xref: /petsc/src/ksp/pc/impls/tfs/xxt.c (revision a6dfd86ebdf75fa024070af26d51b62fd16650a3)
1 
2 /*************************************xxt.c************************************
3 Module Name: xxt
4 Module Info:
5 
6 author:  Henry M. Tufo III
7 e-mail:  hmt@asci.uchicago.edu
8 contact:
9 +--------------------------------+--------------------------------+
10 |MCS Division - Building 221     |Department of Computer Science  |
11 |Argonne National Laboratory     |Ryerson 152                     |
12 |9700 S. Cass Avenue             |The University of Chicago       |
13 |Argonne, IL  60439              |Chicago, IL  60637              |
14 |(630) 252-5354/5986 ph/fx       |(773) 702-6019/8487 ph/fx       |
15 +--------------------------------+--------------------------------+
16 
17 Last Modification: 3.20.01
18 **************************************xxt.c***********************************/
19 #include <../src/ksp/pc/impls/tfs/tfs.h>
20 
21 #define LEFT  -1
22 #define RIGHT  1
23 #define BOTH   0
24 
25 typedef struct xxt_solver_info {
26   PetscInt n, m, n_global, m_global;
27   PetscInt nnz, max_nnz, msg_buf_sz;
28   PetscInt *nsep, *lnsep, *fo, nfo, *stages;
29   PetscInt *col_sz, *col_indices;
30   PetscScalar **col_vals, *x, *solve_uu, *solve_w;
31   PetscInt nsolves;
32   PetscScalar tot_solve_time;
33 } xxt_info;
34 
35 typedef struct matvec_info {
36   PetscInt n, m, n_global, m_global;
37   PetscInt *local2global;
38   PCTFS_gs_ADT PCTFS_gs_handle;
39   PetscErrorCode (*matvec)(struct matvec_info*,PetscScalar*,PetscScalar*);
40   void *grid_data;
41 } mv_info;
42 
43 struct xxt_CDT{
44   PetscInt id;
45   PetscInt ns;
46   PetscInt level;
47   xxt_info *info;
48   mv_info  *mvi;
49 };
50 
51 static PetscInt n_xxt=0;
52 static PetscInt n_xxt_handles=0;
53 
54 /* prototypes */
55 static PetscErrorCode do_xxt_solve(xxt_ADT xxt_handle, PetscScalar *rhs);
56 static PetscErrorCode check_handle(xxt_ADT xxt_handle);
57 static PetscErrorCode det_separators(xxt_ADT xxt_handle);
58 static PetscErrorCode do_matvec(mv_info *A, PetscScalar *v, PetscScalar *u);
59 static PetscInt xxt_generate(xxt_ADT xxt_handle);
60 static PetscInt do_xxt_factor(xxt_ADT xxt_handle);
61 static mv_info *set_mvi(PetscInt *local2global, PetscInt n, PetscInt m, void *matvec, void *grid_data);
62 
63 /**************************************xxt.c***********************************/
64 xxt_ADT XXT_new(void)
65 {
66   xxt_ADT xxt_handle;
67 
68   /* rolling count on n_xxt ... pot. problem here */
69   n_xxt_handles++;
70   xxt_handle       = (xxt_ADT)malloc(sizeof(struct xxt_CDT));
71   xxt_handle->id   = ++n_xxt;
72   xxt_handle->info = NULL; xxt_handle->mvi  = NULL;
73 
74   return(xxt_handle);
75 }
76 
77 /**************************************xxt.c***********************************/
78 PetscInt XXT_factor(xxt_ADT xxt_handle, /* prev. allocated xxt  handle */
79            PetscInt *local2global,  /* global column mapping       */
80            PetscInt n,              /* local num rows              */
81            PetscInt m,              /* local num cols              */
82            void *matvec,       /* b_loc=A_local.x_loc         */
83            void *grid_data     /* grid data for matvec        */
84            )
85 {
86   PCTFS_comm_init();
87   check_handle(xxt_handle);
88 
89   /* only 2^k for now and all nodes participating */
90   if ((1<<(xxt_handle->level=PCTFS_i_log2_num_nodes))!=PCTFS_num_nodes) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"only 2^k for now and MPI_COMM_WORLD!!! %D != %D\n",1<<PCTFS_i_log2_num_nodes,PCTFS_num_nodes);
91 
92   /* space for X info */
93   xxt_handle->info = (xxt_info*)malloc(sizeof(xxt_info));
94 
95   /* set up matvec handles */
96   xxt_handle->mvi  = set_mvi(local2global, n, m, matvec, grid_data);
97 
98   /* matrix is assumed to be of full rank */
99   /* LATER we can reset to indicate rank def. */
100   xxt_handle->ns=0;
101 
102   /* determine separators and generate firing order - NB xxt info set here */
103   det_separators(xxt_handle);
104 
105   return(do_xxt_factor(xxt_handle));
106 }
107 
108 /**************************************xxt.c***********************************/
109 PetscInt XXT_solve(xxt_ADT xxt_handle, PetscScalar *x, PetscScalar *b)
110 {
111 
112   PCTFS_comm_init();
113   check_handle(xxt_handle);
114 
115   /* need to copy b into x? */
