Date: 2026-03-01T05:24:37+00:00

Actual source code: plexsfc.c

      1: #include <petsc/private/dmpleximpl.h>
      2: #include <petscsf.h>
      3: #include <petsc/private/hashset.h>

      5: typedef uint64_t ZCode;

      7: PETSC_HASH_SET(ZSet, ZCode, PetscHash_UInt64, PetscHashEqual)

      9: typedef struct {
     10:   PetscInt i, j, k;
     11: } Ijk;

     13: typedef struct {
     14:   Ijk         eextent;
     15:   Ijk         vextent;
     16:   PetscMPIInt comm_size;
     17:   ZCode      *zstarts;
     18: } ZLayout;

     20: // ***** Overview of ZCode *******
     21: // The SFC uses integer indexing for each dimension and encodes them into a single integer by interleaving the bits of each index.
     22: // This is known as Morton encoding, and is referred to as ZCode in this code.
     23: // So for index i having bits [i2,i1,i0], and similar for indexes j and k, the ZCode (Morton number) would be:
     24: //    [k2,j2,i2,k1,j1,i1,k0,j0,i0]
     25: // This encoding allows for easier traversal of the SFC structure (see https://en.wikipedia.org/wiki/Z-order_curve and `ZStepOct()`).
     26: // `ZEncode()` is used to go from indices to ZCode, while `ZCodeSplit()` goes from ZCode back to indices.

     28: // Decodes the leading interleaved index from a ZCode
     29: // e.g. [k2,j2,i2,k1,j1,i1,k0,j0,i0] -> [i2,i1,i0]
     30: // Magic numbers taken from https://stackoverflow.com/a/18528775/7564988 (translated to octal)
     31: static unsigned ZCodeSplit1(ZCode z)
     32: {
     33:   z &= 0111111111111111111111;
     34:   z = (z | z >> 2) & 0103030303030303030303;
     35:   z = (z | z >> 4) & 0100170017001700170017;
     36:   z = (z | z >> 8) & 0370000037700000377;
     37:   z = (z | z >> 16) & 0370000000000177777;
     38:   z = (z | z >> 32) & 07777777;
     39:   return (unsigned)z;
     40: }

     42: // Encodes the leading interleaved index from a ZCode
     43: // e.g. [i2,i1,i0] -> [0,0,i2,0,0,i1,0,0,i0]
     44: static ZCode ZEncode1(unsigned t)
     45: {
     46:   ZCode z = t;
     47:   z &= 07777777;
     48:   z = (z | z << 32) & 0370000000000177777;
     49:   z = (z | z << 16) & 0370000037700000377;
     50:   z = (z | z << 8) & 0100170017001700170017;
     51:   z = (z | z << 4) & 0103030303030303030303;
     52:   z = (z | z << 2) & 0111111111111111111111;
     53:   return z;
     54: }

     56: // Decodes i j k indices from a ZCode.
     57: // Uses `ZCodeSplit1()` by shifting ZCode so that the leading index is the desired one to decode
     58: static Ijk ZCodeSplit(ZCode z)
     59: {
     60:   Ijk c;
     61:   c.i = ZCodeSplit1(z >> 2);
     62:   c.j = ZCodeSplit1(z >> 1);
     63:   c.k = ZCodeSplit1(z >> 0);
     64:   return c;
     65: }

     67: // Encodes i j k indices to a ZCode.
     68: // Uses `ZCodeEncode1()` by shifting resulting ZCode to the appropriate bit placement
     69: static ZCode ZEncode(Ijk c)
     70: {
     71:   ZCode z = (ZEncode1((unsigned int)c.i) << 2) | (ZEncode1((unsigned int)c.j) << 1) | ZEncode1((unsigned int)c.k);
     72:   return z;
     73: }

     75: static PetscBool IjkActive(Ijk extent, Ijk l)
     76: {
     77:   if (l.i < extent.i && l.j < extent.j && l.k < extent.k) return PETSC_TRUE;
     78:   return PETSC_FALSE;
     79: }

     81: // If z is not the base of an octet (last 3 bits 0), return 0.
     82: //
     83: // If z is the base of an octet, we recursively grow to the biggest structured octet. This is typically useful when a z
     84: // is outside the domain and we wish to skip a (possibly recursively large) octet to find our next interesting point.
     85: static ZCode ZStepOct(ZCode z)
     86: {
     87:   if (PetscUnlikely(z == 0)) return 0; // Infinite loop below if z == 0
     88:   ZCode step = 07;
     89:   for (; (z & step) == 0; step = (step << 3) | 07) { }
     90:   return step >> 3;
     91: }

     93: // Since element/vertex box extents are typically not equal powers of 2, Z codes that lie within the domain are not contiguous.
     94: static PetscErrorCode ZLayoutCreate(PetscMPIInt size, const PetscInt eextent[3], const PetscInt vextent[3], ZLayout *layout)
     95: {
     96:   PetscFunctionBegin;
     97:   layout->eextent.i = eextent[0];
     98:   layout->eextent.j = eextent[1];
     99:   layout->eextent.k = eextent[2];
    100:   layout->vextent.i = vextent[0];
    101:   layout->vextent.j = vextent[1];
    102:   layout->vextent.k = vextent[2];
    103:   layout->comm_size = size;
    104:   layout->zstarts   = NULL;
    105:   PetscCall(PetscMalloc1(size + 1, &layout->zstarts));

    107:   PetscInt total_elems = eextent[0] * eextent[1] * eextent[2];
    108:   ZCode    z           = 0;
    109:   layout->zstarts[0]   = 0;
    110:   // This loop traverses all vertices in the global domain, so is worth making fast. We use ZStepBound
    111:   for (PetscMPIInt r = 0; r < size; r++) {
    112:     PetscInt elems_needed = (total_elems / size) + (total_elems % size > r), count;
    113:     for (count = 0; count < elems_needed; z++) {
    114:       ZCode skip = ZStepOct(z); // optimistically attempt a longer step
    115:       for (ZCode s = skip;; s >>= 3) {
    116:         Ijk trial = ZCodeSplit(z + s);
    117:         if (IjkActive(layout->eextent, trial)) {
    118:           while (count + s + 1 > (ZCode)elems_needed) s >>= 3; // Shrink the octet
    119:           count += s + 1;
    120:           z += s;
    121:           break;
    122:         }
    123:         if (s == 0) { // the whole skip octet is inactive
    124:           z += skip;
    125:           break;
    126:         }
    127:       }
    128:     }
    129:     // Pick up any extra vertices in the Z ordering before the next rank's first owned element.
    130:     //
    131:     // This leads to poorly balanced vertices when eextent is a power of 2, since all the fringe vertices end up
    132:     // on the last rank. A possible solution is to balance the Z-order vertices independently from the cells, which will
    133:     // result in a lot of element closures being remote. We could finish marking boundary conditions, then do a round of
    134:     // vertex ownership smoothing (which would reorder and redistribute vertices without touching element distribution).
    135:     // Another would be to have an analytic ownership criteria for vertices in the fringe veextent - eextent. This would
    136:     // complicate the job of identifying an owner and its offset.
    137:     //
    138:     // The current recommended approach is to let `-dm_distribute 1` (default) resolve vertex ownership. This is
    139:     // *mandatory* with isoperiodicity (except in special cases) to remove standed vertices from local spaces. Here's
    140:     // the issue:
    141:     //
    142:     // Consider this partition on rank 0 (left) and rank 1.
    143:     //
    144:     //    4 --------  5 -- 14 --10 -- 21 --11
    145:     //                |          |          |
    146:     // 7 -- 16 --  8  |          |          |
    147:     // |           |  3 -------  7 -------  9
    148:     // |           |             |          |
    149:     // 4 --------  6 ------ 10   |          |
    150:     // |           |         |   6 -- 16 -- 8
    151:     // |           |         |
    152:     // 3 ---11---  5 --18--  9
    153:     //
    154:     // The periodic face SF looks like
    155:     // [0] Number of roots=21, leaves=1, remote ranks=1
    156:     // [0] 16 <- (0,11)
    157:     // [1] Number of roots=22, leaves=2, remote ranks=2
    158:     // [1] 14 <- (0,18)
    159:     // [1] 21 <- (1,16)
    160:     //
    161:     // In handling face (0,16), rank 0 learns that (0,7) and (0,8) map to (0,3) and (0,5) respectively, thus we won't use
    162:     // the point SF links to (1,4) and (1,5). Rank 1 learns about the periodic mapping of (1,5) while handling face
    163:     // (1,14), but never learns that vertex (1,4) has been mapped to (0,3) by face (0,16).
    164:     //
    165:     // We can relatively easily inform vertex (1,4) of this mapping, but it stays in rank 1's local space despite not
    166:     // being in the closure and thus not being contributed to. This would be mostly harmless except that some viewer
    167:     // routines expect all local points to be somehow significant. It is not easy to analytically remove the (1,4)
    168:     // vertex because the point SF and isoperiodic face SF would need to be updated to account for removal of the
    169:     // stranded vertices.
    170:     for (; z <= ZEncode(layout->vextent); z++) {
    171:       Ijk loc = ZCodeSplit(z);
    172:       if (IjkActive(layout->eextent, loc)) break;
    173:       z += ZStepOct(z);
    174:     }
    175:     layout->zstarts[r + 1] = z;
    176:   }
    177:   layout->zstarts[size] = ZEncode(layout->vextent);
    178:   PetscFunctionReturn(PETSC_SUCCESS);
    179: }

    181: static PetscInt ZLayoutElementsOnRank(const ZLayout *layout, PetscMPIInt rank)
    182: {
    183:   PetscInt remote_elem = 0;
    184:   for (ZCode rz = layout->zstarts[rank]; rz < layout->zstarts[rank + 1]; rz++) {
    185:     Ijk loc = ZCodeSplit(rz);
    186:     if (IjkActive(layout->eextent, loc)) remote_elem++;
    187:     else rz += ZStepOct(rz);
    188:   }
    189:   return remote_elem;
    190: }

    192: static PetscInt ZCodeFind(ZCode key, PetscInt n, const ZCode X[])
    193: {
    194:   PetscInt lo = 0, hi = n;

    196:   if (n == 0) return -1;
    197:   while (hi - lo > 1) {
    198:     PetscInt mid = lo + (hi - lo) / 2;
    199:     if (key < X[mid]) hi = mid;
    200:     else lo = mid;
    201:   }
    202:   return key == X[lo] ? lo : -(lo + (key > X[lo]) + 1);
    203: }

    205: static inline PetscBool IsPointInsideStratum(PetscInt point, PetscInt pStart, PetscInt pEnd)
    206: {
    207:   return (point >= pStart && point < pEnd) ? PETSC_TRUE : PETSC_FALSE;
    208: }

    210: static PetscErrorCode DMPlexCreateBoxMesh_Tensor_SFC_Periodicity_Private(DM dm, const ZLayout *layout, const ZCode *vert_z, PetscSegBuffer per_faces[3], const PetscReal *lower, const PetscReal *upper, const DMBoundaryType *periodicity, PetscSegBuffer donor_face_closure[3], PetscSegBuffer my_donor_faces[3])
    211: {
    212:   MPI_Comm    comm;
    213:   PetscInt    dim, vStart, vEnd;
    214:   PetscMPIInt size;
    215:   PetscSF     face_sfs[3];
    216:   PetscScalar transforms[3][4][4] = {{{0}}};

    218:   PetscFunctionBegin;
    219:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
    220:   PetscCallMPI(MPI_Comm_size(comm, &size));
    221:   PetscCall(DMGetDimension(dm, &dim));
    222:   const PetscInt csize = PetscPowInt(2, dim - 1);
    223:   PetscCall(DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd));

    225:   PetscInt num_directions = 0;
    226:   for (PetscInt direction = 0; direction < dim; direction++) {
    227:     PetscCount   num_faces;
    228:     PetscInt    *faces;
    229:     ZCode       *donor_verts, *donor_minz;
    230:     PetscSFNode *leaf;
    231:     PetscCount   num_multiroots = 0;
    232:     PetscInt     pStart, pEnd;
    233:     PetscBool    sorted;
    234:     PetscInt     inum_faces;

