xref: /petsc/src/dm/impls/plex/plexceed.c (revision f2b10e4d2a0ebe582136d1b30ebc17292eb8f275)
1 #include <petsc/private/dmpleximpl.h>           /*I      "petscdmplex.h"          I*/
2 
3 /*@C
4   DMPlexGetLocalOffsets - Allocate and populate array of local offsets.
5 
6   Input Parameters:
7   dm - The DMPlex object
8   domain_label - label for DMPlex domain, or NULL for whole domain
9   label_value - Stratum value
10   height - Height of target cells in DMPlex topology
11   dm_field - Index of DMPlex field
12 
13   Output Parameters:
14   num_cells - Number of local cells
15   cell_size - Size of each cell, given by cell_size * num_comp = num_dof
16   num_comp - Number of components per dof
17   l_size - Size of local vector
18   offsets - Allocated offsets array for cells
19 
20   Notes: Allocate and populate array of shape [num_cells, cell_size] defining offsets for each value (cell, node) for local vector of the DMPlex field. All offsets are in the range [0, l_size - 1]. Caller is responsible for freeing the offsets array using PetscFree().
21 
22   Level: developer
23 
24 .seealso: DMPlexGetClosureIndices(), DMPlexSetClosurePermutationTensor(), DMPlexGetCeedRestriction()
25 @*/
26 PetscErrorCode DMPlexGetLocalOffsets(DM dm, DMLabel domain_label, PetscInt label_value, PetscInt height, PetscInt dm_field, PetscInt *num_cells, PetscInt *cell_size, PetscInt *num_comp, PetscInt *l_size, PetscInt **offsets)
27 {
28   PetscErrorCode ierr;
29 
30   PetscFunctionBeginUser;
31   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
32   PetscDS      ds = NULL;
33   PetscFE      fe;
34   PetscSection section;
35   PetscInt     dim;
36   PetscInt    *restr_indices;
37   const PetscInt *iter_indices;
38   IS           iter_is;
39 
40   ierr = DMGetLocalSection(dm, &section);CHKERRQ(ierr);
41   ierr = DMGetDimension(dm, &dim);CHKERRQ(ierr);
42   if (domain_label) {
43     ierr = DMGetFirstLabelEntry_Internal(dm, dm, domain_label, 1, &label_value, dim, NULL, &ds);CHKERRQ(ierr);
44   }
45 
46   // Translate dm_field to ds_field
47   PetscInt ds_field = -1;
48   for (PetscInt i=0; i<dm->Nds; i++) {
49     if (!domain_label || domain_label == dm->probs[i].label) {
50       ds = dm->probs[i].ds;
51     }
52     if (ds == dm->probs[i].ds) {
53       const PetscInt *arr;
54       PetscInt nf;
55       IS is = dm->probs[i].fields;
56       ierr = ISGetIndices(is, &arr);CHKERRQ(ierr);
57       ierr = ISGetSize(is, &nf);CHKERRQ(ierr);
58       for (PetscInt j=0; j<nf; j++) {
59         if (dm_field == arr[j]) {
60           ds_field = j;
61           break;
62         }
63       }
64       ierr = ISRestoreIndices(is, &arr);CHKERRQ(ierr);
65     }
66   }
67   if (ds_field == -1) SETERRQ1(PetscObjectComm((PetscObject) dm), PETSC_ERR_SUP, "Could not find dm_field %D in DS", dm_field);
68 
69   {
70     PetscInt depth;
71     DMLabel depth_label;
72     IS depth_is;
73     ierr = DMPlexGetDepth(dm, &depth);CHKERRQ(ierr);
74     ierr = DMPlexGetDepthLabel(dm, &depth_label);CHKERRQ(ierr);
75     ierr = DMLabelGetStratumIS(depth_label, depth - height, &depth_is);CHKERRQ(ierr);
76     if (domain_label) {
77       IS domain_is;
78       ierr = DMLabelGetStratumIS(domain_label, label_value, &domain_is);CHKERRQ(ierr);
79       if (domain_is) { // domainIS is non-empty
80         ierr = ISIntersect(depth_is, domain_is, &iter_is);CHKERRQ(ierr);
81         ierr = ISDestroy(&domain_is);CHKERRQ(ierr);
82       } else { // domainIS is NULL (empty)
83         iter_is = NULL;
84       }
85       ierr = ISDestroy(&depth_is);CHKERRQ(ierr);
86     } else {
87       iter_is = depth_is;
88     }
89     if (iter_is) {
90       ierr = ISGetLocalSize(iter_is, num_cells);CHKERRQ(ierr);
91       ierr = ISGetIndices(iter_is, &iter_indices);CHKERRQ(ierr);
92     } else {
93       *num_cells = 0;
94       iter_indices = NULL;
95     }
96   }
97 
98   {
99     PetscDualSpace dual_space;
100     PetscInt num_dual_basis_vectors;
101     ierr = PetscDSGetDiscretization(ds, ds_field, (PetscObject*)&fe);CHKERRQ(ierr);
102     ierr = PetscFEGetHeightSubspace(fe, height, &fe);CHKERRQ(ierr);
103     ierr = PetscFEGetDualSpace(fe, &dual_space);CHKERRQ(ierr);
104     ierr = PetscDualSpaceGetDimension(dual_space, &num_dual_basis_vectors);CHKERRQ(ierr);
105     ierr = PetscDualSpaceGetNumComponents(dual_space, num_comp);CHKERRQ(ierr);
106     if (num_dual_basis_vectors % *num_comp != 0) SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for number of dual basis vectors %D not divisible by %D components", num_dual_basis_vectors, *num_comp);
107     *cell_size = num_dual_basis_vectors / *num_comp;