116   if (b) {PCTFS_rvec_copy(x,b,xxt_handle->mvi->n);}
117   do_xxt_solve(xxt_handle,x);
118 
119   return(0);
120 }
121 
122 /**************************************xxt.c***********************************/
123 PetscInt XXT_free(xxt_ADT xxt_handle)
124 {
125 
126   PCTFS_comm_init();
127   check_handle(xxt_handle);
128   n_xxt_handles--;
129 
130   free(xxt_handle->info->nsep);
131   free(xxt_handle->info->lnsep);
132   free(xxt_handle->info->fo);
133   free(xxt_handle->info->stages);
134   free(xxt_handle->info->solve_uu);
135   free(xxt_handle->info->solve_w);
136   free(xxt_handle->info->x);
137   free(xxt_handle->info->col_vals);
138   free(xxt_handle->info->col_sz);
139   free(xxt_handle->info->col_indices);
140   free(xxt_handle->info);
141   free(xxt_handle->mvi->local2global);
142    PCTFS_gs_free(xxt_handle->mvi->PCTFS_gs_handle);
143   free(xxt_handle->mvi);
144   free(xxt_handle);
145 
146   /* if the check fails we nuke */
147   /* if NULL pointer passed to free we nuke */
148   /* if the calls to free fail that's not my problem */
149   return(0);
150 }
151 
152 /**************************************xxt.c***********************************/
153 PetscInt XXT_stats(xxt_ADT xxt_handle)
154 {
155   PetscInt       op[] = {NON_UNIFORM,GL_MIN,GL_MAX,GL_ADD,GL_MIN,GL_MAX,GL_ADD,GL_MIN,GL_MAX,GL_ADD};
156   PetscInt       fop[] = {NON_UNIFORM,GL_MIN,GL_MAX,GL_ADD};
157   PetscInt       vals[9],  work[9];
158   PetscScalar    fvals[3], fwork[3];
159   PetscErrorCode ierr;
160 
161   PCTFS_comm_init();
162   check_handle(xxt_handle);
163 
164   /* if factorization not done there are no stats */
165   if (!xxt_handle->info||!xxt_handle->mvi) {
166     if (!PCTFS_my_id) { ierr = PetscPrintf(PETSC_COMM_WORLD,"XXT_stats() :: no stats available!\n");CHKERRQ(ierr); }
167     return 1;
168   }
169 
170   vals[0]=vals[1]=vals[2]=xxt_handle->info->nnz;
171   vals[3]=vals[4]=vals[5]=xxt_handle->mvi->n;
172   vals[6]=vals[7]=vals[8]=xxt_handle->info->msg_buf_sz;
173   PCTFS_giop(vals,work,sizeof(op)/sizeof(op[0])-1,op);
174 
175   fvals[0]=fvals[1]=fvals[2]
176     =xxt_handle->info->tot_solve_time/xxt_handle->info->nsolves++;
177   PCTFS_grop(fvals,fwork,sizeof(fop)/sizeof(fop[0])-1,fop);
178 
179   if (!PCTFS_my_id) {
180     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_nnz=%D\n",PCTFS_my_id,vals[0]);CHKERRQ(ierr);
181     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_nnz=%D\n",PCTFS_my_id,vals[1]);CHKERRQ(ierr);
182     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_nnz=%g\n",PCTFS_my_id,1.0*vals[2]/PCTFS_num_nodes);CHKERRQ(ierr);
183     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: tot   xxt_nnz=%D\n",PCTFS_my_id,vals[2]);CHKERRQ(ierr);
184     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: xxt   C(2d)  =%g\n",PCTFS_my_id,vals[2]/(pow(1.0*vals[5],1.5)));CHKERRQ(ierr);
185     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: xxt   C(3d)  =%g\n",PCTFS_my_id,vals[2]/(pow(1.0*vals[5],1.6667)));CHKERRQ(ierr);
186     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_n  =%D\n",PCTFS_my_id,vals[3]);CHKERRQ(ierr);
187     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_n  =%D\n",PCTFS_my_id,vals[4]);CHKERRQ(ierr);
188     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_n  =%g\n",PCTFS_my_id,1.0*vals[5]/PCTFS_num_nodes);CHKERRQ(ierr);
189     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: tot   xxt_n  =%D\n",PCTFS_my_id,vals[5]);CHKERRQ(ierr);
190     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_buf=%D\n",PCTFS_my_id,vals[6]);CHKERRQ(ierr);
191     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_buf=%D\n",PCTFS_my_id,vals[7]);CHKERRQ(ierr);
192     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_buf=%g\n",PCTFS_my_id,1.0*vals[8]/PCTFS_num_nodes);CHKERRQ(ierr);
193     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_slv=%g\n",PCTFS_my_id,fvals[0]);CHKERRQ(ierr);
194     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_slv=%g\n",PCTFS_my_id,fvals[1]);CHKERRQ(ierr);
195     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_slv=%g\n",PCTFS_my_id,fvals[2]/PCTFS_num_nodes);CHKERRQ(ierr);
196   }
197 
198   return(0);
199 }
200 
201 /*************************************xxt.c************************************
202 
203 Description: get A_local, local portion of global coarse matrix which
204 is a row dist. nxm matrix w/ n<m.
