xref: /petsc/src/dm/tutorials/swarm_ex3.c (revision 4e278199b78715991f5c71ebbd945c1489263e6c)
1 
2 static char help[] = "Tests DMSwarm with DMShell\n\n";
3 
4 #include <petscsf.h>
5 #include <petscdm.h>
6 #include <petscdmshell.h>
7 #include <petscdmda.h>
8 #include <petscdmswarm.h>
9 #include <petsc/private/dmimpl.h>
10 
11 PetscErrorCode _DMLocatePoints_DMDARegular_IS(DM dm,Vec pos,IS *iscell)
12 {
13   PetscInt       p,n,bs,npoints,si,sj,milocal,mjlocal,mx,my;
14   DM             dmregular;
15   PetscInt       *cellidx;
16   const PetscScalar *coor;
17   PetscReal      dx,dy;
18   PetscErrorCode ierr;
19   PetscMPIInt    rank;
20 
21   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
22   ierr = VecGetLocalSize(pos,&n);CHKERRQ(ierr);
23   ierr = VecGetBlockSize(pos,&bs);CHKERRQ(ierr);
24   npoints = n/bs;
25 
26   ierr = PetscMalloc1(npoints,&cellidx);CHKERRQ(ierr);
27   ierr = DMGetApplicationContext(dm,(void**)&dmregular);CHKERRQ(ierr);
28   ierr = DMDAGetCorners(dmregular,&si,&sj,NULL,&milocal,&mjlocal,NULL);CHKERRQ(ierr);
29   ierr = DMDAGetInfo(dmregular,NULL,&mx,&my,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL);CHKERRQ(ierr);
30 
31   dx = 2.0/((PetscReal)mx);
32   dy = 2.0/((PetscReal)my);
33 
34   ierr = VecGetArrayRead(pos,&coor);CHKERRQ(ierr);
35   for (p=0; p<npoints; p++) {
36     PetscReal coorx,coory;
37     PetscInt  mi,mj;
38 
39     coorx = PetscRealPart(coor[2*p]);
40     coory = PetscRealPart(coor[2*p+1]);
41 
42     mi = (PetscInt)( (coorx - (-1.0))/dx);
43     mj = (PetscInt)( (coory - (-1.0))/dy);
44 
45     cellidx[p] = DMLOCATEPOINT_POINT_NOT_FOUND;
46 
47     if ((mj >= sj) && (mj < sj + mjlocal)) {
48       if ((mi >= si) && (mi < si + milocal)) {
49         cellidx[p] = (mi-si) + (mj-sj) * milocal;
50       }
51     }
52     if (coorx < -1.0) cellidx[p] = DMLOCATEPOINT_POINT_NOT_FOUND;
53     if (coorx >  1.0) cellidx[p] = DMLOCATEPOINT_POINT_NOT_FOUND;
54     if (coory < -1.0) cellidx[p] = DMLOCATEPOINT_POINT_NOT_FOUND;
55     if (coory >  1.0) cellidx[p] = DMLOCATEPOINT_POINT_NOT_FOUND;
56   }
57   ierr = VecRestoreArrayRead(pos,&coor);CHKERRQ(ierr);
58   ierr = ISCreateGeneral(PETSC_COMM_SELF,npoints,cellidx,PETSC_OWN_POINTER,iscell);CHKERRQ(ierr);
59   PetscFunctionReturn(0);
60 }
61 
62 PetscErrorCode DMLocatePoints_DMDARegular(DM dm,Vec pos,DMPointLocationType ltype, PetscSF cellSF)
63 {
64   IS             iscell;
65   PetscSFNode    *cells;
66   PetscInt       p,bs,npoints,nfound;
67   const PetscInt *boxCells;
68   PetscErrorCode ierr;
69 
70   ierr = _DMLocatePoints_DMDARegular_IS(dm,pos,&iscell);CHKERRQ(ierr);
71   ierr = VecGetLocalSize(pos,&npoints);CHKERRQ(ierr);
72   ierr = VecGetBlockSize(pos,&bs);CHKERRQ(ierr);
73   npoints = npoints / bs;
74 
75   ierr = PetscMalloc1(npoints, &cells);CHKERRQ(ierr);
76   ierr = ISGetIndices(iscell, &boxCells);CHKERRQ(ierr);
77 
78   for (p=0; p<npoints; p++) {
79     cells[p].rank  = 0;
80     cells[p].index = DMLOCATEPOINT_POINT_NOT_FOUND;
81     cells[p].index = boxCells[p];
82   }
83   ierr = ISRestoreIndices(iscell, &boxCells);CHKERRQ(ierr);
84   ierr = ISDestroy(&iscell);CHKERRQ(ierr);
85   nfound = npoints;
86   ierr = PetscSFSetGraph(cellSF, npoints, nfound, NULL, PETSC_OWN_POINTER, cells, PETSC_OWN_POINTER);CHKERRQ(ierr);
87   ierr = ISDestroy(&iscell);CHKERRQ(ierr);
88   PetscFunctionReturn(0);
89 }
90 
91 PetscErrorCode DMGetNeighbors_DMDARegular(DM dm,PetscInt *nneighbors,const PetscMPIInt **neighbors)