    236:     if (periodicity[direction] != DM_BOUNDARY_PERIODIC) continue;
    237:     PetscCall(PetscSegBufferGetSize(per_faces[direction], &num_faces));
    238:     PetscCall(PetscSegBufferExtractInPlace(per_faces[direction], &faces));
    239:     PetscCall(PetscSegBufferExtractInPlace(donor_face_closure[direction], &donor_verts));
    240:     PetscCall(PetscMalloc1(num_faces, &donor_minz));
    241:     PetscCall(PetscMalloc1(num_faces, &leaf));
    242:     for (PetscCount i = 0; i < num_faces; i++) {
    243:       ZCode minz = donor_verts[i * csize];

    245:       for (PetscInt j = 1; j < csize; j++) minz = PetscMin(minz, donor_verts[i * csize + j]);
    246:       donor_minz[i] = minz;
    247:     }
    248:     PetscCall(PetscIntCast(num_faces, &inum_faces));
    249:     PetscCall(PetscSortedInt64(inum_faces, (const PetscInt64 *)donor_minz, &sorted));
    250:     // If a donor vertex were chosen to broker multiple faces, we would have a logic error.
    251:     // Checking for sorting is a cheap check that there are no duplicates.
    252:     PetscCheck(sorted, PETSC_COMM_SELF, PETSC_ERR_PLIB, "minz not sorted; possible duplicates not checked");
    253:     for (PetscCount i = 0; i < num_faces;) {
    254:       ZCode       z = donor_minz[i];
    255:       PetscMPIInt remote_rank, remote_count = 0;

    257:       PetscCall(PetscMPIIntCast(ZCodeFind(z, size + 1, layout->zstarts), &remote_rank));
    258:       if (remote_rank < 0) remote_rank = -(remote_rank + 1) - 1;
    259:       // Process all the vertices on this rank
    260:       for (ZCode rz = layout->zstarts[remote_rank]; rz < layout->zstarts[remote_rank + 1]; rz++) {
    261:         Ijk loc = ZCodeSplit(rz);

    263:         if (rz == z) {
    264:           leaf[i].rank  = remote_rank;
    265:           leaf[i].index = remote_count;
    266:           i++;
    267:           if (i == num_faces) break;
    268:           z = donor_minz[i];
    269:         }
    270:         if (IjkActive(layout->vextent, loc)) remote_count++;
    271:       }
    272:     }
    273:     PetscCall(PetscFree(donor_minz));
    274:     PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), &face_sfs[num_directions]));
    275:     PetscCall(PetscSFSetGraph(face_sfs[num_directions], vEnd - vStart, inum_faces, NULL, PETSC_USE_POINTER, leaf, PETSC_USE_POINTER));
    276:     const PetscInt *my_donor_degree;
    277:     PetscCall(PetscSFComputeDegreeBegin(face_sfs[num_directions], &my_donor_degree));
    278:     PetscCall(PetscSFComputeDegreeEnd(face_sfs[num_directions], &my_donor_degree));

    280:     for (PetscInt i = 0; i < vEnd - vStart; i++) {
    281:       num_multiroots += my_donor_degree[i];
    282:       if (my_donor_degree[i] == 0) continue;
    283:       PetscAssert(my_donor_degree[i] == 1, PETSC_COMM_SELF, PETSC_ERR_SUP, "Local vertex has multiple faces");
    284:     }
    285:     PetscInt  *my_donors, *donor_indices, *my_donor_indices;
    286:     PetscCount num_my_donors;

    288:     PetscCall(PetscSegBufferGetSize(my_donor_faces[direction], &num_my_donors));
    289:     PetscCheck(num_my_donors == num_multiroots, PETSC_COMM_SELF, PETSC_ERR_SUP, "Donor request (%" PetscCount_FMT ") does not match expected donors (%" PetscCount_FMT ")", num_my_donors, num_multiroots);
    290:     PetscCall(PetscSegBufferExtractInPlace(my_donor_faces[direction], &my_donors));
    291:     PetscCall(PetscMalloc1(vEnd - vStart, &my_donor_indices));
    292:     for (PetscCount i = 0; i < num_my_donors; i++) {
    293:       PetscInt f = my_donors[i];
    294:       PetscInt num_points, *points = NULL, minv = PETSC_INT_MAX;

    296:       PetscCall(DMPlexGetTransitiveClosure(dm, f, PETSC_TRUE, &num_points, &points));
    297:       for (PetscInt j = 0; j < num_points; j++) {
    298:         PetscInt p = points[2 * j];
    299:         if (!IsPointInsideStratum(p, vStart, vEnd)) continue;
    300:         minv = PetscMin(minv, p);
    301:       }
    302:       PetscCall(DMPlexRestoreTransitiveClosure(dm, f, PETSC_TRUE, &num_points, &points));
    303:       PetscAssert(my_donor_degree[minv - vStart] == 1, PETSC_COMM_SELF, PETSC_ERR_SUP, "Local vertex not requested");
    304:       my_donor_indices[minv - vStart] = f;
    305:     }
    306:     PetscCall(PetscMalloc1(num_faces, &donor_indices));
    307:     PetscCall(PetscSFBcastBegin(face_sfs[num_directions], MPIU_INT, my_donor_indices, donor_indices, MPI_REPLACE));
    308:     PetscCall(PetscSFBcastEnd(face_sfs[num_directions], MPIU_INT, my_donor_indices, donor_indices, MPI_REPLACE));
    309:     PetscCall(PetscFree(my_donor_indices));
    310:     // Modify our leafs so they point to donor faces instead of donor minz. Additionally, give them indices as faces.
    311:     for (PetscCount i = 0; i < num_faces; i++) leaf[i].index = donor_indices[i];
    312:     PetscCall(PetscFree(donor_indices));
    313:     PetscCall(DMPlexGetChart(dm, &pStart, &pEnd));
    314:     PetscCall(PetscSFSetGraph(face_sfs[num_directions], pEnd - pStart, inum_faces, faces, PETSC_COPY_VALUES, leaf, PETSC_OWN_POINTER));
    315:     {
    316:       char face_sf_name[PETSC_MAX_PATH_LEN];
    317:       PetscCall(PetscSNPrintf(face_sf_name, sizeof face_sf_name, "Z-order Isoperiodic Faces #%" PetscInt_FMT, num_directions));
    318:       PetscCall(PetscObjectSetName((PetscObject)face_sfs[num_directions], face_sf_name));
    319:     }

    321:     transforms[num_directions][0][0]         = 1;
    322:     transforms[num_directions][1][1]         = 1;
    323:     transforms[num_directions][2][2]         = 1;
    324:     transforms[num_directions][3][3]         = 1;
    325:     transforms[num_directions][direction][3] = upper[direction] - lower[direction];
    326:     num_directions++;
    327:   }

    329:   PetscCall(DMPlexSetIsoperiodicFaceSF(dm, num_directions, face_sfs));
    330:   PetscCall(DMPlexSetIsoperiodicFaceTransform(dm, num_directions, (PetscScalar *)transforms));

    332:   for (PetscInt i = 0; i < num_directions; i++) PetscCall(PetscSFDestroy(&face_sfs[i]));
    333:   PetscFunctionReturn(PETSC_SUCCESS);
    334: }

    336: // This is a DMGlobalToLocalHook that applies the affine offsets. When extended for rotated periodicity, it'll need to
    337: // apply a rotatonal transform and similar operations will be needed for fields (e.g., to rotate a velocity vector).
    338: // We use this crude approach here so we don't have to write new GPU kernels yet.
    339: static PetscErrorCode DMCoordAddPeriodicOffsets_Private(DM dm, Vec g, InsertMode mode, Vec l, void *ctx)
    340: {
    341:   PetscFunctionBegin;
    342:   // These `VecScatter`s should be merged to improve efficiency; the scatters cannot be overlapped.
    343:   for (PetscInt i = 0; i < dm->periodic.num_affines; i++) {
    344:     PetscCall(VecScatterBegin(dm->periodic.affine_to_local[i], dm->periodic.affine[i], l, ADD_VALUES, SCATTER_FORWARD));
    345:     PetscCall(VecScatterEnd(dm->periodic.affine_to_local[i], dm->periodic.affine[i], l, ADD_VALUES, SCATTER_FORWARD));
    346:   }
    347:   PetscFunctionReturn(PETSC_SUCCESS);
    348: }

    350: // Modify index array based on the transformation of `point` for the given section and field
    351: // Used for correcting the sfNatural based on point reorientation
    352: static PetscErrorCode DMPlexOrientFieldPointIndex(DM dm, PetscSection section, PetscInt field, PetscInt array_size, PetscInt array[], PetscInt point, PetscInt orientation)
    353: {
    354:   PetscInt        *copy;
    355:   PetscInt         dof, off, point_ornt[2] = {point, orientation};
    356:   const PetscInt **perms;

    358:   PetscFunctionBeginUser;
    359:   PetscCall(PetscSectionGetFieldPointSyms(section, field, 1, point_ornt, &perms, NULL));
    360:   if (!perms) PetscFunctionReturn(PETSC_SUCCESS); // section may not have symmetries, such as Q2 finite elements
    361:   PetscCall(PetscSectionGetDof(section, point, &dof));
    362:   PetscCall(PetscSectionGetOffset(section, point, &off));
    363:   PetscCheck(off + dof <= array_size, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Section indices exceed index array bounds");
    364:   PetscCall(DMGetWorkArray(dm, dof, MPIU_INT, &copy));
    365:   PetscArraycpy(copy, &array[off], dof);

    367:   for (PetscInt i = 0; i < dof; i++) {
    368:     if (perms[0]) array[off + perms[0][i]] = copy[i];
    369:   }

    371:   PetscCall(PetscSectionRestoreFieldPointSyms(section, field, 1, point_ornt, &perms, NULL));
    372:   PetscCall(DMRestoreWorkArray(dm, dof, MPIU_INT, &copy));
    373:   PetscFunctionReturn(PETSC_SUCCESS);
    374: }

    376: // Modify Vec based on the transformation of `point` for the given section and field
    377: static PetscErrorCode DMPlexOrientFieldPointVec(DM dm, PetscSection section, PetscInt field, Vec V, PetscInt point, PetscInt orientation)
    378: {
    379:   PetscScalar        *copy, *V_arr;
    380:   PetscInt            dof, off, point_ornt[2] = {point, orientation};
    381:   const PetscInt    **perms;
    382:   const PetscScalar **rots;

    384:   PetscFunctionBeginUser;
    385:   PetscCall(PetscSectionGetFieldPointSyms(section, field, 1, point_ornt, &perms, &rots));
    386:   if (!perms) PetscFunctionReturn(PETSC_SUCCESS); // section may not have symmetries, such as Q2 finite elements
    387:   PetscCall(PetscSectionGetDof(section, point, &dof));
    388:   PetscCall(PetscSectionGetOffset(section, point, &off));
    389:   PetscCall(VecGetArray(V, &V_arr));
    390:   PetscCall(DMGetWorkArray(dm, dof, MPIU_SCALAR, &copy));
    391:   PetscArraycpy(copy, &V_arr[off], dof);

    393:   for (PetscInt i = 0; i < dof; i++) {
    394:     if (perms[0]) V_arr[off + perms[0][i]] = copy[i];
    395:     if (rots[0]) V_arr[off + perms[0][i]] *= rots[0][i];
    396:   }

    398:   PetscCall(PetscSectionRestoreFieldPointSyms(section, field, 1, point_ornt, &perms, &rots));
    399:   PetscCall(DMRestoreWorkArray(dm, dof, MPIU_SCALAR, &copy));
    400:   PetscCall(VecRestoreArray(V, &V_arr));
    401:   PetscFunctionReturn(PETSC_SUCCESS);
    402: }

    404: // Reorient the point in the DMPlex while also applying necessary corrections to other structures (e.g. coordinates)
    405: static PetscErrorCode DMPlexOrientPointWithCorrections(DM dm, PetscInt point, PetscInt ornt, PetscSection perm_section, PetscInt perm_length, PetscInt perm[])
    406: {
    407:   // TODO: Potential speed up if we early exit for ornt == 0 (i.e. if ornt is identity, we don't need to do anything)
    408:   PetscFunctionBeginUser;
    409:   PetscCall(DMPlexOrientPoint(dm, point, ornt));

    411:   { // Correct coordinates based on new cone ordering
    412:     DM           cdm;
    413:     PetscSection csection;
    414:     Vec          coordinates;
    415:     PetscInt     pStart, pEnd;