108   }
109   PetscInt restr_size = (*num_cells)*(*cell_size);
110   ierr = PetscMalloc1(restr_size, &restr_indices);CHKERRQ(ierr);
111   PetscInt cell_offset = 0;
112 
113   PetscInt P = (PetscInt) pow(*cell_size, 1.0 / (dim - height));
114   for (PetscInt p = 0; p < *num_cells; p++) {
115     PetscBool flip = PETSC_FALSE;
116     PetscInt c = iter_indices[p];
117     PetscInt num_indices, *indices;
118     PetscInt field_offsets[17]; // max number of fields plus 1
119     ierr = DMPlexGetClosureIndices(dm, section, section, c, PETSC_TRUE, &num_indices, &indices, field_offsets, NULL);CHKERRQ(ierr);
120     if (height > 0) {
121       PetscInt num_cells_support, num_faces, start = -1;
122       const PetscInt *orients, *faces, *cells;
123       ierr = DMPlexGetSupport(dm, c, &cells);CHKERRQ(ierr);
124       ierr = DMPlexGetSupportSize(dm, c, &num_cells_support);CHKERRQ(ierr);
125       if (num_cells_support != 1) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Expected one cell in support of exterior face, but got %D cells", num_cells_support);
126       ierr = DMPlexGetCone(dm, cells[0], &faces);CHKERRQ(ierr);
127       ierr = DMPlexGetConeSize(dm, cells[0], &num_faces);CHKERRQ(ierr);
128       for (PetscInt i=0; i<num_faces; i++) {if (faces[i] == c) start = i;}
129       if (start < 0) SETERRQ1(PETSC_COMM_SELF, PETSC_ERR_ARG_CORRUPT, "Could not find face %D in cone of its support", c);
130       ierr = DMPlexGetConeOrientation(dm, cells[0], &orients);CHKERRQ(ierr);
131       if (orients[start] < 0) flip = PETSC_TRUE;
132     }
133 
134     for (PetscInt i = 0; i < *cell_size; i++) {
135       PetscInt ii = i;
136       if (flip) {
137         if (*cell_size == P) ii = *cell_size - 1 - i;
138         else if (*cell_size == P*P) {
139           PetscInt row = i / P, col = i % P;
140           ii = row + col * P;
141         } else SETERRQ2(PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for flipping point with cell size %D != P (%D) or P^2", *cell_size, P);
142       }
143       // Essential boundary conditions are encoded as -(loc+1), but we don't care so we decode.
144       PetscInt loc = indices[field_offsets[dm_field] + ii*(*num_comp)];
145       restr_indices[cell_offset++] = loc >= 0 ? loc : -(loc + 1);
146     }
147     ierr = DMPlexRestoreClosureIndices(dm, section, section, c, PETSC_TRUE, &num_indices, &indices, field_offsets, NULL);CHKERRQ(ierr);
148   }
149   if (cell_offset != restr_size) SETERRQ3(PETSC_COMM_SELF, PETSC_ERR_SUP, "Shape mismatch, offsets array of shape (%D, %D) initialized for %D nodes", *num_cells, (*cell_size), cell_offset);
150   if (iter_is) { ierr = ISRestoreIndices(iter_is, &iter_indices);CHKERRQ(ierr); }
151   ierr = ISDestroy(&iter_is);CHKERRQ(ierr);
152 
153   *offsets = restr_indices;
154   ierr = PetscSectionGetStorageSize(section, l_size);CHKERRQ(ierr);
155   PetscFunctionReturn(0);
156 }
157 
158 #if defined(PETSC_HAVE_LIBCEED)
159 #include <petscdmplexceed.h>
160 
161 /*@C
162   DMPlexGetCeedRestriction - Define the libCEED map from the local vector (Lvector) to the cells (Evector)
163 
164   Input Parameters:
165   dm - The DMPlex object
166   domain_label - label for DMPlex domain, or NULL for the whole domain
167   label_value - Stratum value
168   height - Height of target cells in DMPlex topology
169   dm_field - Index of DMPlex field
170 
171   Output Parameters:
172   ERestrict - libCEED restriction from local vector to to the cells
173 
174   Level: developer
175 @*/
176 PetscErrorCode DMPlexGetCeedRestriction(DM dm, DMLabel domain_label, PetscInt label_value, PetscInt height, PetscInt dm_field, CeedElemRestriction *ERestrict)
177 {
178   PetscErrorCode ierr;
179 
180   PetscFunctionBeginUser;
181   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
182   PetscValidPointer(ERestrict, 2);
183   if (!dm->ceedERestrict) {
184     PetscInt     num_cells, cell_size, num_comp, lvec_size, *restr_indices;
185     CeedElemRestriction elem_restr;
186     Ceed         ceed;
187 
188     ierr = DMPlexGetLocalOffsets(dm, domain_label, label_value, height, dm_field, &num_cells, &cell_size, &num_comp, &lvec_size, &restr_indices);CHKERRQ(ierr);
189 
190     ierr = DMGetCeed(dm, &ceed);CHKERRQ(ierr);
191     ierr = CeedElemRestrictionCreate(ceed, num_cells, cell_size, num_comp, 1, lvec_size, CEED_MEM_HOST, CEED_COPY_VALUES, restr_indices, &elem_restr);CHKERRQ_CEED(ierr);
192     ierr = PetscFree(restr_indices);CHKERRQ(ierr);
193     dm->ceedERestrict = elem_restr;
194   }
195   *ERestrict = dm->ceedERestrict;
196   PetscFunctionReturn(0);
197 }
198 
199 #endif
200