xref: /petsc/src/ksp/pc/impls/gamg/gamg.c (revision fa31c87de1d60fdadb7da5e0dbe7cb0f203ff4fb)
1 /*
2  GAMG geometric-algebric multiogrid PC - Mark Adams 2011
3  */
4 #include <../src/ksp/pc/impls/gamg/gamg.h>
5 
6 #if defined PETSC_USE_LOG
7 PetscLogEvent gamg_setup_events[NUM_SET];
8 #endif
9 
10 #define GAMG_MAXLEVELS 30
11 
12 /*#define GAMG_STAGES*/
13 #if (defined PETSC_USE_LOG && defined GAMG_STAGES)
14 static PetscLogStage gamg_stages[GAMG_MAXLEVELS];
15 #endif
16 
17 /* Private context for the GAMG preconditioner */
18 typedef struct gamg_TAG {
19   PetscInt       m_dim;
20   PetscInt       m_Nlevels;
21   PetscInt       m_data_sz;
22   PetscInt       m_data_rows;
23   PetscInt       m_data_cols;
24   PetscBool      m_useSA;
25   PetscReal     *m_data; /* blocked vector of vertex data on fine grid (coordinates) */
26 } PC_GAMG;
27 
28 /* -------------------------------------------------------------------------- */
29 /*
30    PCSetCoordinates_GAMG
31 
32    Input Parameter:
33    .  pc - the preconditioner context
34 */
35 EXTERN_C_BEGIN
36 #undef __FUNCT__
37 #define __FUNCT__ "PCSetCoordinates_GAMG"
38 PetscErrorCode PCSetCoordinates_GAMG( PC a_pc, PetscInt a_ndm, PetscReal *a_coords )
39 {
40   PC_MG          *mg = (PC_MG*)a_pc->data;
41   PC_GAMG        *pc_gamg = (PC_GAMG*)mg->innerctx;
42   PetscErrorCode ierr;
43   PetscInt       arrsz,bs,my0,kk,ii,jj,nloc,Iend;
44   Mat            Amat = a_pc->pmat;
45   PetscBool      flag;
46   char           str[64];
47 
48   PetscFunctionBegin;
49   ierr  = MatGetBlockSize( Amat, &bs );               CHKERRQ( ierr );
50   ierr  = MatGetOwnershipRange( Amat, &my0, &Iend ); CHKERRQ(ierr);
51   nloc = (Iend-my0)/bs;
52   if((Iend-my0)%bs!=0) SETERRQ1(((PetscObject)Amat)->comm,PETSC_ERR_ARG_WRONG, "Bad local size %d.",nloc);
53 
54   ierr  = PetscOptionsGetString(PETSC_NULL,"-pc_gamg_type",str,64,&flag);    CHKERRQ( ierr );
55   pc_gamg->m_useSA = (PetscBool)(flag && strcmp(str,"sa") == 0);
56 
57   pc_gamg->m_data_rows = 1;
58   if(a_coords == 0) pc_gamg->m_useSA = PETSC_TRUE; /* use SA if no data */
59   if( !pc_gamg->m_useSA ) pc_gamg->m_data_cols = a_ndm; /* coordinates */
60   else{ /* SA: null space vectors */
61     if(a_coords != 0 && bs==1 ) pc_gamg->m_data_cols = 1; /* scalar w/ coords and SA (not needed) */
62     else if(a_coords != 0) pc_gamg->m_data_cols = (a_ndm==2 ? 3 : 6); /* elasticity */
63     else pc_gamg->m_data_cols = bs; /* no data, force SA with constant null space vectors */
64     pc_gamg->m_data_rows = bs;
65   }
66   arrsz = nloc*pc_gamg->m_data_rows*pc_gamg->m_data_cols;
67 
68   /* create data - syntactic sugar that should be refactored at some point */
69   if (!pc_gamg->m_data || (pc_gamg->m_data_sz != arrsz)) {
70     ierr = PetscFree( pc_gamg->m_data );  CHKERRQ(ierr);
71     ierr = PetscMalloc((arrsz+1)*sizeof(double), &pc_gamg->m_data ); CHKERRQ(ierr);
72   }
73   for(kk=0;kk<arrsz;kk++)pc_gamg->m_data[kk] = -999.;
74   pc_gamg->m_data[arrsz] = -99.;
75   /* copy data in - column oriented */
76   if( pc_gamg->m_useSA ) {
77     const PetscInt M = Iend - my0;
78     for(kk=0;kk<nloc;kk++){
79       PetscReal *data = &pc_gamg->m_data[kk*bs];
80       if( pc_gamg->m_data_cols==1 ) *data = 1.0;
81       else {
82         for(ii=0;ii<bs;ii++)
83 	  for(jj=0;jj<bs;jj++)
84 	    if(ii==jj)data[ii*M + jj] = 1.0; /* translational modes */
85 	    else data[ii*M + jj] = 0.0;
86         if( a_coords != 0 ) {
87           if( a_ndm == 2 ){ /* rotational modes */
88             data += 2*M;
89             data[0] = -a_coords[2*kk+1];
90             data[1] =  a_coords[2*kk];
91           }
92           else {
93             data += 3*M;
94             data[0] = 0.0;               data[M+0] =  a_coords[3*kk+2]; data[2*M+0] = -a_coords[3*kk+1];
95             data[1] = -a_coords[3*kk+2]; data[M+1] = 0.0;               data[2*M+1] =  a_coords[3*kk];
96             data[2] =  a_coords[3*kk+1]; data[M+2] = -a_coords[3*kk];   data[2*M+2] = 0.0;
97           }
98         }
99       }
100     }
101   }
102   else {
103     for( kk = 0 ; kk < nloc ; kk++ ){
104       for( ii = 0 ; ii < a_ndm ; ii++ ) {
105         pc_gamg->m_data[ii*nloc + kk] =  a_coords[kk*a_ndm + ii];
106       }
107     }
108   }
109   assert(pc_gamg->m_data[arrsz] == -99.);
110 
111   pc_gamg->m_data_sz = arrsz;
112   pc_gamg->m_dim = a_ndm;
113 
114   PetscFunctionReturn(0);
115 }
116 EXTERN_C_END
117 
118 
119 /* -----------------------------------------------------------------------------*/
120 #undef __FUNCT__
121 #define __FUNCT__ "PCReset_GAMG"
122 PetscErrorCode PCReset_GAMG(PC pc)
123 {
124   PetscErrorCode  ierr;
125   PC_MG           *mg = (PC_MG*)pc->data;
126   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
127 
128   PetscFunctionBegin;
129   ierr = PetscFree(pc_gamg->m_data);CHKERRQ(ierr);
130   pc_gamg->m_data = 0; pc_gamg->m_data_sz = 0;
131   PetscFunctionReturn(0);
132 }
133 
