xref: /petsc/src/dm/impls/da/da1.c (revision d71ae5a4db6382e7f06317b8d368875286fe9008)
1 
2 /*
3    Code for manipulating distributed regular 1d arrays in parallel.
4    This file was created by Peter Mell   6/30/95
5 */
6 
7 #include <petsc/private/dmdaimpl.h> /*I  "petscdmda.h"   I*/
8 
9 #include <petscdraw.h>
10 static PetscErrorCode DMView_DA_1d(DM da, PetscViewer viewer)
11 {
12   PetscMPIInt rank;
13   PetscBool   iascii, isdraw, isglvis, isbinary;
14   DM_DA      *dd = (DM_DA *)da->data;
15 #if defined(PETSC_HAVE_MATLAB)
16   PetscBool ismatlab;
17 #endif
18 
19   PetscFunctionBegin;
20   PetscCallMPI(MPI_Comm_rank(PetscObjectComm((PetscObject)da), &rank));
21 
22   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &iascii));
23   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERDRAW, &isdraw));
24   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERGLVIS, &isglvis));
25   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERBINARY, &isbinary));
26 #if defined(PETSC_HAVE_MATLAB)
27   PetscCall(PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERMATLAB, &ismatlab));
28 #endif
29   if (iascii) {
30     PetscViewerFormat format;
31 
32     PetscCall(PetscViewerGetFormat(viewer, &format));
33     if (format == PETSC_VIEWER_LOAD_BALANCE) {
34       PetscInt      i, nmax = 0, nmin = PETSC_MAX_INT, navg = 0, *nz, nzlocal;
35       DMDALocalInfo info;
36       PetscMPIInt   size;
37       PetscCallMPI(MPI_Comm_size(PetscObjectComm((PetscObject)da), &size));
38       PetscCall(DMDAGetLocalInfo(da, &info));
39       nzlocal = info.xm;
40       PetscCall(PetscMalloc1(size, &nz));
41       PetscCallMPI(MPI_Allgather(&nzlocal, 1, MPIU_INT, nz, 1, MPIU_INT, PetscObjectComm((PetscObject)da)));
42       for (i = 0; i < (PetscInt)size; i++) {
43         nmax = PetscMax(nmax, nz[i]);
44         nmin = PetscMin(nmin, nz[i]);
45         navg += nz[i];
46       }
47       PetscCall(PetscFree(nz));
48       navg = navg / size;
49       PetscCall(PetscViewerASCIIPrintf(viewer, "  Load Balance - Grid Points: Min %" PetscInt_FMT "  avg %" PetscInt_FMT "  max %" PetscInt_FMT "\n", nmin, navg, nmax));
50       PetscFunctionReturn(0);
51     }
52     if (format != PETSC_VIEWER_ASCII_VTK_DEPRECATED && format != PETSC_VIEWER_ASCII_VTK_CELL_DEPRECATED && format != PETSC_VIEWER_ASCII_GLVIS) {
53       DMDALocalInfo info;
54       PetscCall(DMDAGetLocalInfo(da, &info));
55       PetscCall(PetscViewerASCIIPushSynchronized(viewer));
56       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "Processor [%d] M %" PetscInt_FMT " m %" PetscInt_FMT " w %" PetscInt_FMT " s %" PetscInt_FMT "\n", rank, dd->M, dd->m, dd->w, dd->s));
57       PetscCall(PetscViewerASCIISynchronizedPrintf(viewer, "X range of indices: %" PetscInt_FMT " %" PetscInt_FMT "\n", info.xs, info.xs + info.xm));
58       PetscCall(PetscViewerFlush(viewer));
59       PetscCall(PetscViewerASCIIPopSynchronized(viewer));
60     } else if (format == PETSC_VIEWER_ASCII_GLVIS) PetscCall(DMView_DA_GLVis(da, viewer));
61     else PetscCall(DMView_DA_VTK(da, viewer));
62   } else if (isdraw) {
63     PetscDraw draw;
64     double    ymin = -1, ymax = 1, xmin = -1, xmax = dd->M, x;
