xref: /petsc/src/ksp/pc/impls/tfs/xxt.c (revision bebe2cf65d55febe21a5af8db2bd2e168caaa2e7)
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, PetscErrorCode (*matvec)(mv_info*,PetscScalar*,PetscScalar*), 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                     PetscErrorCode (*matvec)(void*,PetscScalar*,PetscScalar*), /* b_loc=A_local.x_loc         */
83                     void *grid_data)        /* grid data for matvec        */
84 {
85   PCTFS_comm_init();
86   check_handle(xxt_handle);
87 
88   /* only 2^k for now and all nodes participating */
89   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);
90 
91   /* space for X info */
92   xxt_handle->info = (xxt_info*)malloc(sizeof(xxt_info));
93 
94   /* set up matvec handles */
95   xxt_handle->mvi = set_mvi(local2global, n, m, (PetscErrorCode (*)(mv_info*,PetscScalar*,PetscScalar*))matvec, grid_data);
96 
97   /* matrix is assumed to be of full rank */
98   /* LATER we can reset to indicate rank def. */
99   xxt_handle->ns=0;
100 
101   /* determine separators and generate firing order - NB xxt info set here */
102   det_separators(xxt_handle);
103 
104   return(do_xxt_factor(xxt_handle));
105 }
106 
107 /**************************************xxt.c***********************************/
108 PetscInt XXT_solve(xxt_ADT xxt_handle, PetscScalar *x, PetscScalar *b)
109 {
110 
111   PCTFS_comm_init();
112   check_handle(xxt_handle);
113 
114   /* need to copy b into x? */
115   if (b) PCTFS_rvec_copy(x,b,xxt_handle->mvi->n);
116   do_xxt_solve(xxt_handle,x);
117 
118   return(0);
119 }
120 
121 /**************************************xxt.c***********************************/
122 PetscInt XXT_free(xxt_ADT xxt_handle)
123 {
124 
125   PCTFS_comm_init();
126   check_handle(xxt_handle);
127   n_xxt_handles--;
128 
129   free(xxt_handle->info->nsep);
130   free(xxt_handle->info->lnsep);
131   free(xxt_handle->info->fo);
132   free(xxt_handle->info->stages);
133   free(xxt_handle->info->solve_uu);
134   free(xxt_handle->info->solve_w);
135   free(xxt_handle->info->x);
136   free(xxt_handle->info->col_vals);
137   free(xxt_handle->info->col_sz);
138   free(xxt_handle->info->col_indices);
139   free(xxt_handle->info);
140   free(xxt_handle->mvi->local2global);
141   PCTFS_gs_free(xxt_handle->mvi->PCTFS_gs_handle);
142   free(xxt_handle->mvi);
143   free(xxt_handle);
144 
145   /* if the check fails we nuke */
146   /* if NULL pointer passed to free we nuke */
147   /* if the calls to free fail that's not my problem */
148   return(0);
149 }
150 
151 /**************************************xxt.c***********************************/
152 PetscInt XXT_stats(xxt_ADT xxt_handle)
153 {
154   PetscInt       op[]  = {NON_UNIFORM,GL_MIN,GL_MAX,GL_ADD,GL_MIN,GL_MAX,GL_ADD,GL_MIN,GL_MAX,GL_ADD};
155   PetscInt       fop[] = {NON_UNIFORM,GL_MIN,GL_MAX,GL_ADD};
156   PetscInt       vals[9],  work[9];
157   PetscScalar    fvals[3], fwork[3];
158   PetscErrorCode ierr;
159 
160   PCTFS_comm_init();
161   check_handle(xxt_handle);
162 
163   /* if factorization not done there are no stats */
164   if (!xxt_handle->info||!xxt_handle->mvi) {
165     if (!PCTFS_my_id) { ierr = PetscPrintf(PETSC_COMM_WORLD,"XXT_stats() :: no stats available!\n");CHKERRQ(ierr); }
166     return 1;
167   }
168 
169   vals[0]=vals[1]=vals[2]=xxt_handle->info->nnz;
170   vals[3]=vals[4]=vals[5]=xxt_handle->mvi->n;
171   vals[6]=vals[7]=vals[8]=xxt_handle->info->msg_buf_sz;
172   PCTFS_giop(vals,work,sizeof(op)/sizeof(op[0])-1,op);