205    o my_ml holds address of ML struct associated w/A_local and coarse grid
206    o local2global holds global number of column i (i=0,...,m-1)
207    o local2global holds global number of row    i (i=0,...,n-1)
208    o mylocmatvec performs A_local . vec_local (note that gs is performed using
209    PCTFS_gs_init/gop).
210 
211 mylocmatvec = my_ml->Amat[grid_tag].matvec->external;
212 mylocmatvec (void :: void *data, double *in, double *out)
213 **************************************xxt.c***********************************/
214 static PetscInt do_xxt_factor(xxt_ADT xxt_handle)
215 {
216   return xxt_generate(xxt_handle);
217 }
218 
219 /**************************************xxt.c***********************************/
220 static PetscInt xxt_generate(xxt_ADT xxt_handle)
221 {
222   PetscInt i,j,k,idex;
223   PetscInt dim, col;
224   PetscScalar *u, *uu, *v, *z, *w, alpha, alpha_w;
225   PetscInt *segs;
226   PetscInt op[] = {GL_ADD,0};
227   PetscInt off, len;
228   PetscScalar *x_ptr;
229   PetscInt *iptr, flag;
230   PetscInt start=0, end, work;
231   PetscInt op2[] = {GL_MIN,0};
232   PCTFS_gs_ADT PCTFS_gs_handle;
233   PetscInt *nsep, *lnsep, *fo;
234   PetscInt a_n=xxt_handle->mvi->n;
235   PetscInt a_m=xxt_handle->mvi->m;
236   PetscInt *a_local2global=xxt_handle->mvi->local2global;
237   PetscInt level;
238   PetscInt xxt_nnz=0, xxt_max_nnz=0;
239   PetscInt n, m;
240   PetscInt *col_sz, *col_indices, *stages;
241   PetscScalar **col_vals, *x;
242   PetscInt n_global;
243   PetscInt xxt_zero_nnz=0;
244   PetscInt xxt_zero_nnz_0=0;
245   PetscBLASInt i1 = 1,dlen;
246   PetscScalar dm1 = -1.0;
247   PetscErrorCode ierr;
248 
249   n=xxt_handle->mvi->n;
250   nsep=xxt_handle->info->nsep;
251   lnsep=xxt_handle->info->lnsep;
252   fo=xxt_handle->info->fo;
253   end=lnsep[0];
254   level=xxt_handle->level;
255   PCTFS_gs_handle=xxt_handle->mvi->PCTFS_gs_handle;
256 
257   /* is there a null space? */
258   /* LATER add in ability to detect null space by checking alpha */
259   for (i=0, j=0; i<=level; i++)
260     {j+=nsep[i];}
261 
262   m = j-xxt_handle->ns;
263   if (m!=j) {
264     ierr = PetscPrintf(PETSC_COMM_WORLD,"xxt_generate() :: null space exists %D %D %D\n",m,j,xxt_handle->ns);CHKERRQ(ierr);
265   }
266 
267   /* get and initialize storage for x local         */
268   /* note that x local is nxm and stored by columns */
269   col_sz = (PetscInt*) malloc(m*sizeof(PetscInt));
270   col_indices = (PetscInt*) malloc((2*m+1)*sizeof(PetscInt));
271   col_vals = (PetscScalar **) malloc(m*sizeof(PetscScalar *));
272   for (i=j=0; i<m; i++, j+=2) {
273     col_indices[j]=col_indices[j+1]=col_sz[i]=-1;
274     col_vals[i] = NULL;
275   }
276   col_indices[j]=-1;
277 
278   /* size of separators for each sub-hc working from bottom of tree to top */
279   /* this looks like nsep[]=segments */
280   stages = (PetscInt*) malloc((level+1)*sizeof(PetscInt));
281   segs   = (PetscInt*) malloc((level+1)*sizeof(PetscInt));
282   PCTFS_ivec_zero(stages,level+1);
283   PCTFS_ivec_copy(segs,nsep,level+1);
284   for (i=0; i<level; i++) { segs[i+1] += segs[i]; }
285   stages[0] = segs[0];
286 
287   /* temporary vectors  */
288   u  = (PetscScalar *) malloc(n*sizeof(PetscScalar));
289   z  = (PetscScalar *) malloc(n*sizeof(PetscScalar));
290   v  = (PetscScalar *) malloc(a_m*sizeof(PetscScalar));
291   uu = (PetscScalar *) malloc(m*sizeof(PetscScalar));
292   w  = (PetscScalar *) malloc(m*sizeof(PetscScalar));
293 
294   /* extra nnz due to replication of vertices across separators */