134 /* -------------------------------------------------------------------------- */
135 /*
136    partitionLevel
137 
138    Input Parameter:
139    . a_Amat_fine - matrix on this fine (k) level
140    . a_ndata_rows - size of data to move (coarse grid)
141    . a_ndata_cols - size of data to move (coarse grid)
142    In/Output Parameter:
143    . a_P_inout - prolongation operator to the next level (k-1)
144    . a_coarse_data - data that need to be moved
145    . a_nactive_proc - number of active procs
146    Output Parameter:
147    . a_Amat_crs - coarse matrix that is created (k-1)
148 */
149 
150 #define MIN_EQ_PROC 600
151 #define TOP_GRID_LIM 1000
152 
153 #undef __FUNCT__
154 #define __FUNCT__ "partitionLevel"
155 PetscErrorCode partitionLevel( Mat a_Amat_fine,
156                                PetscInt a_ndata_rows,
157                                PetscInt a_ndata_cols,
158 			       PetscInt a_cbs,
159                                Mat *a_P_inout,
160                                PetscReal **a_coarse_data,
161                                PetscMPIInt *a_nactive_proc,
162                                Mat *a_Amat_crs
163                                )
164 {
165   PetscErrorCode   ierr;
166   Mat              Cmat,Pnew,Pold=*a_P_inout;
167   IS               new_indices,isnum;
168   MPI_Comm         wcomm = ((PetscObject)a_Amat_fine)->comm;
169   PetscMPIInt      mype,npe,new_npe,nactive;
170   PetscInt         neq,NN,Istart,Iend,Istart0,Iend0,ncrs_new,ncrs0;
171   PetscBool        flag = PETSC_FALSE;
172 
173   PetscFunctionBegin;
174   ierr = MPI_Comm_rank( wcomm, &mype ); CHKERRQ(ierr);
175   ierr = MPI_Comm_size( wcomm, &npe );  CHKERRQ(ierr);
176   /* RAP */
177   ierr = MatPtAP( a_Amat_fine, Pold, MAT_INITIAL_MATRIX, 2.0, &Cmat ); CHKERRQ(ierr);
178 
179   ierr = MatSetBlockSize( Cmat, a_cbs );      CHKERRQ(ierr);
180   ierr = MatGetOwnershipRange( Cmat, &Istart0, &Iend0 ); CHKERRQ(ierr);
181   ncrs0 = (Iend0-Istart0)/a_cbs; assert((Iend0-Istart0)%a_cbs == 0);
182 
183   ierr  = PetscOptionsHasName(PETSC_NULL,"-pc_gamg_avoid_repartitioning",&flag);
184   CHKERRQ( ierr );
185   if( flag ) {
186     *a_Amat_crs = Cmat; /* output */
187   }
188   else {
189     /* Repartition Cmat_{k} and move colums of P^{k}_{k-1} and coordinates accordingly */
190     Mat              adj;
191     const PetscInt *idx,data_sz=a_ndata_rows*a_ndata_cols;
192     const PetscInt  stride0=ncrs0*a_ndata_rows;
193     PetscInt        is_sz,*isnewproc_idx,ii,jj,kk,strideNew,*tidx;
194     /* create sub communicator  */
195     MPI_Comm        cm,new_comm;
196     MPI_Group       wg, g2;
197     PetscInt       *counts,inpe;
198     PetscMPIInt    *ranks;
199     IS              isscat;
200     PetscScalar    *array;
201     Vec             src_crd, dest_crd;
202     PetscReal      *data = *a_coarse_data;
203     VecScatter      vecscat;
204     IS  isnewproc;
205 
206     /* get number of PEs to make active, reduce */
207     ierr = MatGetSize( Cmat, &neq, &NN );CHKERRQ(ierr);
208     new_npe = neq/MIN_EQ_PROC; /* hardwire min. number of eq/proc */
209     if( new_npe == 0 || neq < TOP_GRID_LIM ) new_npe = 1;
210     else if (new_npe >= *a_nactive_proc ) new_npe = *a_nactive_proc; /* no change, rare */
211 
212     ierr = PetscMalloc( npe*sizeof(PetscMPIInt), &ranks ); CHKERRQ(ierr);
213     ierr = PetscMalloc( npe*sizeof(PetscInt), &counts ); CHKERRQ(ierr);
214 
215     ierr = MPI_Allgather( &ncrs0, 1, MPIU_INT, counts, 1, MPIU_INT, wcomm ); CHKERRQ(ierr);
216     assert(counts[mype]==ncrs0);
217     /* count real active pes */
218     for( nactive = jj = 0 ; jj < npe ; jj++) {
219       if( counts[jj] != 0 ) {
220 	ranks[nactive++] = jj;
221       }
222     }
223     assert(nactive>=new_npe);
224 
225     PetscPrintf(PETSC_COMM_WORLD,"\t[%d]%s npe (active): %d --> %d. new npe = %d, neq = %d\n",mype,__FUNCT__,*a_nactive_proc,nactive,new_npe,neq);
226     *a_nactive_proc = new_npe; /* output */
227 
228     ierr = MPI_Comm_group( wcomm, &wg ); CHKERRQ(ierr);
229     ierr = MPI_Group_incl( wg, nactive, ranks, &g2 ); CHKERRQ(ierr);
230     ierr = MPI_Comm_create( wcomm, g2, &cm ); CHKERRQ(ierr);
231 
232     if( cm != MPI_COMM_NULL ) {
233       assert(ncrs0 != 0);
234       ierr = PetscCommDuplicate( cm, &new_comm, PETSC_NULL ); CHKERRQ(ierr);
235       ierr = MPI_Comm_free( &cm );                             CHKERRQ(ierr);
236     }
237     else assert(ncrs0 == 0);
238 
239     ierr = MPI_Group_free( &wg );                            CHKERRQ(ierr);
240     ierr = MPI_Group_free( &g2 );                            CHKERRQ(ierr);
241 
242     /* MatPartitioningApply call MatConvert, which is collective */
243 #if defined PETSC_USE_LOG
244     ierr = PetscLogEventBegin(gamg_setup_events[SET12],0,0,0,0);CHKERRQ(ierr);
245 #endif
246     if( a_cbs == 1) {
247       ierr = MatConvert( Cmat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj );   CHKERRQ(ierr);
248     }
249     else{