173 
174   fvals[0]=fvals[1]=fvals[2] =xxt_handle->info->tot_solve_time/xxt_handle->info->nsolves++;
175   PCTFS_grop(fvals,fwork,sizeof(fop)/sizeof(fop[0])-1,fop);
176 
177   if (!PCTFS_my_id) {
178     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_nnz=%D\n",PCTFS_my_id,vals[0]);CHKERRQ(ierr);
179     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_nnz=%D\n",PCTFS_my_id,vals[1]);CHKERRQ(ierr);
180     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_nnz=%g\n",PCTFS_my_id,1.0*vals[2]/PCTFS_num_nodes);CHKERRQ(ierr);
181     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: tot   xxt_nnz=%D\n",PCTFS_my_id,vals[2]);CHKERRQ(ierr);
182     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: xxt   C(2d)  =%g\n",PCTFS_my_id,vals[2]/(PetscPowReal(1.0*vals[5],1.5)));CHKERRQ(ierr);
183     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: xxt   C(3d)  =%g\n",PCTFS_my_id,vals[2]/(PetscPowReal(1.0*vals[5],1.6667)));CHKERRQ(ierr);
184     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_n  =%D\n",PCTFS_my_id,vals[3]);CHKERRQ(ierr);
185     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_n  =%D\n",PCTFS_my_id,vals[4]);CHKERRQ(ierr);
186     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_n  =%g\n",PCTFS_my_id,1.0*vals[5]/PCTFS_num_nodes);CHKERRQ(ierr);
187     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: tot   xxt_n  =%D\n",PCTFS_my_id,vals[5]);CHKERRQ(ierr);
188     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_buf=%D\n",PCTFS_my_id,vals[6]);CHKERRQ(ierr);
189     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_buf=%D\n",PCTFS_my_id,vals[7]);CHKERRQ(ierr);
190     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_buf=%g\n",PCTFS_my_id,1.0*vals[8]/PCTFS_num_nodes);CHKERRQ(ierr);
191     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: min   xxt_slv=%g\n",PCTFS_my_id,fvals[0]);CHKERRQ(ierr);
192     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: max   xxt_slv=%g\n",PCTFS_my_id,fvals[1]);CHKERRQ(ierr);
193     ierr = PetscPrintf(PETSC_COMM_WORLD,"%D :: avg   xxt_slv=%g\n",PCTFS_my_id,fvals[2]/PCTFS_num_nodes);CHKERRQ(ierr);
194   }
195 
196   return(0);
197 }
198 
199 /*************************************xxt.c************************************
200 
201 Description: get A_local, local portion of global coarse matrix which
202 is a row dist. nxm matrix w/ n<m.
203    o my_ml holds address of ML struct associated w/A_local and coarse grid
204    o local2global holds global number of column i (i=0,...,m-1)
205    o local2global holds global number of row    i (i=0,...,n-1)
206    o mylocmatvec performs A_local . vec_local (note that gs is performed using
207    PCTFS_gs_init/gop).
208 
209 mylocmatvec = my_ml->Amat[grid_tag].matvec->external;
210 mylocmatvec (void :: void *data, double *in, double *out)
211 **************************************xxt.c***********************************/
212 static PetscInt do_xxt_factor(xxt_ADT xxt_handle)
213 {
214   return xxt_generate(xxt_handle);
215 }
216 
217 /**************************************xxt.c***********************************/
218 static PetscInt xxt_generate(xxt_ADT xxt_handle)
219 {
220   PetscInt       i,j,k,idex;
221   PetscInt       dim, col;
222   PetscScalar    *u, *uu, *v, *z, *w, alpha, alpha_w;
223   PetscInt       *segs;
224   PetscInt       op[] = {GL_ADD,0};
225   PetscInt       off, len;
226   PetscScalar    *x_ptr;
227   PetscInt       *iptr, flag;
228   PetscInt       start =0, end, work;