    417:     PetscCall(DMGetCoordinatesLocal(dm, &coordinates));
    418:     PetscCall(DMGetCoordinateDM(dm, &cdm));
    419:     PetscCall(DMGetLocalSection(cdm, &csection));
    420:     PetscCall(PetscSectionGetChart(csection, &pStart, &pEnd));
    421:     if (IsPointInsideStratum(point, pStart, pEnd)) PetscCall(DMPlexOrientFieldPointVec(cdm, csection, 0, coordinates, point, ornt));
    422:   }

    424:   if (perm_section) {
    425:     PetscInt num_fields;
    426:     PetscCall(PetscSectionGetNumFields(perm_section, &num_fields));
    427:     for (PetscInt f = 0; f < num_fields; f++) PetscCall(DMPlexOrientFieldPointIndex(dm, perm_section, f, perm_length, perm, point, ornt));
    428:   }
    429:   PetscFunctionReturn(PETSC_SUCCESS);
    430: }

    432: // Creates SF to communicate data from donor to periodic faces. The data can be different sizes per donor-periodic pair and is given in `point_sizes[]`
    433: static PetscErrorCode CreateDonorToPeriodicSF(DM dm, PetscSF face_sf, PetscInt pStart, PetscInt pEnd, const PetscInt point_sizes[], PetscInt *rootbuffersize, PetscInt *leafbuffersize, PetscBT *rootbt, PetscSF *sf_closure)
    434: {
    435:   MPI_Comm           comm;
    436:   PetscMPIInt        rank;
    437:   PetscInt           nroots, nleaves;
    438:   PetscInt          *rootdata, *leafdata;
    439:   const PetscInt    *filocal;
    440:   const PetscSFNode *firemote;

    442:   PetscFunctionBeginUser;
    443:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
    444:   PetscCallMPI(MPI_Comm_rank(comm, &rank));

    446:   PetscCall(PetscSFGetGraph(face_sf, &nroots, &nleaves, &filocal, &firemote));
    447:   PetscCall(PetscCalloc2(2 * nroots, &rootdata, 2 * nroots, &leafdata));
    448:   for (PetscInt i = 0; i < nleaves; i++) {
    449:     PetscInt point = filocal[i];
    450:     PetscCheck(IsPointInsideStratum(point, pStart, pEnd), PETSC_COMM_SELF, PETSC_ERR_PLIB, "Point %" PetscInt_FMT " in leaves exists outside of stratum [%" PetscInt_FMT ", %" PetscInt_FMT ")", point, pStart, pEnd);
    451:     leafdata[point] = point_sizes[point - pStart];
    452:   }
    453:   PetscCall(PetscSFReduceBegin(face_sf, MPIU_INT, leafdata, rootdata + nroots, MPIU_SUM));
    454:   PetscCall(PetscSFReduceEnd(face_sf, MPIU_INT, leafdata, rootdata + nroots, MPIU_SUM));

    456:   PetscInt root_offset = 0;
    457:   PetscCall(PetscBTCreate(nroots, rootbt));
    458:   for (PetscInt p = 0; p < nroots; p++) {
    459:     const PetscInt *donor_dof = rootdata + nroots;
    460:     if (donor_dof[p] == 0) {
    461:       rootdata[2 * p]     = -1;
    462:       rootdata[2 * p + 1] = -1;
    463:       continue;
    464:     }
    465:     PetscCall(PetscBTSet(*rootbt, p));
    466:     PetscCheck(IsPointInsideStratum(p, pStart, pEnd), PETSC_COMM_SELF, PETSC_ERR_PLIB, "Point %" PetscInt_FMT " in roots exists outside of stratum [%" PetscInt_FMT ", %" PetscInt_FMT ")", p, pStart, pEnd);
    467:     PetscInt p_size = point_sizes[p - pStart];
    468:     PetscCheck(donor_dof[p] == p_size, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Reduced leaf data size (%" PetscInt_FMT ") does not match root data size (%" PetscInt_FMT ")", donor_dof[p], p_size);
    469:     rootdata[2 * p]     = root_offset;
    470:     rootdata[2 * p + 1] = p_size;
    471:     root_offset += p_size;
    472:   }
    473:   PetscCall(PetscSFBcastBegin(face_sf, MPIU_2INT, rootdata, leafdata, MPI_REPLACE));
    474:   PetscCall(PetscSFBcastEnd(face_sf, MPIU_2INT, rootdata, leafdata, MPI_REPLACE));
    475:   // Count how many leaves we need to communicate the closures
    476:   PetscInt leaf_offset = 0;
    477:   for (PetscInt i = 0; i < nleaves; i++) {
    478:     PetscInt point = filocal[i];
    479:     if (leafdata[2 * point + 1] < 0) continue;
    480:     leaf_offset += leafdata[2 * point + 1];
    481:   }

    483:   PetscSFNode *closure_leaf;
    484:   PetscCall(PetscMalloc1(leaf_offset, &closure_leaf));
    485:   leaf_offset = 0;
    486:   for (PetscInt i = 0; i < nleaves; i++) {
    487:     PetscInt point   = filocal[i];
    488:     PetscInt cl_size = leafdata[2 * point + 1];
    489:     if (cl_size < 0) continue;
    490:     for (PetscInt j = 0; j < cl_size; j++) {
    491:       closure_leaf[leaf_offset].rank  = firemote[i].rank;
    492:       closure_leaf[leaf_offset].index = leafdata[2 * point] + j;
    493:       leaf_offset++;
    494:     }
    495:   }

    497:   PetscCall(PetscSFCreate(comm, sf_closure));
    498:   PetscCall(PetscSFSetGraph(*sf_closure, root_offset, leaf_offset, NULL, PETSC_USE_POINTER, closure_leaf, PETSC_OWN_POINTER));
    499:   *rootbuffersize = root_offset;
    500:   *leafbuffersize = leaf_offset;
    501:   PetscCall(PetscFree2(rootdata, leafdata));
    502:   PetscFunctionReturn(PETSC_SUCCESS);
    503: }

    505: // Determine if `key` is in `array`. `array` does NOT need to be sorted
    506: static inline PetscBool SearchIntArray(PetscInt key, PetscInt array_size, const PetscInt array[])
    507: {
    508:   for (PetscInt i = 0; i < array_size; i++)
    509:     if (array[i] == key) return PETSC_TRUE;
    510:   return PETSC_FALSE;
    511: }

    513: // Translate a cone in periodic points to the cone in donor points based on the `periodic2donor` array
    514: static inline PetscErrorCode TranslateConeP2D(const PetscInt periodic_cone[], PetscInt cone_size, const PetscInt periodic2donor[], PetscInt p2d_count, PetscInt p2d_cone[])
    515: {
    516:   PetscFunctionBeginUser;
    517:   for (PetscInt p = 0; p < cone_size; p++) {
    518:     PetscInt p2d_index = -1;
    519:     for (PetscInt p2d = 0; p2d < p2d_count; p2d++) {
    520:       if (periodic2donor[p2d * 2] == periodic_cone[p]) p2d_index = p2d;
    521:     }
    522:     PetscCheck(p2d_index >= 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Could not find periodic point in periodic-to-donor array");
    523:     p2d_cone[p] = periodic2donor[2 * p2d_index + 1];
    524:   }
    525:   PetscFunctionReturn(PETSC_SUCCESS);
    526: }

    528: // Corrects the cone order of periodic faces (and their transitive closure's cones) to match their donor face pair.
    529: //
    530: // This is done by:
    531: // 1. Communicating the donor's vertex coordinates and recursive cones (i.e. its own cone and those of it's constituent edges) to it's periodic pairs
    532: //    - The donor vertices have the isoperiodic transform applied to them such that they should match exactly
    533: // 2. Translating the periodic vertices into the donor vertices point IDs
    534: // 3. Translating the cone of each periodic point into the donor point IDs
    535: // 4. Comparing the periodic-to-donor cone to the donor cone for each point
    536: // 5. Apply the necessary transformation to the periodic cone to make it match the donor cone
    537: static PetscErrorCode DMPlexCorrectOrientationForIsoperiodic(DM dm)
    538: {
    539:   MPI_Comm        comm;
    540:   DM_Plex        *plex = (DM_Plex *)dm->data;
    541:   PetscInt        nroots, nleaves;
    542:   PetscInt       *local_vec_perm = NULL, local_vec_length = 0, *global_vec_perm = NULL, global_vec_length = 0;
    543:   const PetscInt *filocal, coords_field_id = 0;
    544:   DM              cdm;
    545:   PetscSection    csection, localSection = NULL;
    546:   PetscSF         sfNatural_old = NULL;
    547:   Vec             coordinates;
    548:   PetscMPIInt     myrank;
    549:   PetscBool       debug_printing = PETSC_FALSE;

    551:   PetscFunctionBeginUser;
    552:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
    553:   PetscCallMPI(MPI_Comm_rank(comm, &myrank));
    554:   PetscCall(DMGetCoordinatesLocal(dm, &coordinates));
    555:   PetscCheck(coordinates, comm, PETSC_ERR_ARG_WRONGSTATE, "DM must have coordinates to setup isoperiodic");
    556:   PetscCall(DMGetCoordinateDM(dm, &cdm));
    557:   PetscCall(DMGetLocalSection(cdm, &csection));

    559:   PetscCall(DMGetNaturalSF(dm, &sfNatural_old));
    560:   // Prep data for naturalSF correction
    561:   if (plex->periodic.num_face_sfs > 0 && sfNatural_old) {
    562:     PetscSection       globalSection;
    563:     PetscSF            pointSF, sectionSF;
    564:     PetscInt           nleaves;
    565:     const PetscInt    *ilocal;
    566:     const PetscSFNode *iremote;

    568:     // Create global section with just pointSF and including constraints
    569:     PetscCall(DMGetLocalSection(dm, &localSection));
    570:     PetscCall(DMGetPointSF(dm, &pointSF));
    571:     PetscCall(PetscSectionCreateGlobalSection(localSection, pointSF, PETSC_TRUE, PETSC_TRUE, PETSC_FALSE, &globalSection));

    573:     // Set local_vec_perm to be negative values when that dof is not owned by the current rank
    574:     // Dofs that are owned are set to their corresponding global Vec index
    575:     PetscCall(PetscSectionGetStorageSize(globalSection, &global_vec_length));
    576:     PetscCall(PetscSectionGetStorageSize(localSection, &local_vec_length));
    577:     PetscCall(PetscMalloc2(global_vec_length, &global_vec_perm, local_vec_length, &local_vec_perm));
    578:     for (PetscInt i = 0; i < global_vec_length; i++) global_vec_perm[i] = i;
    579:     for (PetscInt i = 0; i < local_vec_length; i++) local_vec_perm[i] = -(i + 1);

    581:     PetscCall(PetscSFCreate(comm, &sectionSF));
    582:     PetscCall(PetscSFSetGraphSection(sectionSF, localSection, globalSection));
    583:     PetscCall(PetscSFGetGraph(sectionSF, NULL, &nleaves, &ilocal, &iremote));
    584:     for (PetscInt l = 0; l < nleaves; l++) {
    585:       if (iremote[l].rank != myrank) continue;
    586:       PetscInt local_index        = ilocal ? ilocal[l] : l;
    587:       local_vec_perm[local_index] = global_vec_perm[iremote[l].index];
    588:     }
    589:     PetscCall(PetscSectionDestroy(&globalSection));
    590:     PetscCall(PetscSFDestroy(&sectionSF));
    591:   }

    593:   // Create sf_vert_coords and sf_face_cones for communicating donor vertices and cones to periodic faces, respectively
    594:   for (PetscInt f = 0; f < plex->periodic.num_face_sfs; f++) {
    595:     PetscSF face_sf                   = plex->periodic.face_sfs[f];
    596:     const PetscScalar (*transform)[4] = (const PetscScalar (*)[4])plex->periodic.transform[f];
    597:     PetscInt *face_vertices_size, *face_cones_size;
    598:     PetscInt  fStart, fEnd, vStart, vEnd, rootnumvert, leafnumvert, rootconesize, leafconesize, dim;
    599:     PetscSF   sf_vert_coords, sf_face_cones;
    600:     PetscBT   rootbt;

    602:     PetscCall(DMGetCoordinateDim(dm, &dim));
    603:     PetscCall(DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd));
    604:     PetscCall(DMPlexGetHeightStratum(dm, 1, &fStart, &fEnd));
    605:     PetscCall(PetscCalloc2(fEnd - fStart, &face_vertices_size, fEnd - fStart, &face_cones_size));