295   for (i=1, j=0; i<=level; i++) {j+=nsep[i];}
296 
297   /* storage for sparse x values */
298   n_global = xxt_handle->info->n_global;
299   xxt_max_nnz = (PetscInt)(2.5*pow(1.0*n_global,1.6667) + j*n/2)/PCTFS_num_nodes;
300   x = (PetscScalar *) malloc(xxt_max_nnz*sizeof(PetscScalar));
301   xxt_nnz = 0;
302 
303   /* LATER - can embed next sep to fire in gs */
304   /* time to make the donuts - generate X factor */
305   for (dim=i=j=0;i<m;i++)
306   {
307     /* time to move to the next level? */
308     while (i==segs[dim]) {
309       if (dim==level) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"dim about to exceed level\n");
310       stages[dim++]=i;
311       end+=lnsep[dim];
312     }
313     stages[dim]=i;
314 
315     /* which column are we firing? */
316     /* i.e. set v_l */
317     /* use new seps and do global min across hc to determine which one to fire */
318     (start<end) ? (col=fo[start]) : (col=INT_MAX);
319     PCTFS_giop_hc(&col,&work,1,op2,dim);
320 
321     /* shouldn't need this */
322     if (col==INT_MAX) {
323       ierr = PetscInfo(0,"hey ... col==INT_MAX??\n");CHKERRQ(ierr);
324       continue;
325     }
326 
327     /* do I own it? I should */
328     PCTFS_rvec_zero(v ,a_m);
329     if (col==fo[start]) {
330       start++;
331       idex=PCTFS_ivec_linear_search(col, a_local2global, a_n);
332       if (idex!=-1) {
333         v[idex] = 1.0; j++;
334       } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"NOT FOUND!\n");
335     } else {
336       idex=PCTFS_ivec_linear_search(col, a_local2global, a_m);
337       if (idex!=-1)
338         {v[idex] = 1.0;}
339     }
340 
341     /* perform u = A.v_l */
342     PCTFS_rvec_zero(u,n);
343     do_matvec(xxt_handle->mvi,v,u);
344 
345     /* uu =  X^T.u_l (local portion) */
346     /* technically only need to zero out first i entries */
347     /* later turn this into an XXT_solve call ? */
348     PCTFS_rvec_zero(uu,m);
349     x_ptr=x;
350     iptr = col_indices;
351     for (k=0; k<i; k++) {
352       off = *iptr++;
353       len = *iptr++;
354       dlen = PetscBLASIntCast(len);
355       uu[k] = BLASdot_(&dlen,u+off,&i1,x_ptr,&i1);
356       x_ptr+=len;
357     }
358 
359 
360     /* uu = X^T.u_l (comm portion) */
361     PCTFS_ssgl_radd  (uu, w, dim, stages);
362 
363     /* z = X.uu */
364     PCTFS_rvec_zero(z,n);
365     x_ptr=x;
366     iptr = col_indices;
367     for (k=0; k<i; k++) {
368       off = *iptr++;
369       len = *iptr++;
370       dlen = PetscBLASIntCast(len);
371       BLASaxpy_(&dlen,&uu[k],x_ptr,&i1,z+off,&i1);
372       x_ptr+=len;
373     }
374 
375     /* compute v_l = v_l - z */
376     PCTFS_rvec_zero(v+a_n,a_m-a_n);
377     dlen = PetscBLASIntCast(n);
378     BLASaxpy_(&dlen,&dm1,z,&i1,v,&i1);
379 
380     /* compute u_l = A.v_l */
381     if (a_n!=a_m) { PCTFS_gs_gop_hc(PCTFS_gs_handle,v,"+\0",dim); }
382     PCTFS_rvec_zero(u,n);
383     do_matvec(xxt_handle->mvi,v,u);
384 
385     /* compute sqrt(alpha) = sqrt(v_l^T.u_l) - local portion */
386     dlen = PetscBLASIntCast(n);
387     alpha = BLASdot_(&dlen,u,&i1,v,&i1);
388     /* compute sqrt(alpha) = sqrt(v_l^T.u_l) - comm portion */
389     PCTFS_grop_hc(&alpha, &alpha_w, 1, op, dim);
390 
391     alpha = (PetscScalar) PetscSqrtReal((PetscReal)alpha);
392 
393     /* check for small alpha                             */
394     /* LATER use this to detect and determine null space */
395     if (fabs(alpha)<1.0e-14) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"bad alpha! %g\n",alpha);
396 
