(pow(Q, 1.0 / dim));
303 
304     ierr = CeedBasisCreateTensorH1Lagrange(ceed, dim, num_comp, P_1d, Q_1d,
305                                            CEED_GAUSS, basis);
306     CHKERRQ(ierr);
307   }
308 
309   PetscFunctionReturn(0);
310 };
311 
312 // -----------------------------------------------------------------------------
313 // Utilities
314 // -----------------------------------------------------------------------------
315 
316 // Utility function, compute three factors of an integer
317 static void Split3(PetscInt size, PetscInt m[3], bool reverse) {
318   for (PetscInt d=0, size_left=size; d<3; d++) {
319     PetscInt try = (PetscInt)PetscCeilReal(PetscPowReal(size_left, 1./(3 - d)));
320     while (try * (size_left / try) != size_left) try++;
321     m[reverse ? 2-d : d] = try;
322     size_left /= try;
323   }
324 }
325 
326 static int Max3(const PetscInt a[3]) {
327   return PetscMax(a[0], PetscMax(a[1], a[2]));
328 }
329 
330 static int Min3(const PetscInt a[3]) {
331   return PetscMin(a[0], PetscMin(a[1], a[2]));
332 }
333 
334 // -----------------------------------------------------------------------------
335 // Create distribute dm
336 // -----------------------------------------------------------------------------
337 PetscErrorCode CreateDistributedDM(RunParams rp, DM *dm) {
338   PetscErrorCode   ierr;
339 
340   PetscFunctionBeginUser;
341   // Setup DM
342   if (rp->read_mesh) {
343     ierr = DMPlexCreateFromFile(PETSC_COMM_WORLD, rp->filename, NULL, PETSC_TRUE,
344                                 dm);
345     CHKERRQ(ierr);
346   } else {
347     if (rp->user_l_nodes) {
348       // Find a nicely composite number of elements no less than global nodes
349       PetscMPIInt size;
350       ierr = MPI_Comm_size(rp->comm, &size); CHKERRQ(ierr);
351       for (PetscInt g_elem =
352              PetscMax(1, size * rp->local_nodes / PetscPowInt(rp->degree, rp->dim));
353            ;
354            g_elem++) {
355         Split3(g_elem, rp->mesh_elem, true);
356         if (Max3(rp->mesh_elem) / Min3(rp->mesh_elem) <= 2) break;
357       }
358     }
359     ierr = DMPlexCreateBoxMesh(PETSC_COMM_WORLD, rp->dim, rp->simplex,
360                                rp->mesh_elem,
361                                NULL, NULL, NULL, PETSC_TRUE, dm); CHKERRQ(ierr);
362   }
363 
364   ierr = DMSetFromOptions(*dm); CHKERRQ(ierr);
365   ierr = DMViewFromOptions(*dm, NULL, "-dm_view"); CHKERRQ(ierr);
366 
367   PetscFunctionReturn(0);
368 }
369 
370 // -----------------------------------------------------------------------------
371