250       /* make a scalar matrix to partition */
251       Mat tMat;
252       PetscInt ncols;
253       const PetscScalar *vals;
254       const PetscInt *idx;
255       MatInfo info;
256 
257       ierr = MatGetInfo(Cmat,MAT_LOCAL,&info); CHKERRQ(ierr);
258       ncols = (PetscInt)info.nz_used/((ncrs0+1)*a_cbs*a_cbs)+1;
259 
260       ierr = MatCreateMPIAIJ( wcomm, ncrs0, ncrs0,
261                               PETSC_DETERMINE, PETSC_DETERMINE,
262                               2*ncols, PETSC_NULL, ncols, PETSC_NULL,
263                               &tMat );
264       CHKERRQ(ierr);
265 
266       for ( ii = Istart0; ii < Iend0; ii++ ) {
267         PetscInt dest_row = ii/a_cbs;
268         ierr = MatGetRow(Cmat,ii,&ncols,&idx,&vals); CHKERRQ(ierr);
269         for( jj = 0 ; jj < ncols ; jj++ ){
270           PetscInt dest_col = idx[jj]/a_cbs;
271           PetscScalar v = 1.0;
272           ierr = MatSetValues(tMat,1,&dest_row,1,&dest_col,&v,ADD_VALUES); CHKERRQ(ierr);
273         }
274         ierr = MatRestoreRow(Cmat,ii,&ncols,&idx,&vals); CHKERRQ(ierr);
275       }
276       ierr = MatAssemblyBegin(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
277       ierr = MatAssemblyEnd(tMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
278 
279       static int llev = 0;
280       if( llev++ == -1 ) {
281 	PetscViewer viewer; char fname[32];
282 	sprintf(fname,"part_mat_%d.mat",llev);
283 	PetscViewerBinaryOpen(wcomm,fname,FILE_MODE_WRITE,&viewer);
284 	ierr = MatView( tMat, viewer ); CHKERRQ(ierr);
285 	ierr = PetscViewerDestroy( &viewer );
286       }
287 
288       ierr = MatConvert( tMat, MATMPIADJ, MAT_INITIAL_MATRIX, &adj );   CHKERRQ(ierr);
289 
290       ierr = MatDestroy( &tMat );  CHKERRQ(ierr);
291     }
292 
293     if( ncrs0 != 0 ){
294       const PetscInt *is_idx;
295       MatPartitioning  mpart;
296       /* hack to fix global data that pmetis.c uses in 'adj' */
297       for( nactive = jj = 0 ; jj < npe ; jj++ ) {
298 	if( counts[jj] != 0 ) {
299 	  adj->rmap->range[nactive++] = adj->rmap->range[jj];
300 	}
301       }
302       adj->rmap->range[nactive] = adj->rmap->range[npe];
303 
304       ierr = MatPartitioningCreate( new_comm, &mpart ); CHKERRQ(ierr);
305       ierr = MatPartitioningSetAdjacency( mpart, adj ); CHKERRQ(ierr);
306       ierr = MatPartitioningSetFromOptions( mpart );    CHKERRQ(ierr);
307       ierr = MatPartitioningSetNParts( mpart, new_npe );CHKERRQ(ierr);
308       ierr = MatPartitioningApply( mpart, &isnewproc ); CHKERRQ(ierr);
309       ierr = MatPartitioningDestroy( &mpart );          CHKERRQ(ierr);
310 
311       /* collect IS info */
312       ierr = ISGetLocalSize( isnewproc, &is_sz );       CHKERRQ(ierr);
313       ierr = PetscMalloc( a_cbs*is_sz*sizeof(PetscInt), &isnewproc_idx ); CHKERRQ(ierr);
314       ierr = ISGetIndices( isnewproc, &is_idx );        CHKERRQ(ierr);
315       /* spread partitioning across machine - best way ??? */
316       NN = npe/new_npe;
317       for( kk = jj = 0 ; kk < is_sz ; kk++ ){
318         for( ii = 0 ; ii < a_cbs ; ii++, jj++ ) {
319           isnewproc_idx[jj] = is_idx[kk] * NN; /* distribution */
320         }
321       }
322       ierr = ISRestoreIndices( isnewproc, &is_idx );     CHKERRQ(ierr);
323       ierr = ISDestroy( &isnewproc );                    CHKERRQ(ierr);
324       ierr = PetscCommDestroy( &new_comm );              CHKERRQ(ierr);
325 
326       is_sz *= a_cbs;
327     }
328     else{
329       isnewproc_idx = 0;
330       is_sz = 0;
331     }
332     ierr = MatDestroy( &adj );                       CHKERRQ(ierr);
333     ierr = ISCreateGeneral( wcomm, is_sz, isnewproc_idx, PETSC_COPY_VALUES, &isnewproc );
334     if( isnewproc_idx != 0 ) {
335       ierr = PetscFree( isnewproc_idx );  CHKERRQ(ierr);
336     }
337 
338     /*
339      Create an index set from the isnewproc index set to indicate the mapping TO
340      */
341     ierr = ISPartitioningToNumbering( isnewproc, &isnum ); CHKERRQ(ierr);
342     /*
343      Determine how many elements are assigned to each processor
344      */
345     inpe = npe;
346     ierr = ISPartitioningCount( isnewproc, inpe, counts ); CHKERRQ(ierr);
347     ierr = ISDestroy( &isnewproc );                       CHKERRQ(ierr);
348     ncrs_new = counts[mype]/a_cbs;
349     strideNew = ncrs_new*a_ndata_rows;
350 #if defined PETSC_USE_LOG
351     ierr = PetscLogEventEnd(gamg_setup_events[SET12],0,0,0,0);   CHKERRQ(ierr);
352 #endif
353     /* Create a vector to contain the newly ordered element information */
354     ierr = VecCreate( wcomm, &dest_crd );
355     ierr = VecSetSizes( dest_crd, data_sz*ncrs_new, PETSC_DECIDE ); CHKERRQ(ierr);
356     ierr = VecSetFromOptions( dest_crd ); CHKERRQ(ierr); /*funny vector-get global options?*/
357     /*
358       There are 'a_ndata_rows*a_ndata_cols' data items per node, (one can think of the vectors of having
359       a block size of ...).  Note, ISs are expanded into equation space by 'a_cbs'.
