xref: /petsc/src/dm/impls/plex/plexceed.c (revision d5b43468fb8780a8feea140ccd6fa3e6a50411cc)
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   PetscDS         ds = NULL;
29   PetscFE         fe;
30   PetscSection    section;
31   PetscInt        dim, ds_field = -1;
32   PetscInt       *restr_indices;
33   const PetscInt *iter_indices;
34   IS              iter_is;
35 
36   PetscFunctionBeginUser;
37   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
38   PetscCall(DMGetLocalSection(dm, &section));
39   PetscCall(DMGetDimension(dm, &dim));
40   {
41     IS              field_is;
42     const PetscInt *fields;
43     PetscInt        num_fields;
44 
45     PetscCall(DMGetRegionDS(dm, domain_label, &field_is, &ds));
46     // Translate dm_field to ds_field
47     PetscCall(ISGetIndices(field_is, &fields));
48     PetscCall(ISGetSize(field_is, &num_fields));
49     for (PetscInt i = 0; i < num_fields; i++) {
50       if (dm_field == fields[i]) {
51         ds_field = i;
52         break;
53       }
54     }
55     PetscCall(ISRestoreIndices(field_is, &fields));
56   }
57   PetscCheck(ds_field != -1, PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "Could not find dm_field %" PetscInt_FMT " in DS", dm_field);
58 
59   {
60     PetscInt depth;
61     DMLabel  depth_label;
62     IS       depth_is;
63 
64     PetscCall(DMPlexGetDepth(dm, &depth));
65     PetscCall(DMPlexGetDepthLabel(dm, &depth_label));
66     PetscCall(DMLabelGetStratumIS(depth_label, depth - height, &depth_is));
67     if (domain_label) {
68       IS domain_is;
69 
70       PetscCall(DMLabelGetStratumIS(domain_label, label_value, &domain_is));
71       if (domain_is) { // domainIS is non-empty
72         PetscCall(ISIntersect(depth_is, domain_is, &iter_is));
73         PetscCall(ISDestroy(&domain_is));
74       } else { // domainIS is NULL (empty)
75         iter_is = NULL;
76       }
77       PetscCall(ISDestroy(&depth_is));
78     } else {
79       iter_is = depth_is;
80     }
81     if (iter_is) {
82       PetscCall(ISGetLocalSize(iter_is, num_cells));
83       PetscCall(ISGetIndices(iter_is, &iter_indices));
84     } else {
85       *num_cells   = 0;
86       iter_indices = NULL;
87     }
88   }
89 
90   {
91     PetscDualSpace dual_space;
92     PetscInt       num_dual_basis_vectors;
93 
94     PetscCall(PetscDSGetDiscretization(ds, ds_field, (PetscObject *)&fe));
95     PetscCall(PetscFEGetHeightSubspace(fe, height, &fe));
96     PetscCheck(fe, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Height %" PetscInt_FMT " is invalid for DG coordinates", height);
97     PetscCall(PetscFEGetDualSpace(fe, &dual_space));
98     PetscCall(PetscDualSpaceGetDimension(dual_space, &num_dual_basis_vectors));
99     PetscCall(PetscDualSpaceGetNumComponents(dual_space, num_comp));
100     PetscCheck(num_dual_basis_vectors % *num_comp == 0, PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for number of dual basis vectors %" PetscInt_FMT " not divisible by %" PetscInt_FMT " components", num_dual_basis_vectors, *num_comp);
101     *cell_size = num_dual_basis_vectors / *num_comp;
102   }
103   PetscInt restr_size = (*num_cells) * (*cell_size);
104   PetscCall(PetscMalloc1(restr_size, &restr_indices));
105   PetscInt cell_offset = 0;
106 
107   PetscInt P = (PetscInt)pow(*cell_size, 1.0 / (dim - height));
108   for (PetscInt p = 0; p < *num_cells; p++) {
109     PetscBool flip = PETSC_FALSE;
110     PetscInt  c    = iter_indices[p];
111     PetscInt  num_indices, *indices;
112     PetscInt  field_offsets[17]; // max number of fields plus 1
113     PetscCall(DMPlexGetClosureIndices(dm, section, section, c, PETSC_TRUE, &num_indices, &indices, field_offsets, NULL));
114     if (height > 0) {
115       PetscInt        num_cells_support, num_faces, start = -1;
116       const PetscInt *orients, *faces, *cells;