397     /* compute v_l = v_l/sqrt(alpha) */
398     PCTFS_rvec_scale(v,1.0/alpha,n);
399 
400     /* add newly generated column, v_l, to X */
401     flag = 1;
402     off=len=0;
403     for (k=0; k<n; k++) {
404       if (v[k]!=0.0) {
405         len=k;
406         if (flag) { off=k; flag=0; }
407       }
408     }
409 
410     len -= (off-1);
411 
412     if (len>0) {
413       if ((xxt_nnz+len)>xxt_max_nnz) {
414         ierr = PetscInfo(0,"increasing space for X by 2x!\n");CHKERRQ(ierr);
415         xxt_max_nnz *= 2;
416         x_ptr = (PetscScalar *) malloc(xxt_max_nnz*sizeof(PetscScalar));
417         PCTFS_rvec_copy(x_ptr,x,xxt_nnz);
418         free(x);
419         x = x_ptr;
420         x_ptr+=xxt_nnz;
421       }
422       xxt_nnz += len;
423       PCTFS_rvec_copy(x_ptr,v+off,len);
424 
425       /* keep track of number of zeros */
426       if (dim) {
427         for (k=0; k<len; k++) {
428           if (x_ptr[k]==0.0) { xxt_zero_nnz++; }
429         }
430       } else {
431         for (k=0; k<len; k++) {
432           if (x_ptr[k]==0.0) {xxt_zero_nnz_0++;}
433         }
434       }
435       col_indices[2*i] = off;
436       col_sz[i] = col_indices[2*i+1] = len;
437       col_vals[i] = x_ptr;
438     }
439     else {
440       col_indices[2*i] = 0;
441       col_sz[i] = col_indices[2*i+1] = 0;
442       col_vals[i] = x_ptr;
443     }
444   }
445 
446   /* close off stages for execution phase */
447   while (dim!=level) {
448     stages[dim++]=i;
449     ierr = PetscInfo2(0,"disconnected!!! dim(%D)!=level(%D)\n",dim,level);CHKERRQ(ierr);
450   }
451   stages[dim]=i;
452 
453   xxt_handle->info->n=xxt_handle->mvi->n;
454   xxt_handle->info->m=m;
455   xxt_handle->info->nnz=xxt_nnz;
456   xxt_handle->info->max_nnz=xxt_max_nnz;
457   xxt_handle->info->msg_buf_sz=stages[level]-stages[0];
458   xxt_handle->info->solve_uu = (PetscScalar *) malloc(m*sizeof(PetscScalar));
459   xxt_handle->info->solve_w  = (PetscScalar *) malloc(m*sizeof(PetscScalar));
460   xxt_handle->info->x=x;
461   xxt_handle->info->col_vals=col_vals;
462   xxt_handle->info->col_sz=col_sz;
463   xxt_handle->info->col_indices=col_indices;
464   xxt_handle->info->stages=stages;
465   xxt_handle->info->nsolves=0;
466   xxt_handle->info->tot_solve_time=0.0;
467 
468   free(segs);
469   free(u);
470   free(v);
471   free(uu);
472   free(z);
473   free(w);
474 
475   return(0);
476 }
477 
478 /**************************************xxt.c***********************************/
479 static PetscErrorCode do_xxt_solve(xxt_ADT xxt_handle,  PetscScalar *uc)
480 {
481   PetscInt off, len, *iptr;
482   PetscInt level       =xxt_handle->level;
483   PetscInt n           =xxt_handle->info->n;
484   PetscInt m           =xxt_handle->info->m;
485   PetscInt *stages     =xxt_handle->info->stages;
486   PetscInt *col_indices=xxt_handle->info->col_indices;
487   PetscScalar *x_ptr, *uu_ptr;
488   PetscScalar *solve_uu=xxt_handle->info->solve_uu;
489   PetscScalar *solve_w =xxt_handle->info->solve_w;
490   PetscScalar *x       =xxt_handle->info->x;
491   PetscBLASInt i1 = 1,dlen;
492 
493   PetscFunctionBegin;
494   uu_ptr=solve_uu;
495   PCTFS_rvec_zero(uu_ptr,m);
496 
497   /* x  = X.Y^T.b */
498   /* uu = Y^T.b */
499   for (x_ptr=x,iptr=col_indices; *iptr!=-1; x_ptr+=len) {
500     off=*iptr++; len=*iptr++;
501     dlen = PetscBLASIntCast(len);
502     *uu_ptr++ = BLASdot_(&dlen,uc+off,&i1,x_ptr,&i1);
503   }
504 
505   /* comunication of beta */
506   uu_ptr=solve_uu;
507   if (level) { PCTFS_ssgl_radd(uu_ptr, solve_w, level, stages); }