    607:     // Create SFs to communicate donor vertices and donor cones to periodic faces
    608:     for (PetscInt f = fStart, index = 0; f < fEnd; f++, index++) {
    609:       PetscInt cl_size, *closure = NULL, num_vertices = 0;
    610:       PetscCall(DMPlexGetTransitiveClosure(dm, f, PETSC_TRUE, &cl_size, &closure));
    611:       for (PetscInt p = 0; p < cl_size; p++) {
    612:         PetscInt cl_point = closure[2 * p];
    613:         if (IsPointInsideStratum(cl_point, vStart, vEnd)) num_vertices++;
    614:         else {
    615:           PetscInt cone_size;
    616:           PetscCall(DMPlexGetConeSize(dm, cl_point, &cone_size));
    617:           face_cones_size[index] += cone_size + 2;
    618:         }
    619:       }
    620:       face_vertices_size[index] = num_vertices;
    621:       face_cones_size[index] += num_vertices;
    622:       PetscCall(DMPlexRestoreTransitiveClosure(dm, f, PETSC_TRUE, &cl_size, &closure));
    623:     }
    624:     PetscCall(CreateDonorToPeriodicSF(dm, face_sf, fStart, fEnd, face_vertices_size, &rootnumvert, &leafnumvert, &rootbt, &sf_vert_coords));
    625:     PetscCall(PetscBTDestroy(&rootbt));
    626:     PetscCall(CreateDonorToPeriodicSF(dm, face_sf, fStart, fEnd, face_cones_size, &rootconesize, &leafconesize, &rootbt, &sf_face_cones));

    628:     PetscCall(PetscSFGetGraph(face_sf, &nroots, &nleaves, &filocal, NULL));

    630:     PetscReal *leaf_donor_coords;
    631:     PetscInt  *leaf_donor_cones;

    633:     { // Communicate donor coords and cones to the periodic faces
    634:       PetscReal         *mydonor_vertices;
    635:       PetscInt          *mydonor_cones;
    636:       const PetscScalar *coords_arr;

    638:       PetscCall(PetscCalloc2(rootnumvert * dim, &mydonor_vertices, rootconesize, &mydonor_cones));
    639:       PetscCall(VecGetArrayRead(coordinates, &coords_arr));
    640:       for (PetscInt donor_face = 0, donor_vert_offset = 0, donor_cone_offset = 0; donor_face < nroots; donor_face++) {
    641:         if (!PetscBTLookup(rootbt, donor_face)) continue;
    642:         PetscInt cl_size, *closure = NULL;

    644:         PetscCall(DMPlexGetTransitiveClosure(dm, donor_face, PETSC_TRUE, &cl_size, &closure));
    645:         // Pack vertex coordinates
    646:         for (PetscInt p = 0; p < cl_size; p++) {
    647:           PetscInt cl_point = closure[2 * p], dof, offset;
    648:           if (!IsPointInsideStratum(cl_point, vStart, vEnd)) continue;
    649:           mydonor_cones[donor_cone_offset++] = cl_point;
    650:           PetscCall(PetscSectionGetFieldDof(csection, cl_point, coords_field_id, &dof));
    651:           PetscCall(PetscSectionGetFieldOffset(csection, cl_point, coords_field_id, &offset));
    652:           PetscAssert(dof == dim, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Point %" PetscInt_FMT " has dof size %" PetscInt_FMT ", but should match dimension size %" PetscInt_FMT, cl_point, dof, dim);
    653:           // Apply isoperiodic transform to donor vertices such that corresponding periodic vertices should match exactly
    654:           for (PetscInt d = 0; d < dof; d++) mydonor_vertices[donor_vert_offset * dim + d] = PetscRealPart(coords_arr[offset + d]) + PetscRealPart(transform[d][3]);
    655:           donor_vert_offset++;
    656:         }
    657:         // Pack cones of face points (including face itself)
    658:         for (PetscInt p = 0; p < cl_size; p++) {
    659:           PetscInt        cl_point = closure[2 * p], cone_size, depth;
    660:           const PetscInt *cone;

    662:           PetscCall(DMPlexGetConeSize(dm, cl_point, &cone_size));
    663:           PetscCall(DMPlexGetCone(dm, cl_point, &cone));
    664:           PetscCall(DMPlexGetPointDepth(dm, cl_point, &depth));
    665:           if (depth == 0) continue; // don't include vertex depth
    666:           mydonor_cones[donor_cone_offset++] = cone_size;
    667:           mydonor_cones[donor_cone_offset++] = cl_point;
    668:           PetscArraycpy(&mydonor_cones[donor_cone_offset], cone, cone_size);
    669:           donor_cone_offset += cone_size;
    670:         }
    671:         PetscCall(DMPlexRestoreTransitiveClosure(dm, donor_face, PETSC_TRUE, &cl_size, &closure));
    672:       }
    673:       PetscCall(VecRestoreArrayRead(coordinates, &coords_arr));
    674:       PetscCall(PetscBTDestroy(&rootbt));

    676:       MPI_Datatype vertex_unit;
    677:       PetscMPIInt  n;
    678:       PetscCall(PetscMPIIntCast(dim, &n));
    679:       PetscCallMPI(MPI_Type_contiguous(n, MPIU_REAL, &vertex_unit));
    680:       PetscCallMPI(MPI_Type_commit(&vertex_unit));
    681:       PetscCall(PetscMalloc2(leafnumvert * 3, &leaf_donor_coords, leafconesize, &leaf_donor_cones));
    682:       PetscCall(PetscSFBcastBegin(sf_vert_coords, vertex_unit, mydonor_vertices, leaf_donor_coords, MPI_REPLACE));
    683:       PetscCall(PetscSFBcastBegin(sf_face_cones, MPIU_INT, mydonor_cones, leaf_donor_cones, MPI_REPLACE));
    684:       PetscCall(PetscSFBcastEnd(sf_vert_coords, vertex_unit, mydonor_vertices, leaf_donor_coords, MPI_REPLACE));
    685:       PetscCall(PetscSFBcastEnd(sf_face_cones, MPIU_INT, mydonor_cones, leaf_donor_cones, MPI_REPLACE));
    686:       PetscCall(PetscSFDestroy(&sf_vert_coords));
    687:       PetscCall(PetscSFDestroy(&sf_face_cones));
    688:       PetscCallMPI(MPI_Type_free(&vertex_unit));
    689:       PetscCall(PetscFree2(mydonor_vertices, mydonor_cones));
    690:     }

    692:     { // Determine periodic orientation w/rt donor vertices and reorient
    693:       PetscReal tol = PetscSqr(PETSC_MACHINE_EPSILON * 1e3);
    694:       PetscInt *periodic2donor, dm_depth, maxConeSize;
    695:       PetscInt  coords_offset = 0, cones_offset = 0;

    697:       PetscCall(DMPlexGetDepth(dm, &dm_depth));
    698:       PetscCall(DMPlexGetMaxSizes(dm, &maxConeSize, NULL));
    699:       PetscCall(DMGetWorkArray(dm, 2 * PetscPowInt(maxConeSize, dm_depth - 1), MPIU_INT, &periodic2donor));

    701:       // Translate the periodic face vertices into the donor vertices
    702:       // Translation stored in periodic2donor
    703:       for (PetscInt i = 0; i < nleaves; i++) {
    704:         PetscInt  periodic_face = filocal[i], cl_size, num_verts = face_vertices_size[periodic_face - fStart];
    705:         PetscInt  cones_size = face_cones_size[periodic_face - fStart], p2d_count = 0;
    706:         PetscInt *closure = NULL;

    708:         PetscCall(DMPlexGetTransitiveClosure(dm, periodic_face, PETSC_TRUE, &cl_size, &closure));
    709:         for (PetscInt p = 0; p < cl_size; p++) {
    710:           PetscInt     cl_point = closure[2 * p], coords_size, donor_vertex = -1;
    711:           PetscScalar *coords = NULL;

    713:           if (!IsPointInsideStratum(cl_point, vStart, vEnd)) continue;
    714:           PetscCall(DMPlexVecGetClosure(dm, csection, coordinates, cl_point, &coords_size, &coords));
    715:           PetscAssert(coords_size == dim, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Point %" PetscInt_FMT " has dof size %" PetscInt_FMT ", but should match dimension size %" PetscInt_FMT, cl_point, coords_size, dim);

    717:           for (PetscInt v = 0; v < num_verts; v++) {
    718:             PetscReal dist_sqr = 0;
    719:             for (PetscInt d = 0; d < coords_size; d++) dist_sqr += PetscSqr(PetscRealPart(coords[d]) - leaf_donor_coords[(v + coords_offset) * dim + d]);
    720:             if (dist_sqr < tol) {
    721:               donor_vertex = leaf_donor_cones[cones_offset + v];
    722:               break;
    723:             }
    724:           }
    725:           PetscCheck(donor_vertex >= 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Periodic face %" PetscInt_FMT " could not find matching donor vertex for vertex %" PetscInt_FMT, periodic_face, cl_point);
    726:           if (PetscDefined(USE_DEBUG)) {
    727:             for (PetscInt c = 0; c < p2d_count; c++) PetscCheck(periodic2donor[2 * c + 1] != donor_vertex, comm, PETSC_ERR_PLIB, "Found repeated cone_point in periodic_ordering");
    728:           }

    730:           periodic2donor[2 * p2d_count + 0] = cl_point;
    731:           periodic2donor[2 * p2d_count + 1] = donor_vertex;
    732:           p2d_count++;
    733:           PetscCall(DMPlexVecRestoreClosure(dm, csection, coordinates, cl_point, &coords_size, &coords));
    734:         }
    735:         coords_offset += num_verts;
    736:         PetscCall(DMPlexRestoreTransitiveClosure(dm, periodic_face, PETSC_TRUE, &cl_size, &closure));

    738:         { // Determine periodic orientation w/rt donor vertices and reorient
    739:           PetscInt      depth, *p2d_cone, face_is_array[1] = {periodic_face};
    740:           IS           *is_arrays, face_is;
    741:           PetscSection *section_arrays;
    742:           PetscInt     *donor_cone_array = &leaf_donor_cones[cones_offset + num_verts];

    744:           PetscCall(ISCreateGeneral(PETSC_COMM_SELF, 1, face_is_array, PETSC_USE_POINTER, &face_is));
    745:           PetscCall(DMPlexGetConeRecursive(dm, face_is, &depth, &is_arrays, &section_arrays));
    746:           PetscCall(ISDestroy(&face_is));
    747:           PetscCall(DMGetWorkArray(dm, maxConeSize, MPIU_INT, &p2d_cone));
    748:           for (PetscInt d = 0; d < depth - 1; d++) {
    749:             PetscInt        pStart, pEnd;
    750:             PetscSection    section = section_arrays[d];
    751:             const PetscInt *periodic_cone_arrays, *periodic_point_arrays;

    753:             PetscCall(ISGetIndices(is_arrays[d], &periodic_cone_arrays));
    754:             PetscCall(ISGetIndices(is_arrays[d + 1], &periodic_point_arrays)); // Points at d+1 correspond to the cones at d
    755:             PetscCall(PetscSectionGetChart(section_arrays[d], &pStart, &pEnd));
    756:             for (PetscInt p = pStart; p < pEnd; p++) {
    757:               PetscInt periodic_cone_size, periodic_cone_offset, periodic_point = periodic_point_arrays[p];

    759:               PetscCall(PetscSectionGetDof(section, p, &periodic_cone_size));
    760:               PetscCall(PetscSectionGetOffset(section, p, &periodic_cone_offset));
    761:               const PetscInt *periodic_cone = &periodic_cone_arrays[periodic_cone_offset];
    762:               PetscCall(TranslateConeP2D(periodic_cone, periodic_cone_size, periodic2donor, p2d_count, p2d_cone));

    764:               // Find the donor cone that matches the periodic point's cone
    765:               PetscInt  donor_cone_offset = 0, donor_point = -1, *donor_cone = NULL;
    766:               PetscBool cone_matches = PETSC_FALSE;
    767:               while (donor_cone_offset < cones_size - num_verts) {
    768:                 PetscInt donor_cone_size = donor_cone_array[donor_cone_offset];
    769:                 donor_point              = donor_cone_array[donor_cone_offset + 1];
    770:                 donor_cone               = &donor_cone_array[donor_cone_offset + 2];