360     */
361     ierr = PetscMalloc( (ncrs0*data_sz)*sizeof(PetscInt), &tidx ); CHKERRQ(ierr);
362     ierr = ISGetIndices( isnum, &idx ); CHKERRQ(ierr);
363     for(ii=0,jj=0; ii<ncrs0 ; ii++) {
364       PetscInt id = idx[ii*a_cbs]/a_cbs; /* get node back */
365       for( kk=0; kk<data_sz ; kk++, jj++) tidx[jj] = id*data_sz + kk;
366     }
367     ierr = ISRestoreIndices( isnum, &idx ); CHKERRQ(ierr);
368     ierr = ISCreateGeneral( wcomm, data_sz*ncrs0, tidx, PETSC_COPY_VALUES, &isscat );
369     CHKERRQ(ierr);
370     ierr = PetscFree( tidx );  CHKERRQ(ierr);
371     /*
372       Create a vector to contain the original vertex information for each element
373     */
374     ierr = VecCreateSeq( PETSC_COMM_SELF, data_sz*ncrs0, &src_crd ); CHKERRQ(ierr);
375     for( jj=0; jj<a_ndata_cols ; jj++ ) {
376       for( ii=0 ; ii<ncrs0 ; ii++) {
377 	for( kk=0; kk<a_ndata_rows ; kk++ ) {
378 	  PetscInt ix = ii*a_ndata_rows + kk + jj*stride0, jx = ii*data_sz + kk*a_ndata_cols + jj;
379 	  ierr = VecSetValues( src_crd, 1, &jx, &data[ix], INSERT_VALUES );  CHKERRQ(ierr);
380 	}
381       }
382     }
383     ierr = VecAssemblyBegin(src_crd); CHKERRQ(ierr);
384     ierr = VecAssemblyEnd(src_crd); CHKERRQ(ierr);
385     /*
386       Scatter the element vertex information (still in the original vertex ordering)
387       to the correct processor
388     */
389     ierr = VecScatterCreate( src_crd, PETSC_NULL, dest_crd, isscat, &vecscat);
390     CHKERRQ(ierr);
391     ierr = ISDestroy( &isscat );       CHKERRQ(ierr);
392     ierr = VecScatterBegin(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
393     ierr = VecScatterEnd(vecscat,src_crd,dest_crd,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
394     ierr = VecScatterDestroy( &vecscat );       CHKERRQ(ierr);
395     ierr = VecDestroy( &src_crd );       CHKERRQ(ierr);
396     /*
397       Put the element vertex data into a new allocation of the gdata->ele
398     */
399     ierr = PetscFree( *a_coarse_data );    CHKERRQ(ierr);
400     ierr = PetscMalloc( data_sz*ncrs_new*sizeof(PetscReal), a_coarse_data );    CHKERRQ(ierr);
401 
402     ierr = VecGetArray( dest_crd, &array );    CHKERRQ(ierr);
403     data = *a_coarse_data;
404     for( jj=0; jj<a_ndata_cols ; jj++ ) {
405       for( ii=0 ; ii<ncrs_new ; ii++) {
406 	for( kk=0; kk<a_ndata_rows ; kk++ ) {
407 	  PetscInt ix = ii*a_ndata_rows + kk + jj*strideNew, jx = ii*data_sz + kk*a_ndata_cols + jj;
408 	  data[ix] = PetscRealPart(array[jx]);
409 	  array[jx] = 1.e300;
410 	}
411       }
412     }
413     ierr = VecRestoreArray( dest_crd, &array );    CHKERRQ(ierr);
414     ierr = VecDestroy( &dest_crd );    CHKERRQ(ierr);
415 
416     /*
417       Invert for MatGetSubMatrix
418     */
419     ierr = ISInvertPermutation( isnum, ncrs_new*a_cbs, &new_indices ); CHKERRQ(ierr);
420     ierr = ISSort( new_indices ); CHKERRQ(ierr); /* is this needed? */
421     ierr = ISDestroy( &isnum ); CHKERRQ(ierr);
422     /* A_crs output */
423     ierr = MatGetSubMatrix( Cmat, new_indices, new_indices, MAT_INITIAL_MATRIX, a_Amat_crs );
424     CHKERRQ(ierr);
425 
426     ierr = MatDestroy( &Cmat ); CHKERRQ(ierr);
427     Cmat = *a_Amat_crs; /* output */
428     ierr = MatSetBlockSize( Cmat, a_cbs );      CHKERRQ(ierr);
429 
430     /* prolongator */
431     ierr = MatGetOwnershipRange( Pold, &Istart, &Iend );    CHKERRQ(ierr);
432     {
433       IS findices;
434       ierr = ISCreateStride(wcomm,Iend-Istart,Istart,1,&findices);   CHKERRQ(ierr);
435       ierr = MatGetSubMatrix( Pold, findices, new_indices, MAT_INITIAL_MATRIX, &Pnew );
436       CHKERRQ(ierr);
437       ierr = ISDestroy( &findices ); CHKERRQ(ierr);
438     }
439     ierr = MatDestroy( a_P_inout ); CHKERRQ(ierr);
440     *a_P_inout = Pnew; /* output */
441 
442     ierr = ISDestroy( &new_indices ); CHKERRQ(ierr);
443     ierr = PetscFree( counts );  CHKERRQ(ierr);
444     ierr = PetscFree( ranks );  CHKERRQ(ierr);
445   }
446 
447   PetscFunctionReturn(0);
448 }
449 
450 /* -------------------------------------------------------------------------- */
451 /*
452    PCSetUp_GAMG - Prepares for the use of the GAMG preconditioner
453                     by setting data structures and options.