508 
509   PCTFS_rvec_zero(uc,n);
510 
511   /* x = X.uu */
512   for (x_ptr=x,iptr=col_indices; *iptr!=-1; x_ptr+=len) {
513     off=*iptr++; len=*iptr++;
514     dlen = PetscBLASIntCast(len);
515     BLASaxpy_(&dlen,uu_ptr++,x_ptr,&i1,uc+off,&i1);
516   }
517   PetscFunctionReturn(0);
518 }
519 
520 /**************************************xxt.c***********************************/
521 static PetscErrorCode check_handle(xxt_ADT xxt_handle)
522 {
523   PetscInt vals[2], work[2], op[] = {NON_UNIFORM,GL_MIN,GL_MAX};
524 
525   PetscFunctionBegin;
526   if (!xxt_handle) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"check_handle() :: bad handle :: NULL %D\n",xxt_handle);
527 
528   vals[0]=vals[1]=xxt_handle->id;
529   PCTFS_giop(vals,work,sizeof(op)/sizeof(op[0])-1,op);
530   if ((vals[0]!=vals[1])||(xxt_handle->id<=0)) SETERRQ3(PETSC_COMM_SELF,PETSC_ERR_PLIB,"check_handle() :: bad handle :: id mismatch min/max %D/%D %D\n",vals[0],vals[1], xxt_handle->id);
531   PetscFunctionReturn(0);
532 }
533 
534 /**************************************xxt.c***********************************/
535 static  PetscErrorCode det_separators(xxt_ADT xxt_handle)
536 {
537   PetscInt i, ct, id;
538   PetscInt mask, edge, *iptr;
539   PetscInt *dir, *used;
540   PetscInt sum[4], w[4];
541   PetscScalar rsum[4], rw[4];
542   PetscInt op[] = {GL_ADD,0};
543   PetscScalar *lhs, *rhs;
544   PetscInt *nsep, *lnsep, *fo, nfo=0;
545   PCTFS_gs_ADT PCTFS_gs_handle=xxt_handle->mvi->PCTFS_gs_handle;
546   PetscInt *local2global=xxt_handle->mvi->local2global;
547   PetscInt  n=xxt_handle->mvi->n;
548   PetscInt  m=xxt_handle->mvi->m;
549   PetscInt level=xxt_handle->level;
550   PetscInt shared=0;
551 
552   PetscFunctionBegin;
553   dir  = (PetscInt*)malloc(sizeof(PetscInt)*(level+1));
554   nsep = (PetscInt*)malloc(sizeof(PetscInt)*(level+1));
555   lnsep= (PetscInt*)malloc(sizeof(PetscInt)*(level+1));
556   fo   = (PetscInt*)malloc(sizeof(PetscInt)*(n+1));
557   used = (PetscInt*)malloc(sizeof(PetscInt)*n);
558 
559   PCTFS_ivec_zero(dir  ,level+1);
560   PCTFS_ivec_zero(nsep ,level+1);
561   PCTFS_ivec_zero(lnsep,level+1);
562   PCTFS_ivec_set (fo   ,-1,n+1);
563   PCTFS_ivec_zero(used,n);
564 
565   lhs  = (PetscScalar*)malloc(sizeof(PetscScalar)*m);
566   rhs  = (PetscScalar*)malloc(sizeof(PetscScalar)*m);
567 
568   /* determine the # of unique dof */
569   PCTFS_rvec_zero(lhs,m);
570   PCTFS_rvec_set(lhs,1.0,n);
571   PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",level);
572   PCTFS_rvec_zero(rsum,2);
573   for (ct=i=0;i<n;i++) {
574     if (lhs[i]!=0.0)
575       {rsum[0]+=1.0/lhs[i]; rsum[1]+=lhs[i];}
576   }
577   PCTFS_grop_hc(rsum,rw,2,op,level);
578   rsum[0]+=0.1;
579   rsum[1]+=0.1;
580 
581   if (fabs(rsum[0]-rsum[1])>EPS) { shared=1; }
582 
583   xxt_handle->info->n_global=xxt_handle->info->m_global=(PetscInt) rsum[0];
584   xxt_handle->mvi->n_global =xxt_handle->mvi->m_global =(PetscInt) rsum[0];
585 
586   /* determine separator sets top down */
587   if (shared)
588   {
589     for (iptr=fo+n,id=PCTFS_my_id,mask=PCTFS_num_nodes>>1,edge=level;edge>0;edge--,mask>>=1) {
590 
591       /* set rsh of hc, fire, and collect lhs responses */
592       (id<mask) ? PCTFS_rvec_zero(lhs,m) : PCTFS_rvec_set(lhs,1.0,m);
593       PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",edge);
594 
595       /* set lsh of hc, fire, and collect rhs responses */
596       (id<mask) ? PCTFS_rvec_set(rhs,1.0,m) : PCTFS_rvec_zero(rhs,m);
597       PCTFS_gs_gop_hc(PCTFS_gs_handle,rhs,"+\0",edge);
598 