    772:                 if (donor_cone_size != periodic_cone_size) goto next_cone;
    773:                 for (PetscInt c = 0; c < periodic_cone_size; c++) {
    774:                   cone_matches = SearchIntArray(donor_cone[c], periodic_cone_size, p2d_cone);
    775:                   if (!cone_matches) goto next_cone;
    776:                 }
    777:                 // Save the found donor cone's point to the translation array. These will be used for higher depth points.
    778:                 // i.e. we save the edge translations for when we look for face cones
    779:                 periodic2donor[2 * p2d_count + 0] = periodic_point;
    780:                 periodic2donor[2 * p2d_count + 1] = donor_point;
    781:                 p2d_count++;
    782:                 break;

    784:               next_cone:
    785:                 donor_cone_offset += donor_cone_size + 2;
    786:               }
    787:               PetscCheck(donor_cone_offset < cones_size - num_verts, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Could not find donor cone equivalent to cone of periodic point %" PetscInt_FMT, periodic_point);

    789:               { // Compare the donor cone with the translated periodic cone and reorient
    790:                 PetscInt       ornt;
    791:                 DMPolytopeType cell_type;
    792:                 PetscBool      found;
    793:                 PetscCall(DMPlexGetCellType(dm, periodic_point, &cell_type));
    794:                 PetscCall(DMPolytopeMatchOrientation(cell_type, donor_cone, p2d_cone, &ornt, &found));
    795:                 PetscCheck(found, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Could not find transformation between donor (%" PetscInt_FMT ") and periodic (%" PetscInt_FMT ") cone's", periodic_point, donor_point);
    796:                 if (debug_printing) PetscCall(PetscPrintf(PETSC_COMM_SELF, "Reorienting point %" PetscInt_FMT " by %" PetscInt_FMT "\n", periodic_point, ornt));
    797:                 PetscCall(DMPlexOrientPointWithCorrections(dm, periodic_point, ornt, localSection, local_vec_length, local_vec_perm));
    798:               }
    799:             }
    800:             PetscCall(ISRestoreIndices(is_arrays[d], &periodic_cone_arrays));
    801:             PetscCall(ISRestoreIndices(is_arrays[d + 1], &periodic_point_arrays));
    802:           }
    803:           PetscCall(DMRestoreWorkArray(dm, maxConeSize, MPIU_INT, &p2d_cone));
    804:           PetscCall(DMPlexRestoreConeRecursive(dm, face_is, &depth, &is_arrays, &section_arrays));
    805:         }

    807:         PetscCall(DMPlexRestoreTransitiveClosure(dm, periodic_face, PETSC_TRUE, &cl_size, &closure));
    808:         cones_offset += cones_size;
    809:       }
    810:       PetscCall(DMRestoreWorkArray(dm, 2 * PetscPowInt(maxConeSize, dm_depth - 1), MPIU_INT, &periodic2donor));
    811:     }
    812:     // Re-set local coordinates (i.e. destroy global coordinates if they were modified)
    813:     PetscCall(DMSetCoordinatesLocal(dm, coordinates));

    815:     PetscCall(PetscFree2(leaf_donor_coords, leaf_donor_cones));
    816:     PetscCall(PetscFree2(face_vertices_size, face_cones_size));
    817:   }

    819:   if (sfNatural_old) { // Correct SFNatural based on the permutation of the local vector
    820:     PetscSF      newglob_to_oldglob_sf, sfNatural_old, sfNatural_new;
    821:     PetscSFNode *remote;

    823:     { // Translate permutation of local Vec into permutation of global Vec
    824:       PetscInt g = 0;
    825:       PetscBT  global_vec_check; // Verify that global indices aren't doubled
    826:       PetscCall(PetscBTCreate(global_vec_length, &global_vec_check));
    827:       for (PetscInt l = 0; l < local_vec_length; l++) {
    828:         PetscInt global_index = local_vec_perm[l];
    829:         if (global_index < 0) continue;
    830:         PetscCheck(!PetscBTLookupSet(global_vec_check, global_index), PETSC_COMM_SELF, PETSC_ERR_PLIB, "Found duplicate global index %" PetscInt_FMT " in local_vec_perm", global_index);
    831:         global_vec_perm[g++] = global_index;
    832:       }
    833:       PetscCheck(g == global_vec_length, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Wrong number of non-negative local indices");
    834:       PetscCall(PetscBTDestroy(&global_vec_check));
    835:     }

    837:     PetscCall(PetscMalloc1(global_vec_length, &remote));
    838:     for (PetscInt i = 0; i < global_vec_length; i++) {
    839:       remote[i].rank  = myrank;
    840:       remote[i].index = global_vec_perm[i];
    841:     }
    842:     PetscCall(PetscFree2(global_vec_perm, local_vec_perm));
    843:     PetscCall(PetscSFCreate(comm, &newglob_to_oldglob_sf));
    844:     PetscCall(PetscSFSetGraph(newglob_to_oldglob_sf, global_vec_length, global_vec_length, NULL, PETSC_USE_POINTER, remote, PETSC_OWN_POINTER));
    845:     PetscCall(DMGetNaturalSF(dm, &sfNatural_old));
    846:     PetscCall(PetscSFCompose(newglob_to_oldglob_sf, sfNatural_old, &sfNatural_new));
    847:     PetscCall(DMSetNaturalSF(dm, sfNatural_new));
    848:     PetscCall(PetscSFDestroy(&sfNatural_new));
    849:     PetscCall(PetscSFDestroy(&newglob_to_oldglob_sf));
    850:   }
    851:   PetscFunctionReturn(PETSC_SUCCESS);
    852: }

    854: // Start with an SF for a positive depth (e.g., faces) and create a new SF for matched closure.
    855: //
    856: // Output Arguments:
    857: //
    858: // + closure_sf - augmented point SF (see `DMGetPointSF()`) that includes the faces and all points in its closure. This
    859: //   can be used to create a global section and section SF.
    860: // - is_points - array of index sets for just the points in the closure of `face_sf`. These may be used to apply an affine
    861: //   transformation to periodic dofs; see DMPeriodicCoordinateSetUp_Internal().
    862: //
    863: static PetscErrorCode DMPlexCreateIsoperiodicPointSF_Private(DM dm, PetscInt num_face_sfs, PetscSF *face_sfs, PetscSF *closure_sf, IS **is_points)
    864: {
    865:   MPI_Comm           comm;
    866:   PetscMPIInt        rank;
    867:   PetscSF            point_sf;
    868:   PetscInt           nroots, nleaves;
    869:   const PetscInt    *filocal;
    870:   const PetscSFNode *firemote;

    872:   PetscFunctionBegin;
    873:   PetscCall(PetscObjectGetComm((PetscObject)dm, &comm));
    874:   PetscCallMPI(MPI_Comm_rank(comm, &rank));
    875:   PetscCall(DMGetPointSF(dm, &point_sf)); // Point SF has remote points
    876:   PetscCall(PetscMalloc1(num_face_sfs, is_points));

    878:   PetscCall(DMPlexCorrectOrientationForIsoperiodic(dm));

    880:   for (PetscInt f = 0; f < num_face_sfs; f++) {
    881:     PetscSF   face_sf = face_sfs[f];
    882:     PetscInt *cl_sizes;
    883:     PetscInt  fStart, fEnd, rootbuffersize, leafbuffersize;
    884:     PetscSF   sf_closure;
    885:     PetscBT   rootbt;

    887:     PetscCall(DMPlexGetHeightStratum(dm, 1, &fStart, &fEnd));
    888:     PetscCall(PetscMalloc1(fEnd - fStart, &cl_sizes));
    889:     for (PetscInt f = fStart, index = 0; f < fEnd; f++, index++) {
    890:       PetscInt cl_size, *closure = NULL;
    891:       PetscCall(DMPlexGetTransitiveClosure(dm, f, PETSC_TRUE, &cl_size, &closure));
    892:       cl_sizes[index] = cl_size - 1;
    893:       PetscCall(DMPlexRestoreTransitiveClosure(dm, f, PETSC_TRUE, &cl_size, &closure));
    894:     }

    896:     PetscCall(CreateDonorToPeriodicSF(dm, face_sf, fStart, fEnd, cl_sizes, &rootbuffersize, &leafbuffersize, &rootbt, &sf_closure));
    897:     PetscCall(PetscFree(cl_sizes));
    898:     PetscCall(PetscSFGetGraph(face_sf, &nroots, &nleaves, &filocal, &firemote));

    900:     PetscSFNode *leaf_donor_closure;
    901:     { // Pack root buffer with owner for every point in the root cones
    902:       PetscSFNode       *donor_closure;
    903:       const PetscInt    *pilocal;
    904:       const PetscSFNode *piremote;
    905:       PetscInt           npoints;

    907:       PetscCall(PetscSFGetGraph(point_sf, NULL, &npoints, &pilocal, &piremote));
    908:       PetscCall(PetscCalloc1(rootbuffersize, &donor_closure));
    909:       for (PetscInt p = 0, root_offset = 0; p < nroots; p++) {
    910:         if (!PetscBTLookup(rootbt, p)) continue;
    911:         PetscInt cl_size, *closure = NULL;
    912:         PetscCall(DMPlexGetTransitiveClosure(dm, p, PETSC_TRUE, &cl_size, &closure));
    913:         for (PetscInt j = 1; j < cl_size; j++) {
    914:           PetscInt c = closure[2 * j];
    915:           if (pilocal) {
    916:             PetscInt found = -1;
    917:             if (npoints > 0) PetscCall(PetscFindInt(c, npoints, pilocal, &found));
    918:             if (found >= 0) {
    919:               donor_closure[root_offset++] = piremote[found];
    920:               continue;
    921:             }
    922:           }
    923:           // we own c
    924:           donor_closure[root_offset].rank  = rank;
    925:           donor_closure[root_offset].index = c;
    926:           root_offset++;
    927:         }
    928:         PetscCall(DMPlexRestoreTransitiveClosure(dm, p, PETSC_TRUE, &cl_size, &closure));
    929:       }

    931:       PetscCall(PetscMalloc1(leafbuffersize, &leaf_donor_closure));
    932:       PetscCall(PetscSFBcastBegin(sf_closure, MPIU_SF_NODE, donor_closure, leaf_donor_closure, MPI_REPLACE));
    933:       PetscCall(PetscSFBcastEnd(sf_closure, MPIU_SF_NODE, donor_closure, leaf_donor_closure, MPI_REPLACE));
    934:       PetscCall(PetscSFDestroy(&sf_closure));
    935:       PetscCall(PetscFree(donor_closure));
    936:     }

    938:     PetscSFNode *new_iremote;
    939:     PetscCall(PetscCalloc1(nroots, &new_iremote));
    940:     for (PetscInt i = 0; i < nroots; i++) new_iremote[i].rank = -1;
    941:     // Walk leaves and match vertices
    942:     for (PetscInt i = 0, leaf_offset = 0; i < nleaves; i++) {
    943:       PetscInt  point   = filocal[i], cl_size;
    944:       PetscInt *closure = NULL;
    945:       PetscCall(DMPlexGetTransitiveClosure(dm, point, PETSC_TRUE, &cl_size, &closure));
    946:       for (PetscInt j = 1; j < cl_size; j++) {
    947:         PetscInt    c  = closure[2 * j];
    948:         PetscSFNode lc = leaf_donor_closure[leaf_offset];
    949:         // printf("[%d] face %d.%d: %d ?-- (%d,%d)\n", rank, point, j, c, lc.rank, lc.index);
    950:         if (new_iremote[c].rank == -1) {
    951:           new_iremote[c] = lc;
    952:         } else PetscCheck(new_iremote[c].rank == lc.rank && new_iremote[c].index == lc.index, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Mismatched cone ordering between faces");
    953:         leaf_offset++;
    954:       }
    955:       PetscCall(DMPlexRestoreTransitiveClosure(dm, point, PETSC_TRUE, &cl_size, &closure));
    956:     }
    957:     PetscCall(PetscFree(leaf_donor_closure));

    959:     // Include face points in closure SF
    960:     for (PetscInt i = 0; i < nleaves; i++) new_iremote[filocal[i]] = firemote[i];
    961:     // consolidate leaves
    962:     PetscInt *leafdata;
    963:     PetscCall(PetscMalloc1(nroots, &leafdata));
    964:     PetscInt num_new_leaves = 0;
    965:     for (PetscInt i = 0; i < nroots; i++) {
    966:       if (new_iremote[i].rank == -1) continue;
    967:       new_iremote[num_new_leaves] = new_iremote[i];
    968:       leafdata[num_new_leaves]    = i;
    969:       num_new_leaves++;
    970:     }
    971:     PetscCall(ISCreateGeneral(PETSC_COMM_SELF, num_new_leaves, leafdata, PETSC_COPY_VALUES, &(*is_points)[f]));