117       PetscCall(DMPlexGetSupport(dm, c, &cells));
118       PetscCall(DMPlexGetSupportSize(dm, c, &num_cells_support));
119       PetscCheck(num_cells_support == 1, PETSC_COMM_SELF, PETSC_ERR_ARG_INCOMP, "Expected one cell in support of exterior face, but got %" PetscInt_FMT " cells", num_cells_support);
120       PetscCall(DMPlexGetCone(dm, cells[0], &faces));
121       PetscCall(DMPlexGetConeSize(dm, cells[0], &num_faces));
122       for (PetscInt i = 0; i < num_faces; i++) {
123         if (faces[i] == c) start = i;
124       }
125       PetscCheck(start >= 0, PETSC_COMM_SELF, PETSC_ERR_ARG_CORRUPT, "Could not find face %" PetscInt_FMT " in cone of its support", c);
126       PetscCall(DMPlexGetConeOrientation(dm, cells[0], &orients));
127       if (orients[start] < 0) flip = PETSC_TRUE;
128     }
129 
130     for (PetscInt i = 0; i < *cell_size; i++) {
131       PetscInt ii = i;
132       if (flip) {
133         if (*cell_size == P) ii = *cell_size - 1 - i;
134         else if (*cell_size == P * P) {
135           PetscInt row = i / P, col = i % P;
136           ii = row + col * P;
137         } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "No support for flipping point with cell size %" PetscInt_FMT " != P (%" PetscInt_FMT ") or P^2", *cell_size, P);
138       }
139       // Essential boundary conditions are encoded as -(loc+1), but we don't care so we decode.
140       PetscInt loc                 = indices[field_offsets[dm_field] + ii * (*num_comp)];
141       restr_indices[cell_offset++] = loc >= 0 ? loc : -(loc + 1);
142     }
143     PetscCall(DMPlexRestoreClosureIndices(dm, section, section, c, PETSC_TRUE, &num_indices, &indices, field_offsets, NULL));
144   }
145   PetscCheck(cell_offset == restr_size, PETSC_COMM_SELF, PETSC_ERR_SUP, "Shape mismatch, offsets array of shape (%" PetscInt_FMT ", %" PetscInt_FMT ") initialized for %" PetscInt_FMT " nodes", *num_cells, (*cell_size), cell_offset);
146   if (iter_is) PetscCall(ISRestoreIndices(iter_is, &iter_indices));
147   PetscCall(ISDestroy(&iter_is));
148 
149   *offsets = restr_indices;
150   PetscCall(PetscSectionGetStorageSize(section, l_size));
151   PetscFunctionReturn(0);
152 }
153 
154 #if defined(PETSC_HAVE_LIBCEED)
155   #include <petscdmplexceed.h>
156 
157 /*@C
158   DMPlexGetCeedRestriction - Define the libCEED map from the local vector (Lvector) to the cells (Evector)
159 
160   Input Parameters:
161   dm - The DMPlex object
162   domain_label - label for DMPlex domain, or NULL for the whole domain
163   label_value - Stratum value
164   height - Height of target cells in DMPlex topology
165   dm_field - Index of DMPlex field
166 
167   Output Parameters:
168   ERestrict - libCEED restriction from local vector to to the cells
169 
170   Level: developer
171 @*/
172 PetscErrorCode DMPlexGetCeedRestriction(DM dm, DMLabel domain_label, PetscInt label_value, PetscInt height, PetscInt dm_field, CeedElemRestriction *ERestrict)
173 {
174   PetscFunctionBeginUser;
175   PetscValidHeaderSpecific(dm, DM_CLASSID, 1);
176   PetscValidPointer(ERestrict, 2);
177   if (!dm->ceedERestrict) {
178     PetscInt            num_cells, cell_size, num_comp, lvec_size, *restr_indices;
179     CeedElemRestriction elem_restr;
180     Ceed                ceed;
181 
182     PetscCall(DMPlexGetLocalOffsets(dm, domain_label, label_value, height, dm_field, &num_cells, &cell_size, &num_comp, &lvec_size, &restr_indices));
183     PetscCall(DMGetCeed(dm, &ceed));
184     PetscCallCEED(CeedElemRestrictionCreate(ceed, num_cells, cell_size, num_comp, 1, lvec_size, CEED_MEM_HOST, CEED_COPY_VALUES, restr_indices, &elem_restr));
185     PetscCall(PetscFree(restr_indices));
186     dm->ceedERestrict = elem_restr;
187   }
188   *ERestrict = dm->ceedERestrict;
189   PetscFunctionReturn(0);
190 }
191 
192 #endif
193