599       for (i=0;i<n;i++) {
600         if (id< mask) {
601           if (lhs[i]!=0.0) { lhs[i]=1.0; }
602         }
603 
604         if (id>=mask) {
605           if (rhs[i]!=0.0) { rhs[i]=1.0; }
606         }
607       }
608 
609       if (id< mask) { PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",edge-1); }
610       else          { PCTFS_gs_gop_hc(PCTFS_gs_handle,rhs,"+\0",edge-1); }
611 
612       /* count number of dofs I own that have signal and not in sep set */
613       PCTFS_rvec_zero(rsum,4);
614       for (PCTFS_ivec_zero(sum,4),ct=i=0;i<n;i++) {
615 
616         if (!used[i]) {
617           /* number of unmarked dofs on node */
618           ct++;
619           /* number of dofs to be marked on lhs hc */
620           if (id< mask) {
621             if (lhs[i]!=0.0) { sum[0]++; rsum[0]+=1.0/lhs[i]; }
622           }
623           /* number of dofs to be marked on rhs hc */
624           if (id>=mask) {
625             if (rhs[i]!=0.0) { sum[1]++; rsum[1]+=1.0/rhs[i]; }
626           }
627         }
628 
629       }
630 
631       /* go for load balance - choose half with most unmarked dofs, bias LHS */
632       (id<mask) ? (sum[2]=ct) : (sum[3]=ct);
633       (id<mask) ? (rsum[2]=ct) : (rsum[3]=ct);
634       PCTFS_giop_hc(sum,w,4,op,edge);
635       PCTFS_grop_hc(rsum,rw,4,op,edge);
636       rsum[0]+=0.1; rsum[1]+=0.1; rsum[2]+=0.1; rsum[3]+=0.1;
637 
638       if (id<mask) {
639         /* mark dofs I own that have signal and not in sep set */
640         for (ct=i=0;i<n;i++) {
641           if ((!used[i])&&(lhs[i]!=0.0)) {
642             ct++; nfo++;
643 
644             if (nfo>n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"nfo about to exceed n\n");
645 
646             *--iptr = local2global[i];
647             used[i]=edge;
648           }
649         }
650         if (ct>1) {PCTFS_ivec_sort(iptr,ct);}
651 
652         lnsep[edge]=ct;
653         nsep[edge]=(PetscInt) rsum[0];
654         dir [edge]=LEFT;
655       }
656 
657       if (id>=mask) {
658         /* mark dofs I own that have signal and not in sep set */
659         for (ct=i=0;i<n;i++) {
660           if ((!used[i])&&(rhs[i]!=0.0)) {
661             ct++; nfo++;
662 
663             if (nfo>n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"nfo about to exceed n\n");
664 
665             *--iptr = local2global[i];
666             used[i]=edge;
667           }
668         }
669         if (ct>1) { PCTFS_ivec_sort(iptr,ct); }
670 
671         lnsep[edge]=ct;
672         nsep[edge]= (PetscInt) rsum[1];
673         dir [edge]=RIGHT;
674       }
675 
676       /* LATER or we can recur on these to order seps at this level */
677       /* do we need full set of separators for this?                */
678 
679       /* fold rhs hc into lower */
680       if (id>=mask) { id-=mask; }
681     }
682   } else {
683     for (iptr=fo+n,id=PCTFS_my_id,mask=PCTFS_num_nodes>>1,edge=level;edge>0;edge--,mask>>=1) {
684       /* set rsh of hc, fire, and collect lhs responses */
685       (id<mask) ? PCTFS_rvec_zero(lhs,m) : PCTFS_rvec_set(lhs,1.0,m);
686       PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",edge);
687 
688       /* set lsh of hc, fire, and collect rhs responses */
689       (id<mask) ? PCTFS_rvec_set(rhs,1.0,m) : PCTFS_rvec_zero(rhs,m);
690       PCTFS_gs_gop_hc(PCTFS_gs_handle,rhs,"+\0",edge);
691 
692       /* count number of dofs I own that have signal and not in sep set */
693       for (PCTFS_ivec_zero(sum,4),ct=i=0;i<n;i++) {
694         if (!used[i]) {