65     PetscInt  base;
66     char      node[10];
67     PetscBool isnull;
68 
69     PetscCall(PetscViewerDrawGetDraw(viewer, 0, &draw));
70     PetscCall(PetscDrawIsNull(draw, &isnull));
71     if (isnull) PetscFunctionReturn(0);
72 
73     PetscCall(PetscDrawCheckResizedWindow(draw));
74     PetscCall(PetscDrawClear(draw));
75     PetscCall(PetscDrawSetCoordinates(draw, xmin, ymin, xmax, ymax));
76 
77     PetscDrawCollectiveBegin(draw);
78     /* first processor draws all node lines */
79     if (rank == 0) {
80       PetscInt xmin_tmp;
81       ymin = 0.0;
82       ymax = 0.3;
83       for (xmin_tmp = 0; xmin_tmp < dd->M; xmin_tmp++) PetscCall(PetscDrawLine(draw, (double)xmin_tmp, ymin, (double)xmin_tmp, ymax, PETSC_DRAW_BLACK));
84       xmin = 0.0;
85       xmax = dd->M - 1;
86       PetscCall(PetscDrawLine(draw, xmin, ymin, xmax, ymin, PETSC_DRAW_BLACK));
87       PetscCall(PetscDrawLine(draw, xmin, ymax, xmax, ymax, PETSC_DRAW_BLACK));
88     }
89     PetscDrawCollectiveEnd(draw);
90     PetscCall(PetscDrawFlush(draw));
91     PetscCall(PetscDrawPause(draw));
92 
93     PetscDrawCollectiveBegin(draw);
94     /* draw my box */
95     ymin = 0;
96     ymax = 0.3;
97     xmin = dd->xs / dd->w;
98     xmax = (dd->xe / dd->w) - 1;
99     PetscCall(PetscDrawLine(draw, xmin, ymin, xmax, ymin, PETSC_DRAW_RED));
100     PetscCall(PetscDrawLine(draw, xmin, ymin, xmin, ymax, PETSC_DRAW_RED));
101     PetscCall(PetscDrawLine(draw, xmin, ymax, xmax, ymax, PETSC_DRAW_RED));
102     PetscCall(PetscDrawLine(draw, xmax, ymin, xmax, ymax, PETSC_DRAW_RED));
103     /* Put in index numbers */
104     base = dd->base / dd->w;
105     for (x = xmin; x <= xmax; x++) {
106       PetscCall(PetscSNPrintf(node, sizeof(node), "%d", (int)base++));
107       PetscCall(PetscDrawString(draw, x, ymin, PETSC_DRAW_RED, node));
108     }
109     PetscDrawCollectiveEnd(draw);
110     PetscCall(PetscDrawFlush(draw));
111     PetscCall(PetscDrawPause(draw));
112     PetscCall(PetscDrawSave(draw));
113   } else if (isglvis) {
114     PetscCall(DMView_DA_GLVis(da, viewer));
115   } else if (isbinary) {
116     PetscCall(DMView_DA_Binary(da, viewer));
117 #if defined(PETSC_HAVE_MATLAB)
118   } else if (ismatlab) {
119     PetscCall(DMView_DA_Matlab(da, viewer));
120 #endif
121   }
122   PetscFunctionReturn(0);
123 }
124 
125 PetscErrorCode DMSetUp_DA_1D(DM da)
126 {
127   DM_DA          *dd    = (DM_DA *)da->data;
128   const PetscInt  M     = dd->M;
129   const PetscInt  dof   = dd->w;
130   const PetscInt  s     = dd->s;
131   const PetscInt  sDist = s; /* stencil distance in points */
132   const PetscInt *lx    = dd->lx;
133   DMBoundaryType  bx    = dd->bx;
134   MPI_Comm        comm;
135   Vec             local, global;
136   VecScatter      gtol;
137   IS              to, from;
138   PetscBool       flg1 = PETSC_FALSE, flg2 = PETSC_FALSE;
139   PetscMPIInt     rank, size;
140   PetscInt        i, *idx, nn, left, xs, xe, x, Xs, Xe, start, m, IXs, IXe;
141 
142   PetscFunctionBegin;
143   PetscCall(PetscObjectGetComm((PetscObject)da, &comm));
144   PetscCallMPI(MPI_Comm_size(comm, &size));
145   PetscCallMPI(MPI_Comm_rank(comm, &rank));