229   PetscInt       op2[] = {GL_MIN,0};
230   PCTFS_gs_ADT   PCTFS_gs_handle;
231   PetscInt       *nsep, *lnsep, *fo;
232   PetscInt       a_n            =xxt_handle->mvi->n;
233   PetscInt       a_m            =xxt_handle->mvi->m;
234   PetscInt       *a_local2global=xxt_handle->mvi->local2global;
235   PetscInt       level;
236   PetscInt       xxt_nnz=0, xxt_max_nnz=0;
237   PetscInt       n, m;
238   PetscInt       *col_sz, *col_indices, *stages;
239   PetscScalar    **col_vals, *x;
240   PetscInt       n_global;
241   PetscInt       xxt_zero_nnz  =0;
242   PetscInt       xxt_zero_nnz_0=0;
243   PetscBLASInt   i1            = 1,dlen;
244   PetscScalar    dm1           = -1.0;
245   PetscErrorCode ierr;
246 
247   n               = xxt_handle->mvi->n;
248   nsep            = xxt_handle->info->nsep;
249   lnsep           = xxt_handle->info->lnsep;
250   fo              = xxt_handle->info->fo;
251   end             = lnsep[0];
252   level           = xxt_handle->level;
253   PCTFS_gs_handle = xxt_handle->mvi->PCTFS_gs_handle;
254 
255   /* is there a null space? */
256   /* LATER add in ability to detect null space by checking alpha */
257   for (i=0, j=0; i<=level; i++) j+=nsep[i];
258 
259   m = j-xxt_handle->ns;
260   if (m!=j) {
261     ierr = PetscPrintf(PETSC_COMM_WORLD,"xxt_generate() :: null space exists %D %D %D\n",m,j,xxt_handle->ns);CHKERRQ(ierr);
262   }
263 
264   /* get and initialize storage for x local         */
265   /* note that x local is nxm and stored by columns */
266   col_sz      = (PetscInt*) malloc(m*sizeof(PetscInt));
267   col_indices = (PetscInt*) malloc((2*m+1)*sizeof(PetscInt));
268   col_vals    = (PetscScalar**) malloc(m*sizeof(PetscScalar*));
269   for (i=j=0; i<m; i++, j+=2) {
270     col_indices[j]=col_indices[j+1]=col_sz[i]=-1;
271     col_vals[i]   = NULL;
272   }
273   col_indices[j]=-1;
274 
275   /* size of separators for each sub-hc working from bottom of tree to top */
276   /* this looks like nsep[]=segments */
277   stages = (PetscInt*) malloc((level+1)*sizeof(PetscInt));
278   segs   = (PetscInt*) malloc((level+1)*sizeof(PetscInt));
279   PCTFS_ivec_zero(stages,level+1);
280   PCTFS_ivec_copy(segs,nsep,level+1);
281   for (i=0; i<level; i++) segs[i+1] += segs[i];
282   stages[0] = segs[0];
283 
284   /* temporary vectors  */
285   u  = (PetscScalar*) malloc(n*sizeof(PetscScalar));
286   z  = (PetscScalar*) malloc(n*sizeof(PetscScalar));
287   v  = (PetscScalar*) malloc(a_m*sizeof(PetscScalar));
288   uu = (PetscScalar*) malloc(m*sizeof(PetscScalar));
289   w  = (PetscScalar*) malloc(m*sizeof(PetscScalar));
290 
291   /* extra nnz due to replication of vertices across separators */
292   for (i=1, j=0; i<=level; i++) j+=nsep[i];
293 
294   /* storage for sparse x values */
295   n_global    = xxt_handle->info->n_global;
296   xxt_max_nnz = (PetscInt)(2.5*PetscPowReal(1.0*n_global,1.6667) + j*n/2)/PCTFS_num_nodes;
297   x           = (PetscScalar*) malloc(xxt_max_nnz*sizeof(PetscScalar));
298   xxt_nnz     = 0;
299 
300   /* LATER - can embed next sep to fire in gs */
301   /* time to make the donuts - generate X factor */
302   for (dim=i=j=0; i<m; i++) {
303     /* time to move to the next level? */
304     while (i==segs[dim]) {
305       if (dim==level) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"dim about to exceed level\n");
306       stages[dim++]=i;
307       end         +=lnsep[dim];
308     }
309     stages[dim]=i;
310 
311     /* which column are we firing? */
312     /* i.e. set v_l */