    973:     PetscSF csf;
    974:     PetscCall(PetscSFCreate(comm, &csf));
    975:     PetscCall(PetscSFSetGraph(csf, nroots, num_new_leaves, leafdata, PETSC_COPY_VALUES, new_iremote, PETSC_COPY_VALUES));
    976:     PetscCall(PetscFree(new_iremote)); // copy and delete because new_iremote is longer than it needs to be
    977:     PetscCall(PetscFree(leafdata));
    978:     PetscCall(PetscBTDestroy(&rootbt));

    980:     PetscInt npoints;
    981:     PetscCall(PetscSFGetGraph(point_sf, NULL, &npoints, NULL, NULL));
    982:     if (npoints < 0) { // empty point_sf
    983:       *closure_sf = csf;
    984:     } else {
    985:       PetscCall(PetscSFMerge(point_sf, csf, closure_sf));
    986:       PetscCall(PetscSFDestroy(&csf));
    987:     }
    988:     if (f > 0) PetscCall(PetscSFDestroy(&point_sf)); // Only destroy if point_sf is from previous calls to PetscSFMerge
    989:     point_sf = *closure_sf;                          // Use combined point + isoperiodic SF to define point ownership for further face_sf
    990:   }
    991:   PetscCall(PetscObjectSetName((PetscObject)*closure_sf, "Composed Periodic Points"));
    992:   PetscFunctionReturn(PETSC_SUCCESS);
    993: }

    995: static PetscErrorCode DMGetIsoperiodicPointSF_Plex(DM dm, PetscSF *sf)
    996: {
    997:   DM_Plex *plex = (DM_Plex *)dm->data;

    999:   PetscFunctionBegin;
    1000:   if (!plex->periodic.composed_sf) PetscCall(DMPlexCreateIsoperiodicPointSF_Private(dm, plex->periodic.num_face_sfs, plex->periodic.face_sfs, &plex->periodic.composed_sf, &plex->periodic.periodic_points));
    1001:   if (sf) *sf = plex->periodic.composed_sf;
    1002:   PetscFunctionReturn(PETSC_SUCCESS);
    1003: }

    1005: PetscErrorCode DMPlexMigrateIsoperiodicFaceSF_Internal(DM old_dm, DM dm, PetscSF sf_migration)
    1006: {
    1007:   DM_Plex    *plex = (DM_Plex *)old_dm->data;
    1008:   PetscSF     sf_point, *new_face_sfs;
    1009:   PetscMPIInt rank;

    1011:   PetscFunctionBegin;
    1012:   if (!plex->periodic.face_sfs) PetscFunctionReturn(PETSC_SUCCESS);
    1013:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank));
    1014:   PetscCall(DMGetPointSF(dm, &sf_point));
    1015:   PetscCall(PetscMalloc1(plex->periodic.num_face_sfs, &new_face_sfs));

    1017:   for (PetscInt f = 0; f < plex->periodic.num_face_sfs; f++) {
    1018:     PetscInt           old_npoints, new_npoints, old_nleaf, new_nleaf, point_nleaf;
    1019:     PetscSFNode       *new_leafdata, *rootdata, *leafdata;
    1020:     const PetscInt    *old_local, *point_local;
    1021:     const PetscSFNode *old_remote, *point_remote;

    1023:     PetscCall(PetscSFGetGraph(plex->periodic.face_sfs[f], &old_npoints, &old_nleaf, &old_local, &old_remote));
    1024:     PetscCall(PetscSFGetGraph(sf_migration, NULL, &new_nleaf, NULL, NULL));
    1025:     PetscCall(PetscSFGetGraph(sf_point, &new_npoints, &point_nleaf, &point_local, &point_remote));
    1026:     PetscAssert(new_nleaf == new_npoints, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Expected migration leaf space to match new point root space");
    1027:     PetscCall(PetscMalloc3(old_npoints, &rootdata, old_npoints, &leafdata, new_npoints, &new_leafdata));

    1029:     // Fill new_leafdata with new owners of all points
    1030:     for (PetscInt i = 0; i < new_npoints; i++) {
    1031:       new_leafdata[i].rank  = rank;
    1032:       new_leafdata[i].index = i;
    1033:     }
    1034:     for (PetscInt i = 0; i < point_nleaf; i++) {
    1035:       PetscInt j      = point_local[i];
    1036:       new_leafdata[j] = point_remote[i];
    1037:     }
    1038:     // REPLACE is okay because every leaf agrees about the new owners
    1039:     PetscCall(PetscSFReduceBegin(sf_migration, MPIU_SF_NODE, new_leafdata, rootdata, MPI_REPLACE));
    1040:     PetscCall(PetscSFReduceEnd(sf_migration, MPIU_SF_NODE, new_leafdata, rootdata, MPI_REPLACE));
    1041:     // rootdata now contains the new owners

    1043:     // Send to leaves of old space
    1044:     for (PetscInt i = 0; i < old_npoints; i++) {
    1045:       leafdata[i].rank  = -1;
    1046:       leafdata[i].index = -1;
    1047:     }
    1048:     PetscCall(PetscSFBcastBegin(plex->periodic.face_sfs[f], MPIU_SF_NODE, rootdata, leafdata, MPI_REPLACE));
    1049:     PetscCall(PetscSFBcastEnd(plex->periodic.face_sfs[f], MPIU_SF_NODE, rootdata, leafdata, MPI_REPLACE));

    1051:     // Send to new leaf space
    1052:     PetscCall(PetscSFBcastBegin(sf_migration, MPIU_SF_NODE, leafdata, new_leafdata, MPI_REPLACE));
    1053:     PetscCall(PetscSFBcastEnd(sf_migration, MPIU_SF_NODE, leafdata, new_leafdata, MPI_REPLACE));

    1055:     PetscInt     nface = 0, *new_local;
    1056:     PetscSFNode *new_remote;
    1057:     for (PetscInt i = 0; i < new_npoints; i++) nface += (new_leafdata[i].rank >= 0);
    1058:     PetscCall(PetscMalloc1(nface, &new_local));
    1059:     PetscCall(PetscMalloc1(nface, &new_remote));
    1060:     nface = 0;
    1061:     for (PetscInt i = 0; i < new_npoints; i++) {
    1062:       if (new_leafdata[i].rank == -1) continue;
    1063:       new_local[nface]  = i;
    1064:       new_remote[nface] = new_leafdata[i];
    1065:       nface++;
    1066:     }
    1067:     PetscCall(PetscFree3(rootdata, leafdata, new_leafdata));
    1068:     PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), &new_face_sfs[f]));
    1069:     PetscCall(PetscSFSetGraph(new_face_sfs[f], new_npoints, nface, new_local, PETSC_OWN_POINTER, new_remote, PETSC_OWN_POINTER));
    1070:     {
    1071:       char new_face_sf_name[PETSC_MAX_PATH_LEN];
    1072:       PetscCall(PetscSNPrintf(new_face_sf_name, sizeof new_face_sf_name, "Migrated Isoperiodic Faces #%" PetscInt_FMT, f));
    1073:       PetscCall(PetscObjectSetName((PetscObject)new_face_sfs[f], new_face_sf_name));
    1074:     }
    1075:   }

    1077:   PetscCall(DMPlexSetIsoperiodicFaceSF(dm, plex->periodic.num_face_sfs, new_face_sfs));
    1078:   PetscCall(DMPlexSetIsoperiodicFaceTransform(dm, plex->periodic.num_face_sfs, (PetscScalar *)plex->periodic.transform));
    1079:   for (PetscInt f = 0; f < plex->periodic.num_face_sfs; f++) PetscCall(PetscSFDestroy(&new_face_sfs[f]));
    1080:   PetscCall(PetscFree(new_face_sfs));
    1081:   PetscFunctionReturn(PETSC_SUCCESS);
    1082: }

    1084: PetscErrorCode DMPeriodicCoordinateSetUp_Internal(DM dm)
    1085: {
    1086:   DM_Plex   *plex = (DM_Plex *)dm->data;
    1087:   PetscCount count;
    1088:   IS         isdof;
    1089:   PetscInt   dim;

    1091:   PetscFunctionBegin;
    1092:   if (!plex->periodic.face_sfs) PetscFunctionReturn(PETSC_SUCCESS);
    1093:   PetscCheck(plex->periodic.periodic_points, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Isoperiodic PointSF must be created before this function is called");

    1095:   PetscCall(DMGetCoordinateDim(dm, &dim));
    1096:   dm->periodic.num_affines = plex->periodic.num_face_sfs;
    1097:   PetscCall(PetscFree2(dm->periodic.affine_to_local, dm->periodic.affine));
    1098:   PetscCall(PetscMalloc2(dm->periodic.num_affines, &dm->periodic.affine_to_local, dm->periodic.num_affines, &dm->periodic.affine));

    1100:   for (PetscInt f = 0; f < plex->periodic.num_face_sfs; f++) {
    1101:     PetscInt        npoints, vsize, isize;
    1102:     const PetscInt *points;
    1103:     IS              is = plex->periodic.periodic_points[f];
    1104:     PetscSegBuffer  seg;
    1105:     PetscSection    section;
    1106:     PetscInt       *ind;
    1107:     Vec             L, P;
    1108:     VecType         vec_type;
    1109:     VecScatter      scatter;
    1110:     PetscScalar    *x;

    1112:     PetscCall(DMGetLocalSection(dm, &section));
    1113:     PetscCall(PetscSegBufferCreate(sizeof(PetscInt), 32, &seg));
    1114:     PetscCall(ISGetSize(is, &npoints));
    1115:     PetscCall(ISGetIndices(is, &points));
    1116:     for (PetscInt i = 0; i < npoints; i++) {
    1117:       PetscInt point = points[i], off, dof;

    1119:       PetscCall(PetscSectionGetOffset(section, point, &off));
    1120:       PetscCall(PetscSectionGetDof(section, point, &dof));
    1121:       PetscAssert(dof % dim == 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Unexpected dof %" PetscInt_FMT " not divisible by dimension %" PetscInt_FMT, dof, dim);
    1122:       for (PetscInt j = 0; j < dof / dim; j++) {
    1123:         PetscInt *slot;

    1125:         PetscCall(PetscSegBufferGetInts(seg, 1, &slot));
    1126:         *slot = off / dim + j;
    1127:       }
    1128:     }
    1129:     PetscCall(PetscSegBufferGetSize(seg, &count));
    1130:     PetscCall(PetscSegBufferExtractAlloc(seg, &ind));
    1131:     PetscCall(PetscSegBufferDestroy(&seg));
    1132:     PetscCall(PetscIntCast(count, &isize));
    1133:     PetscCall(ISCreateBlock(PETSC_COMM_SELF, dim, isize, ind, PETSC_OWN_POINTER, &isdof));

    1135:     PetscCall(PetscIntCast(count * dim, &vsize));
    1136:     PetscCall(DMGetLocalVector(dm, &L));
    1137:     PetscCall(VecCreate(PETSC_COMM_SELF, &P));
    1138:     PetscCall(VecSetSizes(P, vsize, vsize));
    1139:     PetscCall(VecGetType(L, &vec_type));
    1140:     PetscCall(VecSetType(P, vec_type));
    1141:     PetscCall(VecScatterCreate(P, NULL, L, isdof, &scatter));
    1142:     PetscCall(DMRestoreLocalVector(dm, &L));
    1143:     PetscCall(ISDestroy(&isdof));

    1145:     PetscCall(VecGetArrayWrite(P, &x));
    1146:     for (PetscCount i = 0; i < count; i++) {
    1147:       for (PetscInt j = 0; j < dim; j++) x[i * dim + j] = plex->periodic.transform[f][j][3];
    1148:     }
    1149:     PetscCall(VecRestoreArrayWrite(P, &x));

    1151:     dm->periodic.affine_to_local[f] = scatter;
    1152:     dm->periodic.affine[f]          = P;
    1153:   }
    1154:   PetscCall(DMGlobalToLocalHookAdd(dm, NULL, DMCoordAddPeriodicOffsets_Private, NULL));
    1155:   PetscFunctionReturn(PETSC_SUCCESS);
    1156: }