454 
455    Input Parameter:
456 .  pc - the preconditioner context
457 
458    Application Interface Routine: PCSetUp()
459 
460    Notes:
461    The interface routine PCSetUp() is not usually called directly by
462    the user, but instead is called by PCApply() if necessary.
463 */
464 #undef __FUNCT__
465 #define __FUNCT__ "PCSetUp_GAMG"
466 PetscErrorCode PCSetUp_GAMG( PC a_pc )
467 {
468   PetscErrorCode  ierr;
469   PC_MG           *mg = (PC_MG*)a_pc->data;
470   PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx;
471   Mat              Amat = a_pc->mat, Pmat = a_pc->pmat;
472   PetscInt         fine_level, level, level1, M, N, bs, nloc, lidx, Istart, Iend;
473   MPI_Comm         wcomm = ((PetscObject)a_pc)->comm;
474   PetscMPIInt      mype,npe,nactivepe;
475   PetscBool        isOK;
476   Mat              Aarr[GAMG_MAXLEVELS], Parr[GAMG_MAXLEVELS];
477   PetscReal       *coarse_data = 0, *data, emaxs[GAMG_MAXLEVELS];
478   MatInfo          info;
479 
480   PetscFunctionBegin;
481   if( a_pc->setupcalled ) {
482     /* no state data in GAMG to destroy */
483     ierr = PCReset_MG( a_pc ); CHKERRQ(ierr);
484   }
485   ierr = MPI_Comm_rank(wcomm,&mype);CHKERRQ(ierr);
486   ierr = MPI_Comm_size(wcomm,&npe);CHKERRQ(ierr);
487   /* GAMG requires input of fine-grid matrix. It determines nlevels. */
488   ierr = MatGetBlockSize( Amat, &bs ); CHKERRQ(ierr);
489   ierr = MatGetSize( Amat, &M, &N );CHKERRQ(ierr);
490   ierr = MatGetOwnershipRange( Amat, &Istart, &Iend ); CHKERRQ(ierr);
491   nloc = (Iend-Istart)/bs; assert((Iend-Istart)%bs == 0);
492 
493   /* get data of not around */
494   if( pc_gamg->m_data == 0 && nloc > 0 ) {
495     ierr  = PCSetCoordinates_GAMG( a_pc, -1, 0 );    CHKERRQ( ierr );
496   }
497   data = pc_gamg->m_data;
498 
499   /* Get A_i and R_i */
500   ierr = MatGetInfo(Amat,MAT_GLOBAL_SUM,&info); CHKERRQ(ierr);
501   PetscPrintf(PETSC_COMM_WORLD,"\t[%d]%s level %d N=%ld, n data rows=%d, n data cols=%d, nnz/row (ave)=%d, np=%d\n",
502 	      mype,__FUNCT__,0,(long long int)N,(int)pc_gamg->m_data_rows,(int)pc_gamg->m_data_cols,
503 	      (int)(info.nz_used/(PetscReal)N),(int)npe);
504   for ( level=0, Aarr[0] = Pmat, nactivepe = npe; /* hard wired stopping logic */
505         level < GAMG_MAXLEVELS-1 && (level==0 || M>TOP_GRID_LIM) && (npe==1 || nactivepe>1);
506         level++ ){
507     level1 = level + 1;
508 #if (defined PETSC_USE_LOG && defined GAMG_STAGES)
509     ierr = PetscLogStagePush(gamg_stages[level]); CHKERRQ( ierr );
510 #endif
511 #if defined PETSC_USE_LOG
512     ierr = PetscLogEventBegin(gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
513 #endif
514     ierr = createProlongation(Aarr[level], data, pc_gamg->m_dim, pc_gamg->m_data_cols, pc_gamg->m_useSA,
515                               level, &bs, &Parr[level1], &coarse_data, &isOK, &emaxs[level] );
516     CHKERRQ(ierr);
517     ierr = PetscFree( data ); CHKERRQ( ierr );
518 #if defined PETSC_USE_LOG
519     ierr = PetscLogEventEnd(gamg_setup_events[SET1],0,0,0,0);CHKERRQ(ierr);
520     #endif
521     if(level==0) Aarr[0] = Amat; /* use Pmat for finest level setup, but use mat for solver */
522 
523     if( isOK ) {
524 #if defined PETSC_USE_LOG
525       ierr = PetscLogEventBegin(gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
526 #endif
527       ierr = partitionLevel( Aarr[level], pc_gamg->m_useSA ? bs : 1, pc_gamg->m_data_cols, bs,
528                              &Parr[level1], &coarse_data, &nactivepe, &Aarr[level1] );
529       CHKERRQ(ierr);
530 #if defined PETSC_USE_LOG
531       ierr = PetscLogEventEnd(gamg_setup_events[SET2],0,0,0,0);CHKERRQ(ierr);
532 #endif
533       ierr = MatGetSize( Aarr[level1], &M, &N );CHKERRQ(ierr);
534       ierr = MatGetInfo(Aarr[level1],MAT_GLOBAL_SUM,&info); CHKERRQ(ierr);
535       PetscPrintf(PETSC_COMM_WORLD,"\t\t[%d]%s %d) N=%ld, bs=%d, n data cols=%d, nnz/row (ave)=%d, %d active pes\n",
536 		  mype,__FUNCT__,(int)level1,(long long int)N,(int)bs,(int)pc_gamg->m_data_cols,
537 		  (int)(info.nz_used/(PetscReal)N),(int)nactivepe);
538       /* coarse grids with SA can have zero row/cols from singleton aggregates */
539       /* aggregation method can probably gaurrentee this does not happen! - be safe for now */
540 
541       if( PETSC_TRUE ){
542         Vec diag; PetscScalar *data_arr,v; PetscInt Istart,Iend,kk,nloceq,id;