313     /* use new seps and do global min across hc to determine which one to fire */
314     (start<end) ? (col=fo[start]) : (col=INT_MAX);
315     PCTFS_giop_hc(&col,&work,1,op2,dim);
316 
317     /* shouldn't need this */
318     if (col==INT_MAX) {
319       ierr = PetscInfo(0,"hey ... col==INT_MAX??\n");CHKERRQ(ierr);
320       continue;
321     }
322 
323     /* do I own it? I should */
324     PCTFS_rvec_zero(v,a_m);
325     if (col==fo[start]) {
326       start++;
327       idex=PCTFS_ivec_linear_search(col, a_local2global, a_n);
328       if (idex!=-1) {
329         v[idex] = 1.0; j++;
330       } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"NOT FOUND!\n");
331     } else {
332       idex=PCTFS_ivec_linear_search(col, a_local2global, a_m);
333       if (idex!=-1) v[idex] = 1.0;
334     }
335 
336     /* perform u = A.v_l */
337     PCTFS_rvec_zero(u,n);
338     do_matvec(xxt_handle->mvi,v,u);
339 
340     /* uu =  X^T.u_l (local portion) */
341     /* technically only need to zero out first i entries */
342     /* later turn this into an XXT_solve call ? */
343     PCTFS_rvec_zero(uu,m);
344     x_ptr=x;
345     iptr = col_indices;
346     for (k=0; k<i; k++) {
347       off   = *iptr++;
348       len   = *iptr++;
349       ierr  = PetscBLASIntCast(len,&dlen);CHKERRQ(ierr);
350       PetscStackCallBLAS("BLASdot",uu[k] = BLASdot_(&dlen,u+off,&i1,x_ptr,&i1));
351       x_ptr+=len;
352     }
353 
354 
355     /* uu = X^T.u_l (comm portion) */
356     PCTFS_ssgl_radd  (uu, w, dim, stages);
357 
358     /* z = X.uu */
359     PCTFS_rvec_zero(z,n);
360     x_ptr=x;
361     iptr = col_indices;
362     for (k=0; k<i; k++) {
363       off  = *iptr++;
364       len  = *iptr++;
365       ierr = PetscBLASIntCast(len,&dlen);CHKERRQ(ierr);
366       PetscStackCallBLAS("BLASaxpy",BLASaxpy_(&dlen,&uu[k],x_ptr,&i1,z+off,&i1));
367       x_ptr+=len;
368     }
369 
370     /* compute v_l = v_l - z */
371     PCTFS_rvec_zero(v+a_n,a_m-a_n);
372     ierr = PetscBLASIntCast(n,&dlen);CHKERRQ(ierr);
373     PetscStackCallBLAS("BLASaxpy",BLASaxpy_(&dlen,&dm1,z,&i1,v,&i1));
374 
375     /* compute u_l = A.v_l */
376     if (a_n!=a_m) PCTFS_gs_gop_hc(PCTFS_gs_handle,v,"+\0",dim);
377     PCTFS_rvec_zero(u,n);
378     do_matvec(xxt_handle->mvi,v,u);
379 
380     /* compute sqrt(alpha) = sqrt(v_l^T.u_l) - local portion */
381     ierr  = PetscBLASIntCast(n,&dlen);CHKERRQ(ierr);
382     PetscStackCallBLAS("BLASdot",alpha = BLASdot_(&dlen,u,&i1,v,&i1));
383     /* compute sqrt(alpha) = sqrt(v_l^T.u_l) - comm portion */
384     PCTFS_grop_hc(&alpha, &alpha_w, 1, op, dim);
385 
386     alpha = (PetscScalar) PetscSqrtReal((PetscReal)alpha);
387 
388     /* check for small alpha                             */
389     /* LATER use this to detect and determine null space */
390     if (PetscAbsScalar(alpha)<1.0e-14) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"bad alpha! %g\n",alpha);
391 
392     /* compute v_l = v_l/sqrt(alpha) */
393     PCTFS_rvec_scale(v,1.0/alpha,n);
394 
395     /* add newly generated column, v_l, to X */
396     flag = 1;
397     off=len=0;
398     for (k=0; k<n; k++) {
399       if (v[k]!=0.0) {
400         len=k;
401         if (flag) { off=k; flag=0; }
402       }
403     }
404 
405     len -= (off-1);
406 
407     if (len>0) {
408       if ((xxt_nnz+len)>xxt_max_nnz) {
409         ierr         = PetscInfo(0,"increasing space for X by 2x!\n");CHKERRQ(ierr);
410         xxt_max_nnz *= 2;