695           /* number of unmarked dofs on node */
696           ct++;
697           /* number of dofs to be marked on lhs hc */
698           if ((id< mask)&&(lhs[i]!=0.0)) { sum[0]++; }
699           /* number of dofs to be marked on rhs hc */
700           if ((id>=mask)&&(rhs[i]!=0.0)) { sum[1]++; }
701         }
702       }
703 
704       /* go for load balance - choose half with most unmarked dofs, bias LHS */
705       (id<mask) ? (sum[2]=ct) : (sum[3]=ct);
706       PCTFS_giop_hc(sum,w,4,op,edge);
707 
708       /* lhs hc wins */
709       if (sum[2]>=sum[3]) {
710         if (id<mask) {
711           /* mark dofs I own that have signal and not in sep set */
712           for (ct=i=0;i<n;i++) {
713             if ((!used[i])&&(lhs[i]!=0.0)) {
714               ct++; nfo++;
715               *--iptr = local2global[i];
716               used[i]=edge;
717             }
718           }
719           if (ct>1) { PCTFS_ivec_sort(iptr,ct); }
720           lnsep[edge]=ct;
721         }
722         nsep[edge]=sum[0];
723         dir [edge]=LEFT;
724       } else { /* rhs hc wins */
725         if (id>=mask) {
726           /* mark dofs I own that have signal and not in sep set */
727           for (ct=i=0;i<n;i++) {
728             if ((!used[i])&&(rhs[i]!=0.0)) {
729               ct++; nfo++;
730               *--iptr = local2global[i];
731               used[i]=edge;
732             }
733           }
734           if (ct>1) {PCTFS_ivec_sort(iptr,ct);}
735           lnsep[edge]=ct;
736         }
737         nsep[edge]=sum[1];
738         dir [edge]=RIGHT;
739       }
740       /* LATER or we can recur on these to order seps at this level */
741       /* do we need full set of separators for this?                */
742 
743       /* fold rhs hc into lower */
744       if (id>=mask) { id-=mask; }
745     }
746   }
747 
748 
749   /* level 0 is on processor case - so mark the remainder */
750   for (ct=i=0;i<n;i++) {
751     if (!used[i]) {
752       ct++; nfo++;
753       *--iptr = local2global[i];
754       used[i]=edge;
755     }
756   }
757   if (ct>1) { PCTFS_ivec_sort(iptr,ct); }
758   lnsep[edge]=ct;
759   nsep [edge]=ct;
760   dir  [edge]=LEFT;
761 
762   xxt_handle->info->nsep=nsep;
763   xxt_handle->info->lnsep=lnsep;
764   xxt_handle->info->fo=fo;
765   xxt_handle->info->nfo=nfo;
766 
767   free(dir);
768   free(lhs);
769   free(rhs);
770   free(used);
771   PetscFunctionReturn(0);
772 }
773 
774 /**************************************xxt.c***********************************/
775 static mv_info *set_mvi(PetscInt *local2global, PetscInt n, PetscInt m, void *matvec, void *grid_data)
776 {
777   mv_info *mvi;
778 
779 
780   mvi = (mv_info*)malloc(sizeof(mv_info));
781   mvi->n=n;
782   mvi->m=m;
783   mvi->n_global=-1;
784   mvi->m_global=-1;
785   mvi->local2global=(PetscInt*)malloc((m+1)*sizeof(PetscInt));
786   PCTFS_ivec_copy(mvi->local2global,local2global,m);
787   mvi->local2global[m] = INT_MAX;
788   mvi->matvec=(PetscErrorCode (*)(mv_info*,PetscScalar*,PetscScalar*))matvec;
789   mvi->grid_data=grid_data;
790 
791   /* set xxt communication handle to perform restricted matvec */
792   mvi->PCTFS_gs_handle = PCTFS_gs_init(local2global, m, PCTFS_num_nodes);
793 
794   return(mvi);
795 }
796 
797 /**************************************xxt.c***********************************/
798 static PetscErrorCode do_matvec(mv_info *A, PetscScalar *v, PetscScalar *u)
799 {
800   PetscFunctionBegin;
801   A->matvec((mv_info*)A->grid_data,v,u);
802   PetscFunctionReturn(0);
803 }
804 
805 
806 
807