146 
147   dd->p = 1;
148   dd->n = 1;
149   dd->m = size;
150   m     = dd->m;
151 
152   if (s > 0) {
153     /* if not communicating data then should be ok to have nothing on some processes */
154     PetscCheck(M >= m, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "More processes than data points! %" PetscInt_FMT " %" PetscInt_FMT, m, M);
155     PetscCheck((M - 1) >= s || size <= 1, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Array is too small for stencil! %" PetscInt_FMT " %" PetscInt_FMT, M - 1, s);
156   }
157 
158   /*
159      Determine locally owned region
160      xs is the first local node number, x is the number of local nodes
161   */
162   if (!lx) {
163     PetscCall(PetscMalloc1(m, &dd->lx));
164     PetscCall(PetscOptionsGetBool(((PetscObject)da)->options, ((PetscObject)da)->prefix, "-da_partition_blockcomm", &flg1, NULL));
165     PetscCall(PetscOptionsGetBool(((PetscObject)da)->options, ((PetscObject)da)->prefix, "-da_partition_nodes_at_end", &flg2, NULL));
166     if (flg1) { /* Block Comm type Distribution */
167       xs = rank * M / m;
168       x  = (rank + 1) * M / m - xs;
169     } else if (flg2) { /* The odd nodes are evenly distributed across last nodes */
170       x = (M + rank) / m;
171       if (M / m == x) xs = rank * x;
172       else xs = rank * (x - 1) + (M + rank) % (x * m);
173     } else { /* The odd nodes are evenly distributed across the first k nodes */
174       /* Regular PETSc Distribution */
175       x = M / m + ((M % m) > rank);
176       if (rank >= (M % m)) xs = (rank * (PetscInt)(M / m) + M % m);
177       else xs = rank * (PetscInt)(M / m) + rank;
178     }
179     PetscCallMPI(MPI_Allgather(&xs, 1, MPIU_INT, dd->lx, 1, MPIU_INT, comm));
180     for (i = 0; i < m - 1; i++) dd->lx[i] = dd->lx[i + 1] - dd->lx[i];
181     dd->lx[m - 1] = M - dd->lx[m - 1];
182   } else {
183     x  = lx[rank];
184     xs = 0;
185     for (i = 0; i < rank; i++) xs += lx[i];
186     /* verify that data user provided is consistent */
187     left = xs;
188     for (i = rank; i < size; i++) left += lx[i];
189     PetscCheck(left == M, PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Sum of lx across processors not equal to M %" PetscInt_FMT " %" PetscInt_FMT, left, M);
190   }
191 
192   /*
193    check if the scatter requires more than one process neighbor or wraps around
194    the domain more than once
195   */
196   PetscCheck((x >= s) || ((M <= 1) && (bx != DM_BOUNDARY_PERIODIC)), PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Local x-width of domain x %" PetscInt_FMT " is smaller than stencil width s %" PetscInt_FMT, x, s);
197 
198   xe = xs + x;
199 
200   /* determine ghost region (Xs) and region scattered into (IXs)  */
201   if (xs - sDist > 0) {
202     Xs  = xs - sDist;
203     IXs = xs - sDist;
204   } else {
205     if (bx) Xs = xs - sDist;
206     else Xs = 0;
207     IXs = 0;
208   }
209   if (xe + sDist <= M) {
210     Xe  = xe + sDist;
211     IXe = xe + sDist;
212   } else {
213     if (bx) Xe = xe + sDist;
214     else Xe = M;
215     IXe = M;
216   }
217 
218   if (bx == DM_BOUNDARY_PERIODIC || bx == DM_BOUNDARY_MIRROR) {