92 {
93   DM             dmregular;
94   PetscErrorCode ierr;
95 
96   ierr = DMGetApplicationContext(dm,(void**)&dmregular);CHKERRQ(ierr);
97   ierr = DMGetNeighbors(dmregular,nneighbors,neighbors);CHKERRQ(ierr);
98   PetscFunctionReturn(0);
99 }
100 
101 PetscErrorCode SwarmViewGP(DM dms,const char prefix[])
102 {
103   PetscReal      *array;
104   PetscInt       *iarray;
105   PetscInt       npoints,p,bs;
106   FILE           *fp;
107   char           name[PETSC_MAX_PATH_LEN];
108   PetscMPIInt    rank;
109   PetscErrorCode ierr;
110 
111   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
112   ierr = PetscSNPrintf(name,PETSC_MAX_PATH_LEN-1,"%s-rank%d.gp",prefix,rank);CHKERRQ(ierr);
113   fp = fopen(name,"w");
114   if (!fp) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_FILE_OPEN,"Cannot open file %s",name);
115   ierr = DMSwarmGetLocalSize(dms,&npoints);CHKERRQ(ierr);
116   ierr = DMSwarmGetField(dms,DMSwarmPICField_coor,&bs,NULL,(void**)&array);CHKERRQ(ierr);
117   ierr = DMSwarmGetField(dms,"itag",NULL,NULL,(void**)&iarray);CHKERRQ(ierr);
118   for (p=0; p<npoints; p++) {
119     fprintf(fp,"%+1.4e %+1.4e %1.4e\n",array[2*p],array[2*p+1],(double)iarray[p]);
120   }
121   ierr = DMSwarmRestoreField(dms,"itag",NULL,NULL,(void**)&iarray);CHKERRQ(ierr);
122   ierr = DMSwarmRestoreField(dms,DMSwarmPICField_coor,&bs,NULL,(void**)&array);CHKERRQ(ierr);
123   fclose(fp);
124   PetscFunctionReturn(0);
125 }
126 
127 /*
128  Create a DMShell and attach a regularly spaced DMDA for point location
129  Override methods for point location
130 */
131 PetscErrorCode ex3_1(void)
132 {
133   DM             dms,dmcell,dmregular;
134   PetscMPIInt    rank;
135   PetscInt       p,bs,nlocal,overlap,mx,tk;
136   PetscReal      dx;
137   PetscReal      *array,dt;
138   PetscInt       *iarray;
139   PetscRandom    rand;
140   PetscErrorCode ierr;
141 
142   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
143 
144   /* Create a regularly spaced DMDA */
145   mx = 40;
146   overlap = 0;
147   ierr = DMDACreate2d(PETSC_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_BOX,mx,mx,PETSC_DECIDE,PETSC_DECIDE,1,overlap,NULL,NULL,&dmregular);CHKERRQ(ierr);
148   ierr = DMSetFromOptions(dmregular);CHKERRQ(ierr);
149   ierr = DMSetUp(dmregular);CHKERRQ(ierr);
150 
151   dx = 2.0/((PetscReal)mx);
152   ierr = DMDASetUniformCoordinates(dmregular,-1.0+0.5*dx,1.0-0.5*dx,-1.0+0.5*dx,1.0-0.5*dx,-1.0,1.0);CHKERRQ(ierr);
153 
154   /* Create a DMShell for point location purposes */
155   ierr = DMShellCreate(PETSC_COMM_WORLD,&dmcell);CHKERRQ(ierr);
156   ierr = DMSetApplicationContext(dmcell,(void*)dmregular);CHKERRQ(ierr);
157   dmcell->ops->locatepoints = DMLocatePoints_DMDARegular;
158   dmcell->ops->getneighbors = DMGetNeighbors_DMDARegular;
159 
160   /* Create the swarm */
161   ierr = DMCreate(PETSC_COMM_WORLD,&dms);CHKERRQ(ierr);
162   ierr = DMSetType(dms,DMSWARM);CHKERRQ(ierr);
163   ierr = DMSetDimension(dms,2);CHKERRQ(ierr);
164 
165   ierr = DMSwarmSetType(dms,DMSWARM_PIC);CHKERRQ(ierr);
166   ierr = DMSwarmSetCellDM(dms,dmcell);CHKERRQ(ierr);
167 
168   ierr = DMSwarmRegisterPetscDatatypeField(dms,"itag",1,PETSC_INT);CHKERRQ(ierr);
169   ierr = DMSwarmFinalizeFieldRegister(dms);CHKERRQ(ierr);
170   {
171     PetscInt  si,sj,milocal,mjlocal;
172     const PetscScalar *LA_coors;
173     Vec       coors;
174     PetscInt  cnt;
175 