    1158: PetscErrorCode DMPlexCreateBoxMesh_Tensor_SFC_Internal(DM dm, PetscInt dim, const PetscInt faces[], const PetscReal lower[], const PetscReal upper[], const DMBoundaryType periodicity[], PetscBool interpolate)
    1159: {
    1160:   PetscInt  eextent[3] = {1, 1, 1}, vextent[3] = {1, 1, 1};
    1161:   const Ijk closure_1[] = {
    1162:     {0, 0, 0},
    1163:     {1, 0, 0},
    1164:   };
    1165:   const Ijk closure_2[] = {
    1166:     {0, 0, 0},
    1167:     {1, 0, 0},
    1168:     {1, 1, 0},
    1169:     {0, 1, 0},
    1170:   };
    1171:   const Ijk closure_3[] = {
    1172:     {0, 0, 0},
    1173:     {0, 1, 0},
    1174:     {1, 1, 0},
    1175:     {1, 0, 0},
    1176:     {0, 0, 1},
    1177:     {1, 0, 1},
    1178:     {1, 1, 1},
    1179:     {0, 1, 1},
    1180:   };
    1181:   const Ijk *const closure_dim[] = {NULL, closure_1, closure_2, closure_3};
    1182:   // This must be kept consistent with DMPlexCreateCubeMesh_Internal
    1183:   const PetscInt        face_marker_1[]   = {1, 2};
    1184:   const PetscInt        face_marker_2[]   = {4, 2, 1, 3};
    1185:   const PetscInt        face_marker_3[]   = {6, 5, 3, 4, 1, 2};
    1186:   const PetscInt *const face_marker_dim[] = {NULL, face_marker_1, face_marker_2, face_marker_3};
    1187:   // Orient faces so the normal is in the positive axis and the first vertex is the one closest to zero.
    1188:   // These orientations can be determined by examining cones of a reference quad and hex element.
    1189:   const PetscInt        face_orient_1[]   = {0, 0};
    1190:   const PetscInt        face_orient_2[]   = {-1, 0, 0, -1};
    1191:   const PetscInt        face_orient_3[]   = {-2, 0, -2, 1, -2, 0};
    1192:   const PetscInt *const face_orient_dim[] = {NULL, face_orient_1, face_orient_2, face_orient_3};

    1194:   PetscFunctionBegin;
    1195:   PetscCall(PetscLogEventBegin(DMPLEX_CreateBoxSFC, dm, 0, 0, 0));
    1196:   PetscAssertPointer(dm, 1);
    1198:   PetscCall(DMSetDimension(dm, dim));
    1199:   PetscMPIInt rank, size;
    1200:   PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)dm), &size));
    1201:   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)dm), &rank));
    1202:   for (PetscInt i = 0; i < dim; i++) {
    1203:     eextent[i] = faces[i];
    1204:     vextent[i] = faces[i] + 1;
    1205:   }
    1206:   ZLayout layout;
    1207:   PetscCall(ZLayoutCreate(size, eextent, vextent, &layout));
    1208:   PetscZSet vset; // set of all vertices in the closure of the owned elements
    1209:   PetscCall(PetscZSetCreate(&vset));
    1210:   PetscInt local_elems = 0;
    1211:   for (ZCode z = layout.zstarts[rank]; z < layout.zstarts[rank + 1]; z++) {
    1212:     Ijk loc = ZCodeSplit(z);
    1213:     if (IjkActive(layout.vextent, loc)) PetscCall(PetscZSetAdd(vset, z));
    1214:     else {
    1215:       z += ZStepOct(z);
    1216:       continue;
    1217:     }
    1218:     if (IjkActive(layout.eextent, loc)) {
    1219:       local_elems++;
    1220:       // Add all neighboring vertices to set
    1221:       for (PetscInt n = 0; n < PetscPowInt(2, dim); n++) {
    1222:         Ijk   inc  = closure_dim[dim][n];
    1223:         Ijk   nloc = {loc.i + inc.i, loc.j + inc.j, loc.k + inc.k};
    1224:         ZCode v    = ZEncode(nloc);
    1225:         PetscCall(PetscZSetAdd(vset, v));
    1226:       }
    1227:     }
    1228:   }
    1229:   PetscInt local_verts, off = 0;
    1230:   ZCode   *vert_z;
    1231:   PetscCall(PetscZSetGetSize(vset, &local_verts));
    1232:   PetscCall(PetscMalloc1(local_verts, &vert_z));
    1233:   PetscCall(PetscZSetGetElems(vset, &off, vert_z));
    1234:   PetscCall(PetscZSetDestroy(&vset));
    1235:   // ZCode is unsigned for bitwise convenience, but highest bit should never be set, so can interpret as signed
    1236:   PetscCall(PetscSortInt64(local_verts, (PetscInt64 *)vert_z));

    1238:   PetscCall(DMPlexSetChart(dm, 0, local_elems + local_verts));
    1239:   for (PetscInt e = 0; e < local_elems; e++) PetscCall(DMPlexSetConeSize(dm, e, PetscPowInt(2, dim)));
    1240:   PetscCall(DMSetUp(dm));
    1241:   {
    1242:     PetscInt e = 0;
    1243:     for (ZCode z = layout.zstarts[rank]; z < layout.zstarts[rank + 1]; z++) {
    1244:       Ijk loc = ZCodeSplit(z);
    1245:       if (!IjkActive(layout.eextent, loc)) {
    1246:         z += ZStepOct(z);
    1247:         continue;
    1248:       }
    1249:       PetscInt cone[8], orient[8] = {0};
    1250:       for (PetscInt n = 0; n < PetscPowInt(2, dim); n++) {
    1251:         Ijk      inc  = closure_dim[dim][n];
    1252:         Ijk      nloc = {loc.i + inc.i, loc.j + inc.j, loc.k + inc.k};
    1253:         ZCode    v    = ZEncode(nloc);
    1254:         PetscInt ci   = ZCodeFind(v, local_verts, vert_z);
    1255:         PetscAssert(ci >= 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Did not find neighbor vertex in set");
    1256:         cone[n] = local_elems + ci;
    1257:       }
    1258:       PetscCall(DMPlexSetCone(dm, e, cone));
    1259:       PetscCall(DMPlexSetConeOrientation(dm, e, orient));
    1260:       e++;
    1261:     }
    1262:   }

    1264:   PetscCall(DMPlexSymmetrize(dm));
    1265:   PetscCall(DMPlexStratify(dm));

    1267:   { // Create point SF
    1268:     PetscSF sf;
    1269:     PetscCall(PetscSFCreate(PetscObjectComm((PetscObject)dm), &sf));
    1270:     PetscInt owned_verts = ZCodeFind(layout.zstarts[rank + 1], local_verts, vert_z);
    1271:     if (owned_verts < 0) owned_verts = -(owned_verts + 1); // We don't care whether the key was found
    1272:     PetscInt     num_ghosts = local_verts - owned_verts;   // Due to sorting, owned vertices always come first
    1273:     PetscInt    *local_ghosts;
    1274:     PetscSFNode *ghosts;
    1275:     PetscCall(PetscMalloc1(num_ghosts, &local_ghosts));
    1276:     PetscCall(PetscMalloc1(num_ghosts, &ghosts));
    1277:     for (PetscInt i = 0; i < num_ghosts;) {
    1278:       ZCode       z = vert_z[owned_verts + i];
    1279:       PetscMPIInt remote_rank, remote_count = 0;

    1281:       PetscCall(PetscMPIIntCast(ZCodeFind(z, size + 1, layout.zstarts), &remote_rank));
    1282:       if (remote_rank < 0) remote_rank = -(remote_rank + 1) - 1;
    1283:       // We have a new remote rank; find all the ghost indices (which are contiguous in vert_z)

    1285:       // Count the elements on remote_rank
    1286:       PetscInt remote_elem = ZLayoutElementsOnRank(&layout, remote_rank);

    1288:       // Traverse vertices and make ghost links
    1289:       for (ZCode rz = layout.zstarts[remote_rank]; rz < layout.zstarts[remote_rank + 1]; rz++) {
    1290:         Ijk loc = ZCodeSplit(rz);
    1291:         if (rz == z) {
    1292:           local_ghosts[i] = local_elems + owned_verts + i;
    1293:           ghosts[i].rank  = remote_rank;
    1294:           ghosts[i].index = remote_elem + remote_count;
    1295:           i++;
    1296:           if (i == num_ghosts) break;
    1297:           z = vert_z[owned_verts + i];
    1298:         }
    1299:         if (IjkActive(layout.vextent, loc)) remote_count++;
    1300:         else rz += ZStepOct(rz);
    1301:       }
    1302:     }
    1303:     PetscCall(PetscSFSetGraph(sf, local_elems + local_verts, num_ghosts, local_ghosts, PETSC_OWN_POINTER, ghosts, PETSC_OWN_POINTER));
    1304:     PetscCall(PetscObjectSetName((PetscObject)sf, "SFC Point SF"));
    1305:     PetscCall(DMSetPointSF(dm, sf));
    1306:     PetscCall(PetscSFDestroy(&sf));
    1307:   }
    1308:   {
    1309:     Vec          coordinates;
    1310:     PetscScalar *coords;
    1311:     PetscSection coord_section;
    1312:     PetscInt     coord_size;
    1313:     PetscCall(DMGetCoordinateSection(dm, &coord_section));
    1314:     PetscCall(PetscSectionSetNumFields(coord_section, 1));
    1315:     PetscCall(PetscSectionSetFieldComponents(coord_section, 0, dim));
    1316:     PetscCall(PetscSectionSetChart(coord_section, local_elems, local_elems + local_verts));
    1317:     for (PetscInt v = 0; v < local_verts; v++) {
    1318:       PetscInt point = local_elems + v;
    1319:       PetscCall(PetscSectionSetDof(coord_section, point, dim));
    1320:       PetscCall(PetscSectionSetFieldDof(coord_section, point, 0, dim));
    1321:     }
    1322:     PetscCall(PetscSectionSetUp(coord_section));
    1323:     PetscCall(PetscSectionGetStorageSize(coord_section, &coord_size));
    1324:     PetscCall(VecCreate(PETSC_COMM_SELF, &coordinates));
    1325:     PetscCall(PetscObjectSetName((PetscObject)coordinates, "coordinates"));
    1326:     PetscCall(VecSetSizes(coordinates, coord_size, PETSC_DETERMINE));
    1327:     PetscCall(VecSetBlockSize(coordinates, dim));
    1328:     PetscCall(VecSetType(coordinates, VECSTANDARD));
    1329:     PetscCall(VecGetArray(coordinates, &coords));
    1330:     for (PetscInt v = 0; v < local_verts; v++) {
    1331:       Ijk loc             = ZCodeSplit(vert_z[v]);
    1332:       coords[v * dim + 0] = lower[0] + loc.i * (upper[0] - lower[0]) / layout.eextent.i;
    1333:       if (dim > 1) coords[v * dim + 1] = lower[1] + loc.j * (upper[1] - lower[1]) / layout.eextent.j;
    1334:       if (dim > 2) coords[v * dim + 2] = lower[2] + loc.k * (upper[2] - lower[2]) / layout.eextent.k;
    1335:     }
    1336:     PetscCall(VecRestoreArray(coordinates, &coords));
    1337:     PetscCall(DMSetCoordinatesLocal(dm, coordinates));
    1338:     PetscCall(VecDestroy(&coordinates));
    1339:   }
    1340:   if (interpolate) {
    1341:     PetscCall(DMPlexInterpolateInPlace_Internal(dm));