411         x_ptr        = (PetscScalar*) malloc(xxt_max_nnz*sizeof(PetscScalar));
412         PCTFS_rvec_copy(x_ptr,x,xxt_nnz);
413         free(x);
414         x     = x_ptr;
415         x_ptr+=xxt_nnz;
416       }
417       xxt_nnz += len;
418       PCTFS_rvec_copy(x_ptr,v+off,len);
419 
420       /* keep track of number of zeros */
421       if (dim) {
422         for (k=0; k<len; k++) {
423           if (x_ptr[k]==0.0) xxt_zero_nnz++;
424         }
425       } else {
426         for (k=0; k<len; k++) {
427           if (x_ptr[k]==0.0) xxt_zero_nnz_0++;
428         }
429       }
430       col_indices[2*i] = off;
431       col_sz[i] = col_indices[2*i+1] = len;
432       col_vals[i] = x_ptr;
433     }
434     else {
435       col_indices[2*i] = 0;
436       col_sz[i]        = col_indices[2*i+1] = 0;
437       col_vals[i]      = x_ptr;
438     }
439   }
440 
441   /* close off stages for execution phase */
442   while (dim!=level) {
443     stages[dim++] = i;
444     ierr          = PetscInfo2(0,"disconnected!!! dim(%D)!=level(%D)\n",dim,level);CHKERRQ(ierr);
445   }
446   stages[dim]=i;
447 
448   xxt_handle->info->n              = xxt_handle->mvi->n;
449   xxt_handle->info->m              = m;
450   xxt_handle->info->nnz            = xxt_nnz;
451   xxt_handle->info->max_nnz        = xxt_max_nnz;
452   xxt_handle->info->msg_buf_sz     = stages[level]-stages[0];
453   xxt_handle->info->solve_uu       = (PetscScalar*) malloc(m*sizeof(PetscScalar));
454   xxt_handle->info->solve_w        = (PetscScalar*) malloc(m*sizeof(PetscScalar));
455   xxt_handle->info->x              = x;
456   xxt_handle->info->col_vals       = col_vals;
457   xxt_handle->info->col_sz         = col_sz;
458   xxt_handle->info->col_indices    = col_indices;
459   xxt_handle->info->stages         = stages;
460   xxt_handle->info->nsolves        = 0;
461   xxt_handle->info->tot_solve_time = 0.0;
462 
463   free(segs);
464   free(u);
465   free(v);
466   free(uu);
467   free(z);
468   free(w);
469 
470   return(0);
471 }
472 
473 /**************************************xxt.c***********************************/
474 static PetscErrorCode do_xxt_solve(xxt_ADT xxt_handle,  PetscScalar *uc)
475 {
476   PetscInt       off, len, *iptr;
477   PetscInt       level        = xxt_handle->level;
478   PetscInt       n            = xxt_handle->info->n;
479   PetscInt       m            = xxt_handle->info->m;
480   PetscInt       *stages      = xxt_handle->info->stages;
481   PetscInt       *col_indices = xxt_handle->info->col_indices;
482   PetscScalar    *x_ptr, *uu_ptr;
483   PetscScalar    *solve_uu = xxt_handle->info->solve_uu;
484   PetscScalar    *solve_w  = xxt_handle->info->solve_w;
485   PetscScalar    *x        = xxt_handle->info->x;
486   PetscBLASInt   i1        = 1,dlen;
487   PetscErrorCode ierr;
488 
489   PetscFunctionBegin;
490   uu_ptr=solve_uu;
491   PCTFS_rvec_zero(uu_ptr,m);
492 
493   /* x  = X.Y^T.b */
494   /* uu = Y^T.b */
495   for (x_ptr=x,iptr=col_indices; *iptr!=-1; x_ptr+=len) {
496     off       =*iptr++;
497     len       =*iptr++;
498     ierr      = PetscBLASIntCast(len,&dlen);CHKERRQ(ierr);
499     PetscStackCallBLAS("BLASdot",*uu_ptr++ = BLASdot_(&dlen,uc+off,&i1,x_ptr,&i1));
500   }
501 
502   /* comunication of beta */
503   uu_ptr=solve_uu;
504   if (level) PCTFS_ssgl_radd(uu_ptr, solve_w, level, stages);
505 
506   PCTFS_rvec_zero(uc,n);
507 
508   /* x = X.uu */
509   for (x_ptr=x,iptr=col_indices; *iptr!=-1; x_ptr+=len) {
510     off  =*iptr++;
511     len  =*iptr++;