219     Xs  = xs - sDist;
220     Xe  = xe + sDist;
221     IXs = xs - sDist;
222     IXe = xe + sDist;
223   }
224 
225   /* allocate the base parallel and sequential vectors */
226   dd->Nlocal = dof * x;
227   PetscCall(VecCreateMPIWithArray(comm, dof, dd->Nlocal, PETSC_DECIDE, NULL, &global));
228   dd->nlocal = dof * (Xe - Xs);
229   PetscCall(VecCreateSeqWithArray(PETSC_COMM_SELF, dof, dd->nlocal, NULL, &local));
230 
231   PetscCall(VecGetOwnershipRange(global, &start, NULL));
232 
233   /* Create Global to Local Vector Scatter Context */
234   /* global to local must retrieve ghost points */
235   PetscCall(ISCreateStride(comm, dof * (IXe - IXs), dof * (IXs - Xs), 1, &to));
236 
237   PetscCall(PetscMalloc1(x + 2 * sDist, &idx));
238 
239   for (i = 0; i < IXs - Xs; i++) idx[i] = -1; /* prepend with -1s if needed for ghosted case*/
240 
241   nn = IXs - Xs;
242   if (bx == DM_BOUNDARY_PERIODIC) { /* Handle all cases with periodic first */
243     for (i = 0; i < sDist; i++) {   /* Left ghost points */
244       if ((xs - sDist + i) >= 0) idx[nn++] = xs - sDist + i;
245       else idx[nn++] = M + (xs - sDist + i);
246     }
247 
248     for (i = 0; i < x; i++) idx[nn++] = xs + i; /* Non-ghost points */
249 
250     for (i = 0; i < sDist; i++) { /* Right ghost points */
251       if ((xe + i) < M) idx[nn++] = xe + i;
252       else idx[nn++] = (xe + i) - M;
253     }
254   } else if (bx == DM_BOUNDARY_MIRROR) { /* Handle all cases with periodic first */
255     for (i = 0; i < (sDist); i++) {      /* Left ghost points */
256       if ((xs - sDist + i) >= 0) idx[nn++] = xs - sDist + i;
257       else idx[nn++] = sDist - i;
258     }
259 
260     for (i = 0; i < x; i++) idx[nn++] = xs + i; /* Non-ghost points */
261 
262     for (i = 0; i < (sDist); i++) { /* Right ghost points */
263       if ((xe + i) < M) idx[nn++] = xe + i;
264       else idx[nn++] = M - (i + 2);
265     }
266   } else { /* Now do all cases with no periodicity */
267     if (0 <= xs - sDist) {
268       for (i = 0; i < sDist; i++) idx[nn++] = xs - sDist + i;
269     } else {
270       for (i = 0; i < xs; i++) idx[nn++] = i;
271     }
272 
273     for (i = 0; i < x; i++) idx[nn++] = xs + i;
274 
275     if ((xe + sDist) <= M) {
276       for (i = 0; i < sDist; i++) idx[nn++] = xe + i;
277     } else {
278       for (i = xe; i < M; i++) idx[nn++] = i;
279     }
280   }
281 
282   PetscCall(ISCreateBlock(comm, dof, nn - IXs + Xs, &idx[IXs - Xs], PETSC_USE_POINTER, &from));
283   PetscCall(VecScatterCreate(global, from, local, to, &gtol));
284   PetscCall(ISDestroy(&to));
285   PetscCall(ISDestroy(&from));
286   PetscCall(VecDestroy(&local));
287   PetscCall(VecDestroy(&global));
288 
289   dd->xs = dof * xs;
290   dd->xe = dof * xe;
291   dd->ys = 0;
292   dd->ye = 1;
293   dd->zs = 0;
294   dd->ze = 1;
295   dd->Xs = dof * Xs;
296   dd->Xe = dof * Xe;
297   dd->Ys = 0;
298   dd->Ye = 1;
299   dd->Zs = 0;
300   dd->Ze = 1;
301 
302   dd->gtol      = gtol;
303   dd->base      = dof * xs;
304   da->ops->view = DMView_DA_1d;
305 
306   /*
307      Set the local to global ordering in the global vector, this allows use
308      of VecSetValuesLocal().