    1343:     DMLabel label;
    1344:     PetscCall(DMCreateLabel(dm, "Face Sets"));
    1345:     PetscCall(DMGetLabel(dm, "Face Sets", &label));
    1346:     PetscSegBuffer per_faces[3], donor_face_closure[3], my_donor_faces[3];
    1347:     for (PetscInt i = 0; i < 3; i++) {
    1348:       PetscCall(PetscSegBufferCreate(sizeof(PetscInt), 64, &per_faces[i]));
    1349:       PetscCall(PetscSegBufferCreate(sizeof(PetscInt), 64, &my_donor_faces[i]));
    1350:       PetscCall(PetscSegBufferCreate(sizeof(ZCode), 64 * PetscPowInt(2, dim), &donor_face_closure[i]));
    1351:     }
    1352:     PetscInt fStart, fEnd, vStart, vEnd;
    1353:     PetscCall(DMPlexGetHeightStratum(dm, 1, &fStart, &fEnd));
    1354:     PetscCall(DMPlexGetDepthStratum(dm, 0, &vStart, &vEnd));
    1355:     for (PetscInt f = fStart; f < fEnd; f++) {
    1356:       PetscInt npoints, *points = NULL, num_fverts = 0, fverts[8];
    1357:       PetscCall(DMPlexGetTransitiveClosure(dm, f, PETSC_TRUE, &npoints, &points));
    1358:       PetscInt bc_count[6] = {0};
    1359:       for (PetscInt i = 0; i < npoints; i++) {
    1360:         PetscInt p = points[2 * i];
    1361:         if (!IsPointInsideStratum(p, vStart, vEnd)) continue;
    1362:         fverts[num_fverts++] = p;
    1363:         Ijk loc              = ZCodeSplit(vert_z[p - vStart]);
    1364:         // Convention here matches DMPlexCreateCubeMesh_Internal
    1365:         bc_count[0] += loc.i == 0;
    1366:         bc_count[1] += loc.i == layout.vextent.i - 1;
    1367:         bc_count[2] += loc.j == 0;
    1368:         bc_count[3] += loc.j == layout.vextent.j - 1;
    1369:         bc_count[4] += loc.k == 0;
    1370:         bc_count[5] += loc.k == layout.vextent.k - 1;
    1371:       }
    1372:       PetscCall(DMPlexRestoreTransitiveClosure(dm, f, PETSC_TRUE, &npoints, &points));
    1373:       for (PetscInt bc = 0, bc_match = 0; bc < 2 * dim; bc++) {
    1374:         if (bc_count[bc] == PetscPowInt(2, dim - 1)) {
    1375:           PetscCall(DMPlexOrientPoint(dm, f, face_orient_dim[dim][bc]));
    1376:           if (periodicity[bc / 2] == DM_BOUNDARY_PERIODIC) {
    1377:             PetscInt *put;
    1378:             if (bc % 2 == 0) { // donor face; no label
    1379:               PetscCall(PetscSegBufferGet(my_donor_faces[bc / 2], 1, &put));
    1380:               *put = f;
    1381:             } else { // periodic face
    1382:               PetscCall(PetscSegBufferGet(per_faces[bc / 2], 1, &put));
    1383:               *put = f;
    1384:               ZCode *zput;
    1385:               PetscCall(PetscSegBufferGet(donor_face_closure[bc / 2], num_fverts, &zput));
    1386:               for (PetscInt i = 0; i < num_fverts; i++) {
    1387:                 Ijk loc = ZCodeSplit(vert_z[fverts[i] - vStart]);
    1388:                 switch (bc / 2) {
    1389:                 case 0:
    1390:                   loc.i = 0;
    1391:                   break;
    1392:                 case 1:
    1393:                   loc.j = 0;
    1394:                   break;
    1395:                 case 2:
    1396:                   loc.k = 0;
    1397:                   break;
    1398:                 }
    1399:                 *zput++ = ZEncode(loc);
    1400:               }
    1401:             }
    1402:             continue;
    1403:           }
    1404:           PetscAssert(bc_match == 0, PETSC_COMM_SELF, PETSC_ERR_PLIB, "Face matches multiple face sets");
    1405:           PetscCall(DMLabelSetValue(label, f, face_marker_dim[dim][bc]));
    1406:           bc_match++;
    1407:         }
    1408:       }
    1409:     }
    1410:     // Ensure that the Coordinate DM has our new boundary labels
    1411:     DM cdm;
    1412:     PetscCall(DMGetCoordinateDM(dm, &cdm));
    1413:     PetscCall(DMCopyLabels(dm, cdm, PETSC_COPY_VALUES, PETSC_FALSE, DM_COPY_LABELS_FAIL));
    1414:     if (periodicity[0] == DM_BOUNDARY_PERIODIC || (dim > 1 && periodicity[1] == DM_BOUNDARY_PERIODIC) || (dim > 2 && periodicity[2] == DM_BOUNDARY_PERIODIC)) {
    1415:       PetscCall(DMPlexCreateBoxMesh_Tensor_SFC_Periodicity_Private(dm, &layout, vert_z, per_faces, lower, upper, periodicity, donor_face_closure, my_donor_faces));
    1416:     }
    1417:     for (PetscInt i = 0; i < 3; i++) {
    1418:       PetscCall(PetscSegBufferDestroy(&per_faces[i]));
    1419:       PetscCall(PetscSegBufferDestroy(&donor_face_closure[i]));
    1420:       PetscCall(PetscSegBufferDestroy(&my_donor_faces[i]));
    1421:     }
    1422:   }
    1423:   PetscCall(PetscFree(layout.zstarts));
    1424:   PetscCall(PetscFree(vert_z));
    1425:   PetscCall(PetscLogEventEnd(DMPLEX_CreateBoxSFC, dm, 0, 0, 0));
    1426:   PetscFunctionReturn(PETSC_SUCCESS);
    1427: }

    1429: /*@
    1430:   DMPlexSetIsoperiodicFaceSF - Express periodicity from an existing mesh

    1432:   Logically Collective

    1434:   Input Parameters:
    1435: + dm           - The `DMPLEX` on which to set periodicity
    1436: . num_face_sfs - Number of `PetscSF`s in `face_sfs`
    1437: - face_sfs     - Array of `PetscSF` in which roots are (owned) donor faces and leaves are faces that must be matched to a (possibly remote) donor face.

    1439:   Level: advanced

    1441:   Note:
    1442:   One can use `-dm_plex_shape zbox` to use this mode of periodicity, wherein the periodic points are distinct both globally
    1443:   and locally, but are paired when creating a global dof space.

    1445: .seealso: [](ch_unstructured), `DMPLEX`, `DMGetGlobalSection()`, `DMPlexGetIsoperiodicFaceSF()`
    1446: @*/
    1447: PetscErrorCode DMPlexSetIsoperiodicFaceSF(DM dm, PetscInt num_face_sfs, PetscSF *face_sfs)
    1448: {
    1449:   DM_Plex *plex = (DM_Plex *)dm->data;

    1451:   PetscFunctionBegin;
    1453:   if (num_face_sfs) {
    1454:     PetscAssertPointer(face_sfs, 3);
    1455:     PetscCall(PetscObjectComposeFunction((PetscObject)dm, "DMGetIsoperiodicPointSF_C", DMGetIsoperiodicPointSF_Plex));
    1456:   } else PetscCall(PetscObjectComposeFunction((PetscObject)dm, "DMGetIsoperiodicPointSF_C", NULL));
    1457:   if (num_face_sfs == plex->periodic.num_face_sfs && (num_face_sfs == 0 || face_sfs == plex->periodic.face_sfs)) PetscFunctionReturn(PETSC_SUCCESS);
    1458:   PetscCall(DMSetGlobalSection(dm, NULL));

    1460:   for (PetscInt i = 0; i < num_face_sfs; i++) PetscCall(PetscObjectReference((PetscObject)face_sfs[i]));
    1461:   if (plex->periodic.num_face_sfs > 0) {
    1462:     for (PetscInt i = 0; i < plex->periodic.num_face_sfs; i++) PetscCall(PetscSFDestroy(&plex->periodic.face_sfs[i]));
    1463:     PetscCall(PetscFree(plex->periodic.face_sfs));
    1464:   }

    1466:   plex->periodic.num_face_sfs = num_face_sfs;
    1467:   PetscCall(PetscCalloc1(num_face_sfs, &plex->periodic.face_sfs));
    1468:   for (PetscInt i = 0; i < num_face_sfs; i++) plex->periodic.face_sfs[i] = face_sfs[i];

    1470:   DM cdm = dm->coordinates[0].dm; // Can't DMGetCoordinateDM because it automatically creates one
    1471:   if (cdm) {
    1472:     PetscCall(DMPlexSetIsoperiodicFaceSF(cdm, num_face_sfs, face_sfs));
    1473:     if (face_sfs) cdm->periodic.setup = DMPeriodicCoordinateSetUp_Internal;
    1474:   }
    1475:   PetscFunctionReturn(PETSC_SUCCESS);
    1476: }

    1478: /*@C
    1479:   DMPlexGetIsoperiodicFaceSF - Obtain periodicity for a mesh

    1481:   Logically Collective

    1483:   Input Parameter:
    1484: . dm - The `DMPLEX` for which to obtain periodic relation

    1486:   Output Parameters:
    1487: + num_face_sfs - Number of `PetscSF`s in the array
    1488: - face_sfs     - Array of `PetscSF` in which roots are (owned) donor faces and leaves are faces that must be matched to a (possibly remote) donor face.

    1490:   Level: advanced

    1492: .seealso: [](ch_unstructured), `DMPLEX`, `DMGetGlobalSection()`, `DMPlexSetIsoperiodicFaceSF()`
    1493: @*/
    1494: PetscErrorCode DMPlexGetIsoperiodicFaceSF(DM dm, PetscInt *num_face_sfs, const PetscSF **face_sfs)
    1495: {
    1496:   PetscBool isPlex;

    1498:   PetscFunctionBegin;
    1500:   PetscCall(PetscObjectTypeCompare((PetscObject)dm, DMPLEX, &isPlex));
    1501:   if (isPlex) {
    1502:     DM_Plex *plex = (DM_Plex *)dm->data;
    1503:     if (face_sfs) *face_sfs = plex->periodic.face_sfs;
    1504:     if (num_face_sfs) *num_face_sfs = plex->periodic.num_face_sfs;
    1505:   } else {
    1506:     if (face_sfs) *face_sfs = NULL;
    1507:     if (num_face_sfs) *num_face_sfs = 0;
    1508:   }
    1509:   PetscFunctionReturn(PETSC_SUCCESS);
    1510: }

    1512: /*@C
    1513:   DMPlexSetIsoperiodicFaceTransform - set geometric transform from donor to periodic points

    1515:   Logically Collective

    1517:   Input Parameters:
    1518: + dm - `DMPLEX` that has been configured with `DMPlexSetIsoperiodicFaceSF()`
    1519: . n  - Number of transforms in array
    1520: - t  - Array of 4x4 affine transformation basis.

    1522:   Level: advanced

    1524:   Notes:
    1525:   Affine transforms are 4x4 matrices in which the leading 3x3 block expresses a rotation (or identity for no rotation),
    1526:   the last column contains a translation vector, and the bottom row is all zero except the last entry, which must always
    1527:   be 1. This representation is common in geometric modeling and allows affine transformations to be composed using
    1528:   simple matrix multiplication.

    1530:   Although the interface accepts a general affine transform, only affine translation is supported at present.

    1532:   Developer Notes:
    1533:   This interface should be replaced by making BasisTransform public, expanding it to support affine representations, and
    1534:   adding GPU implementations to apply the G2L/L2G transforms.

    1536: .seealso: [](ch_unstructured), `DMPLEX`, `DMGetGlobalSection()`, `DMPlexSetIsoperiodicFaceSF()`
    1537: @*/
    1538: PetscErrorCode DMPlexSetIsoperiodicFaceTransform(DM dm, PetscInt n, const PetscScalar t[])
    1539: {
    1540:   DM_Plex *plex = (DM_Plex *)dm->data;

    1542:   PetscFunctionBegin;
    1544:   PetscCheck(n == plex->periodic.num_face_sfs, PetscObjectComm((PetscObject)dm), PETSC_ERR_ARG_OUTOFRANGE, "Number of transforms (%" PetscInt_FMT ") must equal number of isoperiodc face SFs (%" PetscInt_FMT ")", n, plex->periodic.num_face_sfs);

    1546:   PetscCall(PetscFree(plex->periodic.transform));
    1547:   PetscCall(PetscMalloc1(n, &plex->periodic.transform));
    1548:   for (PetscInt i = 0; i < n; i++) {
    1549:     for (PetscInt j = 0; j < 4; j++) {
    1550:       for (PetscInt k = 0; k < 4; k++) {
    1551:         PetscCheck(j != k || t[i * 16 + j * 4 + k] == 1., PetscObjectComm((PetscObject)dm), PETSC_ERR_SUP, "Rotated transforms not supported");
    1552:         plex->periodic.transform[i][j][k] = t[i * 16 + j * 4 + k];
    1553:       }
    1554:     }
    1555:   }
    1556:   PetscFunctionReturn(PETSC_SUCCESS);
    1557: }