543         v = 1.e-10; /* LU factor has hard wired numbers for small diags so this needs to match (yuk) */
544         ierr = MatGetOwnershipRange(Aarr[level1], &Istart, &Iend); CHKERRQ(ierr);
545         nloceq = Iend-Istart;
546         ierr = MatGetVecs( Aarr[level1], &diag, 0 );    CHKERRQ(ierr);
547         ierr = MatGetDiagonal( Aarr[level1], diag );    CHKERRQ(ierr);
548         ierr = VecGetArray( diag, &data_arr );   CHKERRQ(ierr);
549         for(kk=0;kk<nloceq;kk++){
550           if(data_arr[kk]==0.0) {
551             id = kk + Istart;
552             ierr = MatSetValues(Aarr[level1],1,&id,1,&id,&v,INSERT_VALUES);
553             CHKERRQ(ierr);
554             PetscPrintf(PETSC_COMM_SELF,"\t[%d]%s warning: added diag to zero (%d) on level %d \n",mype,__FUNCT__,id,level);
555           }
556         }
557         ierr = VecRestoreArray( diag, &data_arr ); CHKERRQ(ierr);
558         ierr = VecDestroy( &diag );                CHKERRQ(ierr);
559         ierr = MatAssemblyBegin(Aarr[level1],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
560         ierr = MatAssemblyEnd(Aarr[level1],MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
561       }
562     }
563     else{
564       coarse_data = 0;
565       break;
566     }
567     data = coarse_data;
568 
569 #if (defined PETSC_USE_LOG && defined GAMG_STAGES)
570     ierr = PetscLogStagePop(); CHKERRQ( ierr );
571 #endif
572   }
573   if( coarse_data ) {
574     ierr = PetscFree( coarse_data ); CHKERRQ( ierr );
575   }
576   PetscPrintf(PETSC_COMM_WORLD,"\t[%d]%s %d levels\n",0,__FUNCT__,level + 1);
577   pc_gamg->m_data = 0; /* destroyed coordinate data */
578   pc_gamg->m_Nlevels = level + 1;
579   fine_level = level;
580   ierr = PCMGSetLevels(a_pc,pc_gamg->m_Nlevels,PETSC_NULL);CHKERRQ(ierr);
581 
582   /* set default smoothers */
583   for ( lidx=1, level = pc_gamg->m_Nlevels-2;
584         lidx <= fine_level;
585         lidx++, level--) {
586     PetscReal emax, emin;
587     KSP smoother; PC subpc;
588     ierr = PCMGGetSmoother( a_pc, lidx, &smoother ); CHKERRQ(ierr);
589     ierr = KSPSetType( smoother, KSPCHEBYCHEV );CHKERRQ(ierr);
590     if( emaxs[level] > 0.0 ) emax=emaxs[level];
591     else{ /* eigen estimate 'emax' */
592       KSP eksp; Mat Lmat = Aarr[level];
593       Vec bb, xx; PC pc;
594 
595       ierr = MatGetVecs( Lmat, &bb, 0 );         CHKERRQ(ierr);
596       ierr = MatGetVecs( Lmat, &xx, 0 );         CHKERRQ(ierr);
597       {
598 	PetscRandom    rctx;
599 	ierr = PetscRandomCreate(wcomm,&rctx);CHKERRQ(ierr);
600 	ierr = PetscRandomSetFromOptions(rctx);CHKERRQ(ierr);
601 	ierr = VecSetRandom(bb,rctx);CHKERRQ(ierr);
602 	ierr = PetscRandomDestroy( &rctx ); CHKERRQ(ierr);
603       }
604       ierr = KSPCreate(wcomm,&eksp);CHKERRQ(ierr);
605       ierr = KSPSetType( eksp, KSPCG );                      CHKERRQ(ierr);
606       ierr = KSPSetInitialGuessNonzero( eksp, PETSC_FALSE ); CHKERRQ(ierr);
607       ierr = KSPSetOperators( eksp, Lmat, Lmat, DIFFERENT_NONZERO_PATTERN ); CHKERRQ( ierr );
608       ierr = KSPGetPC( eksp, &pc );CHKERRQ( ierr );
609       ierr = PCSetType( pc, PCPBJACOBI ); CHKERRQ(ierr); /* should be same as above */
610       ierr = KSPSetTolerances( eksp, PETSC_DEFAULT, PETSC_DEFAULT, PETSC_DEFAULT, 10 );
611       CHKERRQ(ierr);
612       //ierr = KSPSetConvergenceTest( eksp, KSPSkipConverged, 0, 0 ); CHKERRQ(ierr);
613       ierr = KSPSetNormType( eksp, KSP_NORM_NONE );                 CHKERRQ(ierr);
614 
615       ierr = KSPSetComputeSingularValues( eksp,PETSC_TRUE ); CHKERRQ(ierr);
616       ierr = KSPSolve( eksp, bb, xx ); CHKERRQ(ierr);
617       ierr = KSPComputeExtremeSingularValues( eksp, &emax, &emin ); CHKERRQ(ierr);
618       ierr = VecDestroy( &xx );       CHKERRQ(ierr);
619       ierr = VecDestroy( &bb );       CHKERRQ(ierr);
620       ierr = KSPDestroy( &eksp );       CHKERRQ(ierr);
621       PetscPrintf(PETSC_COMM_WORLD,"\t\t\t%s max eigen=%e min=%e PC=%s\n",__FUNCT__,emax,emin,PETSC_GAMG_SMOOTHER);
622     }
623     {
624       PetscInt N1, N0, tt;
625       ierr = MatGetSize( Aarr[level], &N1, &tt );         CHKERRQ(ierr);
626       ierr = MatGetSize( Aarr[level+1], &N0, &tt );       CHKERRQ(ierr);
627       emin = 1.*emax/((PetscReal)N1/(PetscReal)N0); /* this should be about the coarsening rate */