512     ierr = PetscBLASIntCast(len,&dlen);CHKERRQ(ierr);
513     PetscStackCallBLAS("BLASaxpy",BLASaxpy_(&dlen,uu_ptr++,x_ptr,&i1,uc+off,&i1));
514   }
515   PetscFunctionReturn(0);
516 }
517 
518 /**************************************xxt.c***********************************/
519 static PetscErrorCode check_handle(xxt_ADT xxt_handle)
520 {
521   PetscInt vals[2], work[2], op[] = {NON_UNIFORM,GL_MIN,GL_MAX};
522 
523   PetscFunctionBegin;
524   if (!xxt_handle) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_PLIB,"check_handle() :: bad handle :: NULL %D\n",xxt_handle);
525 
526   vals[0]=vals[1]=xxt_handle->id;
527   PCTFS_giop(vals,work,sizeof(op)/sizeof(op[0])-1,op);
528   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);
529   PetscFunctionReturn(0);
530 }
531 
532 /**************************************xxt.c***********************************/
533 static PetscErrorCode det_separators(xxt_ADT xxt_handle)
534 {
535   PetscInt     i, ct, id;
536   PetscInt     mask, edge, *iptr;
537   PetscInt     *dir, *used;
538   PetscInt     sum[4], w[4];
539   PetscScalar  rsum[4], rw[4];
540   PetscInt     op[] = {GL_ADD,0};
541   PetscScalar  *lhs, *rhs;
542   PetscInt     *nsep, *lnsep, *fo, nfo=0;
543   PCTFS_gs_ADT PCTFS_gs_handle = xxt_handle->mvi->PCTFS_gs_handle;
544   PetscInt     *local2global   = xxt_handle->mvi->local2global;
545   PetscInt     n               = xxt_handle->mvi->n;
546   PetscInt     m               = xxt_handle->mvi->m;
547   PetscInt     level           = xxt_handle->level;
548   PetscInt     shared          = 0;
549 
550   PetscFunctionBegin;
551   dir  = (PetscInt*)malloc(sizeof(PetscInt)*(level+1));
552   nsep = (PetscInt*)malloc(sizeof(PetscInt)*(level+1));
553   lnsep= (PetscInt*)malloc(sizeof(PetscInt)*(level+1));
554   fo   = (PetscInt*)malloc(sizeof(PetscInt)*(n+1));
555   used = (PetscInt*)malloc(sizeof(PetscInt)*n);
556 
557   PCTFS_ivec_zero(dir,level+1);
558   PCTFS_ivec_zero(nsep,level+1);
559   PCTFS_ivec_zero(lnsep,level+1);
560   PCTFS_ivec_set (fo,-1,n+1);
561   PCTFS_ivec_zero(used,n);
562 
563   lhs = (PetscScalar*)malloc(sizeof(PetscScalar)*m);
564   rhs = (PetscScalar*)malloc(sizeof(PetscScalar)*m);
565 
566   /* determine the # of unique dof */
567   PCTFS_rvec_zero(lhs,m);
568   PCTFS_rvec_set(lhs,1.0,n);
569   PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",level);
570   PCTFS_rvec_zero(rsum,2);
571   for (ct=i=0; i<n; i++) {
572     if (lhs[i]!=0.0) {
573       rsum[0]+=1.0/lhs[i]; rsum[1]+=lhs[i];
574     }
575   }
576   PCTFS_grop_hc(rsum,rw,2,op,level);
577   rsum[0]+=0.1;
578   rsum[1]+=0.1;
579 
580   if (PetscAbsScalar(rsum[0]-rsum[1])>EPS) shared=1;
581 
582   xxt_handle->info->n_global=xxt_handle->info->m_global=(PetscInt) rsum[0];
583   xxt_handle->mvi->n_global =xxt_handle->mvi->m_global =(PetscInt) rsum[0];
584 
585   /* determine separator sets top down */
586   if (shared) {
587     for (iptr=fo+n,id=PCTFS_my_id,mask=PCTFS_num_nodes>>1,edge=level;edge>0;edge--,mask>>=1) {
588 
589       /* set rsh of hc, fire, and collect lhs responses */
590       (id<mask) ? PCTFS_rvec_zero(lhs,m) : PCTFS_rvec_set(lhs,1.0,m);
591       PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",edge);
592 
593       /* set lsh of hc, fire, and collect rhs responses */
594       (id<mask) ? PCTFS_rvec_set(rhs,1.0,m) : PCTFS_rvec_zero(rhs,m);
595       PCTFS_gs_gop_hc(PCTFS_gs_handle,rhs,"+\0",edge);
596 
597       for (i=0;i<n;i++) {
598         if (id< mask) {
599           if (lhs[i]!=0.0) lhs[i]=1.0;