176     ierr = DMDAGetCorners(dmregular,&si,&sj,NULL,&milocal,&mjlocal,NULL);CHKERRQ(ierr);
177     ierr = DMGetCoordinates(dmregular,&coors);CHKERRQ(ierr);
178     ierr = VecGetArrayRead(coors,&LA_coors);CHKERRQ(ierr);
179     ierr = DMSwarmSetLocalSizes(dms,milocal*mjlocal,4);CHKERRQ(ierr);
180     ierr = DMSwarmGetLocalSize(dms,&nlocal);CHKERRQ(ierr);
181     ierr = DMSwarmGetField(dms,DMSwarmPICField_coor,&bs,NULL,(void**)&array);CHKERRQ(ierr);
182     cnt = 0;
183     ierr = PetscRandomCreate(PETSC_COMM_SELF,&rand);CHKERRQ(ierr);
184     ierr = PetscRandomSetInterval(rand,-1.0,1.0);CHKERRQ(ierr);
185     for (p=0; p<nlocal; p++) {
186       PetscReal px,py,rx,ry,r2;
187 
188       ierr = PetscRandomGetValueReal(rand,&rx);CHKERRQ(ierr);
189       ierr = PetscRandomGetValueReal(rand,&ry);CHKERRQ(ierr);
190 
191       px = PetscRealPart(LA_coors[2*p+0]) + 0.1*rx*dx;
192       py = PetscRealPart(LA_coors[2*p+1]) + 0.1*ry*dx;
193 
194       r2 = px*px + py*py;
195       if (r2 < 0.75*0.75) {
196         array[bs*cnt+0] = px;
197         array[bs*cnt+1] = py;
198         cnt++;
199       }
200     }
201     ierr = PetscRandomDestroy(&rand);CHKERRQ(ierr);
202     ierr = DMSwarmRestoreField(dms,DMSwarmPICField_coor,&bs,NULL,(void**)&array);CHKERRQ(ierr);
203     ierr = VecRestoreArrayRead(coors,&LA_coors);CHKERRQ(ierr);
204     ierr = DMSwarmSetLocalSizes(dms,cnt,4);CHKERRQ(ierr);
205 
206     ierr = DMSwarmGetLocalSize(dms,&nlocal);CHKERRQ(ierr);
207     ierr = DMSwarmGetField(dms,"itag",&bs,NULL,(void**)&iarray);CHKERRQ(ierr);
208     for (p=0; p<nlocal; p++) {
209       iarray[p] = (PetscInt)rank;
210     }
211     ierr = DMSwarmRestoreField(dms,"itag",&bs,NULL,(void**)&iarray);CHKERRQ(ierr);
212   }
213 
214   ierr = DMView(dms,PETSC_VIEWER_STDOUT_WORLD);CHKERRQ(ierr);
215   ierr = SwarmViewGP(dms,"step0");CHKERRQ(ierr);
216 
217   dt = 0.1;
218   for (tk=1; tk<20; tk++) {
219     char prefix[PETSC_MAX_PATH_LEN];
220     ierr = PetscPrintf(PETSC_COMM_WORLD,"Step %D \n",tk);CHKERRQ(ierr);
221     /* push points */
222     ierr = DMSwarmGetLocalSize(dms,&nlocal);CHKERRQ(ierr);
223     ierr = DMSwarmGetField(dms,DMSwarmPICField_coor,&bs,NULL,(void**)&array);CHKERRQ(ierr);
224     for (p=0; p<nlocal; p++) {
225       PetscReal cx,cy,vx,vy;
226 
227       cx = array[2*p];
228       cy = array[2*p+1];
229       vx =  cy;
230       vy = -cx;
231 
232       array[2*p  ] += dt * vx;
233       array[2*p+1] += dt * vy;
234     }
235     ierr = DMSwarmRestoreField(dms,DMSwarmPICField_coor,&bs,NULL,(void**)&array);CHKERRQ(ierr);
236 
237     /* migrate points */
238     ierr = DMSwarmMigrate(dms,PETSC_TRUE);CHKERRQ(ierr);
239     /* view points */
240     ierr = PetscSNPrintf(prefix,PETSC_MAX_PATH_LEN-1,"step%d",tk);CHKERRQ(ierr);
241     /* should use the regular SwarmView() api, not one for a particular type */
242     ierr = SwarmViewGP(dms,prefix);CHKERRQ(ierr);
243   }
244   ierr = DMDestroy(&dmregular);CHKERRQ(ierr);
245   ierr = DMDestroy(&dmcell);CHKERRQ(ierr);
246   ierr = DMDestroy(&dms);CHKERRQ(ierr);
247   PetscFunctionReturn(0);
248 }
249 
250 int main(int argc,char **argv)
251 {
252   PetscErrorCode ierr;
253 
254   ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
255   ierr = ex3_1();CHKERRQ(ierr);
256   ierr = PetscFinalize();
257   return ierr;
258 }
259 
260 /*TEST
261 
262    build:
263       requires: double !complex
264 
265    test:
266       filter: grep -v atomic
267       filter_output: grep -v atomic
268 TEST*/
269