628       emax *= 1.05;
629 
630     }
631 
632     ierr = KSPSetOperators( smoother, Aarr[level], Aarr[level], DIFFERENT_NONZERO_PATTERN );
633     ierr = KSPChebychevSetEigenvalues( smoother, emax, emin );CHKERRQ(ierr);
634     /* ierr = KSPSetTolerances(smoother,PETSC_DEFAULT,PETSC_DEFAULT,PETSC_DEFAULT,2); CHKERRQ(ierr); */
635     ierr = KSPGetPC( smoother, &subpc ); CHKERRQ(ierr);
636     ierr = PCSetType( subpc, PETSC_GAMG_SMOOTHER ); CHKERRQ(ierr);
637     ierr = KSPSetNormType( smoother, KSP_NORM_NONE ); CHKERRQ(ierr);
638   }
639   {
640     KSP smoother; /* coarse grid */
641     Mat Lmat = Aarr[pc_gamg->m_Nlevels-1];
642     ierr = PCMGGetSmoother( a_pc, 0, &smoother ); CHKERRQ(ierr);
643     ierr = KSPSetOperators( smoother, Lmat, Lmat, DIFFERENT_NONZERO_PATTERN );
644     CHKERRQ(ierr);
645     ierr = KSPSetNormType( smoother, KSP_NORM_NONE ); CHKERRQ(ierr);
646   }
647 
648   /* should be called in PCSetFromOptions_GAMG(), but cannot be called prior to PCMGSetLevels() */
649   ierr = PCSetFromOptions_MG(a_pc); CHKERRQ(ierr);
650   {
651     PetscBool galerkin;
652     ierr = PCMGGetGalerkin( a_pc,  &galerkin); CHKERRQ(ierr);
653     if(galerkin){
654       SETERRQ(wcomm,PETSC_ERR_ARG_WRONG, "GAMG does galerkin manually so it must not be used in PC_MG.");
655     }
656   }
657 
658   /* set interpolation between the levels, clean up */
659   for (lidx=0,level=pc_gamg->m_Nlevels-1;
660        lidx<fine_level;
661        lidx++, level--){
662     ierr = PCMGSetInterpolation( a_pc, lidx+1, Parr[level] );CHKERRQ(ierr);
663     if( !PETSC_TRUE ) {
664       PetscViewer viewer; char fname[32];
665       sprintf(fname,"Pmat_%d.m",(int)level);
666       ierr = PetscViewerASCIIOpen( wcomm, fname, &viewer );  CHKERRQ(ierr);
667       ierr = PetscViewerSetFormat( viewer, PETSC_VIEWER_ASCII_MATLAB);  CHKERRQ(ierr);
668       ierr = MatView( Parr[level], viewer ); CHKERRQ(ierr);
669       ierr = PetscViewerDestroy( &viewer );
670       sprintf(fname,"Amat_%d.m",(int)level);
671       ierr = PetscViewerASCIIOpen( wcomm, fname, &viewer );  CHKERRQ(ierr);
672       ierr = PetscViewerSetFormat( viewer, PETSC_VIEWER_ASCII_MATLAB);  CHKERRQ(ierr);
673       ierr = MatView( Aarr[level], viewer ); CHKERRQ(ierr);
674       ierr = PetscViewerDestroy( &viewer );
675     }
676     ierr = MatDestroy( &Parr[level] );  CHKERRQ(ierr);
677     ierr = MatDestroy( &Aarr[level] );  CHKERRQ(ierr);
678   }
679 
680   /* setupcalled is set to 0 so that MG is setup from scratch */
681   a_pc->setupcalled = 0;
682   ierr = PCSetUp_MG(a_pc);CHKERRQ(ierr);
683 
684   PetscFunctionReturn(0);
685 }
686 
687 /* ------------------------------------------------------------------------- */
688 /*
689    PCDestroy_GAMG - Destroys the private context for the GAMG preconditioner
690    that was created with PCCreate_GAMG().
691 
692    Input Parameter:
693 .  pc - the preconditioner context
694 
695    Application Interface Routine: PCDestroy()
696 */
697 #undef __FUNCT__
698 #define __FUNCT__ "PCDestroy_GAMG"
699 PetscErrorCode PCDestroy_GAMG(PC pc)
700 {
701   PetscErrorCode  ierr;
702   PC_MG           *mg = (PC_MG*)pc->data;
703   PC_GAMG         *pc_gamg= (PC_GAMG*)mg->innerctx;
704 
705   PetscFunctionBegin;
706   ierr = PCReset_GAMG(pc);CHKERRQ(ierr);
707   ierr = PetscFree(pc_gamg);CHKERRQ(ierr);
708   ierr = PCDestroy_MG(pc);CHKERRQ(ierr);
709   PetscFunctionReturn(0);
710 }
711 
712 #undef __FUNCT__
713 #define __FUNCT__ "PCSetFromOptions_GAMG"
714 PetscErrorCode PCSetFromOptions_GAMG(PC pc)
715 {
716   /* PetscErrorCode  ierr; */
717   /* PC_MG           *mg = (PC_MG*)pc->data; */
718   /* PC_GAMG         *pc_gamg = (PC_GAMG*)mg->innerctx; */
719   /* MPI_Comm        comm = ((PetscObject)pc)->comm; */
720 
721   PetscFunctionBegin;
722   PetscFunctionReturn(0);
723 }
724 
725 /* -------------------------------------------------------------------------- */
726 /*
727  PCCreate_GAMG - Creates a GAMG preconditioner context, PC_GAMG
728 
729    Input Parameter:
730 .  pc - the preconditioner context
731 
732    Application Interface Routine: PCCreate()
733 
734   */
735  /* MC
736      PCGAMG - Use algebraic multigrid preconditioning. This preconditioner requires you provide
737        fine grid discretization matrix and coordinates on the fine grid.