600         }
601 
602         if (id>=mask) {
603           if (rhs[i]!=0.0) rhs[i]=1.0;
604         }
605       }
606 
607       if (id< mask) PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",edge-1);
608       else          PCTFS_gs_gop_hc(PCTFS_gs_handle,rhs,"+\0",edge-1);
609 
610       /* count number of dofs I own that have signal and not in sep set */
611       PCTFS_rvec_zero(rsum,4);
612       for (PCTFS_ivec_zero(sum,4),ct=i=0;i<n;i++) {
613 
614         if (!used[i]) {
615           /* number of unmarked dofs on node */
616           ct++;
617           /* number of dofs to be marked on lhs hc */
618           if (id< mask) {
619             if (lhs[i]!=0.0) { sum[0]++; rsum[0]+=1.0/lhs[i]; }
620           }
621           /* number of dofs to be marked on rhs hc */
622           if (id>=mask) {
623             if (rhs[i]!=0.0) { sum[1]++; rsum[1]+=1.0/rhs[i]; }
624           }
625         }
626       }
627 
628       /* go for load balance - choose half with most unmarked dofs, bias LHS */
629       (id<mask) ? (sum[2]=ct) : (sum[3]=ct);
630       (id<mask) ? (rsum[2]=ct) : (rsum[3]=ct);
631       PCTFS_giop_hc(sum,w,4,op,edge);
632       PCTFS_grop_hc(rsum,rw,4,op,edge);
633       rsum[0]+=0.1; rsum[1]+=0.1; rsum[2]+=0.1; rsum[3]+=0.1;
634 
635       if (id<mask) {
636         /* mark dofs I own that have signal and not in sep set */
637         for (ct=i=0;i<n;i++) {
638           if ((!used[i])&&(lhs[i]!=0.0)) {
639             ct++; nfo++;
640 
641             if (nfo>n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"nfo about to exceed n\n");
642 
643             *--iptr = local2global[i];
644             used[i] = edge;
645           }
646         }
647         if (ct>1) PCTFS_ivec_sort(iptr,ct);
648 
649         lnsep[edge]=ct;
650         nsep[edge]=(PetscInt) rsum[0];
651         dir [edge]=LEFT;
652       }
653 
654       if (id>=mask) {
655         /* mark dofs I own that have signal and not in sep set */
656         for (ct=i=0;i<n;i++) {
657           if ((!used[i])&&(rhs[i]!=0.0)) {
658             ct++; nfo++;
659 
660             if (nfo>n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"nfo about to exceed n\n");
661 
662             *--iptr = local2global[i];
663             used[i] = edge;
664           }
665         }
666         if (ct>1) PCTFS_ivec_sort(iptr,ct);
667 
668         lnsep[edge] = ct;
669         nsep[edge]  = (PetscInt) rsum[1];
670         dir [edge]  = RIGHT;
671       }
672 
673       /* LATER or we can recur on these to order seps at this level */
674       /* do we need full set of separators for this?                */
675 
676       /* fold rhs hc into lower */
677       if (id>=mask) id-=mask;
678     }
679   } else {
680     for (iptr=fo+n,id=PCTFS_my_id,mask=PCTFS_num_nodes>>1,edge=level;edge>0;edge--,mask>>=1) {
681       /* set rsh of hc, fire, and collect lhs responses */
682       (id<mask) ? PCTFS_rvec_zero(lhs,m) : PCTFS_rvec_set(lhs,1.0,m);
683       PCTFS_gs_gop_hc(PCTFS_gs_handle,lhs,"+\0",edge);
684 
685       /* set lsh of hc, fire, and collect rhs responses */
686       (id<mask) ? PCTFS_rvec_set(rhs,1.0,m) : PCTFS_rvec_zero(rhs,m);
687       PCTFS_gs_gop_hc(PCTFS_gs_handle,rhs,"+\0",edge);
688 
689       /* count number of dofs I own that have signal and not in sep set */
690       for (PCTFS_ivec_zero(sum,4),ct=i=0;i<n;i++) {
691         if (!used[i]) {
692           /* number of unmarked dofs on node */
693           ct++;
694           /* number of dofs to be marked on lhs hc */