309   */
310   for (i = 0; i < Xe - IXe; i++) idx[nn++] = -1; /* pad with -1s if needed for ghosted case*/
311 
312   PetscCall(ISLocalToGlobalMappingCreate(comm, dof, nn, idx, PETSC_OWN_POINTER, &da->ltogmap));
313 
314   PetscFunctionReturn(0);
315 }
316 
317 /*@C
318    DMDACreate1d - Creates an object that will manage the communication of  one-dimensional
319    regular array data that is distributed across some processors.
320 
321    Collective
322 
323    Input Parameters:
324 +  comm - MPI communicator
325 .  bx - type of ghost cells at the boundary the array should have, if any. Use
326           DM_BOUNDARY_NONE, DM_BOUNDARY_GHOSTED, or DM_BOUNDARY_PERIODIC.
327 .  M - global dimension of the array (that is the number of grid points)
328             from the command line with -da_grid_x <M>)
329 .  dof - number of degrees of freedom per node
330 .  s - stencil width
331 -  lx - array containing number of nodes in the X direction on each processor,
332         or NULL. If non-null, must be of length as the number of processes in the MPI_Comm.
333         The sum of these entries must equal M
334 
335    Output Parameter:
336 .  da - the resulting distributed array object
337 
338    Options Database Key:
339 +  -dm_view - Calls DMView() at the conclusion of DMDACreate1d()
340 .  -da_grid_x <nx> - number of grid points in x direction
341 .  -da_refine_x <rx> - refinement factor
342 -  -da_refine <n> - refine the DMDA n times before creating it
343 
344    Level: beginner
345 
346    Notes:
347    The array data itself is NOT stored in the DMDA, it is stored in Vec objects;
348    The appropriate vector objects can be obtained with calls to DMCreateGlobalVector()
349    and DMCreateLocalVector() and calls to VecDuplicate() if more are needed.
350 
351    You must call DMSetUp() after this call before using this DM.
352 
353    If you wish to use the options database to change values in the DMDA call DMSetFromOptions() after this call
354    but before DMSetUp().
355 
356 .seealso: `DMDestroy()`, `DMView()`, `DMDACreate2d()`, `DMDACreate3d()`, `DMGlobalToLocalBegin()`, `DMDASetRefinementFactor()`,
357           `DMGlobalToLocalEnd()`, `DMLocalToGlobalBegin()`, `DMLocalToLocalBegin()`, `DMLocalToLocalEnd()`, `DMDAGetRefinementFactor()`,
358           `DMDAGetInfo()`, `DMCreateGlobalVector()`, `DMCreateLocalVector()`, `DMDACreateNaturalVector()`, `DMLoad()`, `DMDAGetOwnershipRanges()`,
359           `DMStagCreate1d()`
360 
361 @*/
362 PetscErrorCode DMDACreate1d(MPI_Comm comm, DMBoundaryType bx, PetscInt M, PetscInt dof, PetscInt s, const PetscInt lx[], DM *da)
363 {
364   PetscMPIInt size;
365 
366   PetscFunctionBegin;
367   PetscCall(DMDACreate(comm, da));
368   PetscCall(DMSetDimension(*da, 1));
369   PetscCall(DMDASetSizes(*da, M, 1, 1));
370   PetscCallMPI(MPI_Comm_size(comm, &size));
371   PetscCall(DMDASetNumProcs(*da, size, PETSC_DECIDE, PETSC_DECIDE));
372   PetscCall(DMDASetBoundaryType(*da, bx, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE));
373   PetscCall(DMDASetDof(*da, dof));
374   PetscCall(DMDASetStencilWidth(*da, s));
375   PetscCall(DMDASetOwnershipRanges(*da, lx, NULL, NULL));
376   PetscFunctionReturn(0);
377 }
378