738 
739    Options Database Key:
740    Multigrid options(inherited)
741 +  -pc_mg_cycles <1>: 1 for V cycle, 2 for W-cycle (MGSetCycles)
742 .  -pc_mg_smoothup <1>: Number of post-smoothing steps (MGSetNumberSmoothUp)
743 .  -pc_mg_smoothdown <1>: Number of pre-smoothing steps (MGSetNumberSmoothDown)
744    -pc_mg_type <multiplicative>: (one of) additive multiplicative full cascade kascade
745    GAMG options:
746 
747    Level: intermediate
748   Concepts: multigrid
749 
750 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC, PCMGType,
751            PCMGSetLevels(), PCMGGetLevels(), PCMGSetType(), MPSetCycles(), PCMGSetNumberSmoothDown(),
752            PCMGSetNumberSmoothUp(), PCMGGetCoarseSolve(), PCMGSetResidual(), PCMGSetInterpolation(),
753            PCMGSetRestriction(), PCMGGetSmoother(), PCMGGetSmootherUp(), PCMGGetSmootherDown(),
754            PCMGSetCyclesOnLevel(), PCMGSetRhs(), PCMGSetX(), PCMGSetR()
755 M */
756 
757 EXTERN_C_BEGIN
758 #undef __FUNCT__
759 #define __FUNCT__ "PCCreate_GAMG"
760 PetscErrorCode  PCCreate_GAMG(PC pc)
761 {
762   PetscErrorCode  ierr;
763   PC_GAMG         *pc_gamg;
764   PC_MG           *mg;
765   PetscClassId     cookie;
766 
767   PetscFunctionBegin;
768   /* PCGAMG is an inherited class of PCMG. Initialize pc as PCMG */
769   ierr = PCSetType(pc,PCMG);CHKERRQ(ierr); /* calls PCCreate_MG() and MGCreate_Private() */
770   ierr = PetscObjectChangeTypeName((PetscObject)pc,PCGAMG);CHKERRQ(ierr);
771 
772   /* create a supporting struct and attach it to pc */
773   ierr = PetscNewLog(pc,PC_GAMG,&pc_gamg);CHKERRQ(ierr);
774   mg = (PC_MG*)pc->data;
775   mg->innerctx = pc_gamg;
776 
777   pc_gamg->m_Nlevels    = -1;
778 
779   /* overwrite the pointers of PCMG by the functions of PCGAMG */
780   pc->ops->setfromoptions = PCSetFromOptions_GAMG;
781   pc->ops->setup          = PCSetUp_GAMG;
782   pc->ops->reset          = PCReset_GAMG;
783   pc->ops->destroy        = PCDestroy_GAMG;
784 
785   ierr = PetscObjectComposeFunctionDynamic( (PetscObject)pc,
786 					    "PCSetCoordinates_C",
787 					    "PCSetCoordinates_GAMG",
788 					    PCSetCoordinates_GAMG);CHKERRQ(ierr);
789 #if defined PETSC_USE_LOG
790   static int count = 0;
791   if( count++ == 0 ) {
792     PetscClassIdRegister("GAMG Setup",&cookie);
793     PetscLogEventRegister("GAMG: createProl", cookie, &gamg_setup_events[SET1]);
794     PetscLogEventRegister(" make graph", cookie, &gamg_setup_events[SET3]);
795     PetscLogEventRegister(" MIS/Agg", cookie, &gamg_setup_events[SET4]);
796     PetscLogEventRegister("  geo: growSupp", cookie, &gamg_setup_events[SET5]);
797     PetscLogEventRegister("  geo: triangle", cookie, &gamg_setup_events[SET6]);
798     PetscLogEventRegister("   search & set", cookie, &gamg_setup_events[FIND_V]);
799     PetscLogEventRegister("  SA: init", cookie, &gamg_setup_events[SET7]);
800     /* PetscLogEventRegister("  SA: frmProl0", cookie, &gamg_setup_events[SET8]); */
801     PetscLogEventRegister("  SA: smooth", cookie, &gamg_setup_events[SET9]);
802     PetscLogEventRegister("GAMG: partLevel", cookie, &gamg_setup_events[SET2]);
803     PetscLogEventRegister(" PL repartition", cookie, &gamg_setup_events[SET12]);
804     /* PetscLogEventRegister(" PL move data", cookie, &gamg_setup_events[SET13]); */
805     /* PetscLogEventRegister("GAMG: fix", cookie, &gamg_setup_events[SET10]); */
806     /* PetscLogEventRegister("GAMG: set levels", cookie, &gamg_setup_events[SET11]); */
807 
808     /* create timer stages */
809 #if defined GAMG_STAGES
810     {
811       char str[32];
812       sprintf(str,"MG Level %d (finest)",0);
813       PetscLogStageRegister(str, &gamg_stages[0]);
814       PetscInt lidx;
815       for (lidx=1;lidx<9;lidx++){
816 	sprintf(str,"MG Level %d",lidx);
817 	PetscLogStageRegister(str, &gamg_stages[lidx]);
818       }
819     }
820 #endif
821   }
822 #endif
823   PetscFunctionReturn(0);
824 }
825 EXTERN_C_END
826