695           if ((id< mask)&&(lhs[i]!=0.0)) sum[0]++;
696           /* number of dofs to be marked on rhs hc */
697           if ((id>=mask)&&(rhs[i]!=0.0)) sum[1]++;
698         }
699       }
700 
701       /* go for load balance - choose half with most unmarked dofs, bias LHS */
702       (id<mask) ? (sum[2]=ct) : (sum[3]=ct);
703       PCTFS_giop_hc(sum,w,4,op,edge);
704 
705       /* lhs hc wins */
706       if (sum[2]>=sum[3]) {
707         if (id<mask) {
708           /* mark dofs I own that have signal and not in sep set */
709           for (ct=i=0;i<n;i++) {
710             if ((!used[i])&&(lhs[i]!=0.0)) {
711               ct++; nfo++;
712               *--iptr = local2global[i];
713               used[i]=edge;
714             }
715           }
716           if (ct>1) PCTFS_ivec_sort(iptr,ct);
717           lnsep[edge]=ct;
718         }
719         nsep[edge]=sum[0];
720         dir [edge]=LEFT;
721       } else { /* rhs hc wins */
722         if (id>=mask) {
723           /* mark dofs I own that have signal and not in sep set */
724           for (ct=i=0;i<n;i++) {
725             if ((!used[i])&&(rhs[i]!=0.0)) {
726               ct++; nfo++;
727               *--iptr = local2global[i];
728               used[i]=edge;
729             }
730           }
731           if (ct>1) PCTFS_ivec_sort(iptr,ct);
732           lnsep[edge]=ct;
733         }
734         nsep[edge]=sum[1];
735         dir [edge]=RIGHT;
736       }
737       /* LATER or we can recur on these to order seps at this level */
738       /* do we need full set of separators for this?                */
739 
740       /* fold rhs hc into lower */
741       if (id>=mask) id-=mask;
742     }
743   }
744 
745 
746   /* level 0 is on processor case - so mark the remainder */
747   for (ct=i=0; i<n; i++) {
748     if (!used[i]) {
749       ct++; nfo++;
750       *--iptr = local2global[i];
751       used[i] = edge;
752     }
753   }
754   if (ct>1) PCTFS_ivec_sort(iptr,ct);
755   lnsep[edge]=ct;
756   nsep [edge]=ct;
757   dir  [edge]=LEFT;
758 
759   xxt_handle->info->nsep  = nsep;
760   xxt_handle->info->lnsep = lnsep;
761   xxt_handle->info->fo    = fo;
762   xxt_handle->info->nfo   = nfo;
763 
764   free(dir);
765   free(lhs);
766   free(rhs);
767   free(used);
768   PetscFunctionReturn(0);
769 }
770 
771 /**************************************xxt.c***********************************/
772 static mv_info *set_mvi(PetscInt *local2global,PetscInt n,PetscInt m,PetscErrorCode (*matvec)(mv_info*,PetscScalar*,PetscScalar*),void *grid_data)
773 {
774   mv_info *mvi;
775 
776 
777   mvi               = (mv_info*)malloc(sizeof(mv_info));
778   mvi->n            = n;
779   mvi->m            = m;
780   mvi->n_global     = -1;
781   mvi->m_global     = -1;
782   mvi->local2global = (PetscInt*)malloc((m+1)*sizeof(PetscInt));
783   PCTFS_ivec_copy(mvi->local2global,local2global,m);
784   mvi->local2global[m] = INT_MAX;
785   mvi->matvec          = matvec;
786   mvi->grid_data       = grid_data;
787 
788   /* set xxt communication handle to perform restricted matvec */
789   mvi->PCTFS_gs_handle = PCTFS_gs_init(local2global, m, PCTFS_num_nodes);
790 
791   return(mvi);
792 }
793 
794 /**************************************xxt.c***********************************/
795 static PetscErrorCode do_matvec(mv_info *A, PetscScalar *v, PetscScalar *u)
796 {
797   PetscFunctionBegin;
798   A->matvec((mv_info*)A->grid_data,v,u);
799   PetscFunctionReturn(0);
800 }
801 
802 
803 
804