/[escript]/trunk/paso/src/Solver_AMG.c
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Annotation of /trunk/paso/src/Solver_AMG.c

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Revision 2784 - (hide annotations)
Thu Nov 26 05:09:14 2009 UTC (10 years, 2 months ago) by artak
File MIME type: text/plain
File size: 19948 byte(s)
More performance tunning. Sparsity check is added. If Coarse level matrix is denser than 1% then stop.
1 jfenwick 1851
2     /*******************************************************
3     *
4 jfenwick 2548 * Copyright (c) 2003-2009 by University of Queensland
5 jfenwick 1851 * Earth Systems Science Computational Center (ESSCC)
6     * http://www.uq.edu.au/esscc
7     *
8     * Primary Business: Queensland, Australia
9     * Licensed under the Open Software License version 3.0
10     * http://www.opensource.org/licenses/osl-3.0.php
11     *
12     *******************************************************/
13    
14    
15     /**************************************************************/
16    
17 artak 2475 /* Paso: AMG preconditioner */
18 jfenwick 1851
19     /**************************************************************/
20    
21 jfenwick 2625 /* Author: artak@uq.edu.au */
22 jfenwick 1851
23     /**************************************************************/
24    
25     #include "Paso.h"
26     #include "Solver.h"
27 artak 2475 #include "Options.h"
28 jfenwick 1851 #include "PasoUtil.h"
29 artak 1931 #include "UMFPACK.h"
30 artak 2507 #include "MKL.h"
31     #include "SystemMatrix.h"
32 phornby 1917 #include "Pattern_coupling.h"
33 jfenwick 1851
34     /**************************************************************/
35    
36     /* free all memory used by AMG */
37    
38 artak 2659 void Paso_Solver_AMG_System_free(Paso_Solver_AMG_System * in) {
39 artak 2662 dim_t i;
40 artak 2659 if (in!=NULL) {
41 artak 2662 for (i=0;i<in->block_size;++i) {
42     Paso_Solver_AMG_free(in->amgblock[i]);
43 artak 2670 Paso_SparseMatrix_free(in->block[i]);
44 artak 2662 }
45 artak 2659 MEMFREE(in);
46     }
47     }
48    
49    
50     /* free all memory used by AMG */
51    
52 jfenwick 1851 void Paso_Solver_AMG_free(Paso_Solver_AMG * in) {
53     if (in!=NULL) {
54 artak 2112 Paso_Solver_Jacobi_free(in->GS);
55 jfenwick 1851 Paso_SparseMatrix_free(in->A_FC);
56 artak 2760 Paso_SparseMatrix_free(in->A_FF);
57     Paso_SparseMatrix_free(in->W_FC);
58 jfenwick 1851 Paso_SparseMatrix_free(in->A_CF);
59 artak 2760 Paso_SparseMatrix_free(in->P);
60     Paso_SparseMatrix_free(in->R);
61 artak 2556 Paso_SparseMatrix_free(in->A);
62 artak 2711 if(in->coarsest_level==TRUE) {
63     #ifdef MKL
64     Paso_MKL_free1(in->AOffset1);
65     Paso_SparseMatrix_free(in->AOffset1);
66     #else
67     #ifdef UMFPACK
68     Paso_UMFPACK1_free((Paso_UMFPACK_Handler*)(in->solver));
69     #endif
70     #endif
71     }
72 jfenwick 1851 MEMFREE(in->rows_in_F);
73     MEMFREE(in->rows_in_C);
74     MEMFREE(in->mask_F);
75     MEMFREE(in->mask_C);
76     MEMFREE(in->x_F);
77     MEMFREE(in->b_F);
78     MEMFREE(in->x_C);
79     MEMFREE(in->b_C);
80 gross 2551 in->solver=NULL;
81 artak 2760 Paso_Solver_AMG_free(in->AMG_of_Coarse);
82 gross 2551 MEMFREE(in->b_C);
83 jfenwick 1851 MEMFREE(in);
84     }
85     }
86    
87     /**************************************************************/
88    
89     /* constructs the block-block factorization of
90    
91     [ A_FF A_FC ]
92     A_p=
93     [ A_CF A_FF ]
94    
95     to
96    
97     [ I 0 ] [ A_FF 0 ] [ I invA_FF*A_FF ]
98     [ A_CF*invA_FF I ] [ 0 S ] [ 0 I ]
99    
100    
101     where S=A_FF-ACF*invA_FF*A_FC within the shape of S
102    
103     then AMG is applied to S again until S becomes empty
104    
105     */
106 artak 2520 Paso_Solver_AMG* Paso_Solver_getAMG(Paso_SparseMatrix *A_p,dim_t level,Paso_Options* options) {
107 jfenwick 1851 Paso_Solver_AMG* out=NULL;
108 artak 2760 /*
109     Paso_Pattern* temp1=NULL;
110 artak 2556 Paso_Pattern* temp2=NULL;
111 artak 2760 */
112 artak 2520 bool_t verbose=options->verbose;
113 jfenwick 1851 dim_t n=A_p->numRows;
114     dim_t n_block=A_p->row_block_size;
115     index_t* mis_marker=NULL;
116 artak 1881 index_t* counter=NULL;
117 artak 2760 /*index_t iPtr,*index, *where_p;*/
118     dim_t i;
119     Paso_SparseMatrix * A_c=NULL;
120 artak 2765 double time0=0;
121 artak 2784 Paso_SparseMatrix * Atemp=NULL;
122     double sparsity=0;
123 artak 2475
124 artak 2760 /*
125     double *temp,*temp_1;
126     double S;
127     index_t iptr;
128     */
129 artak 2784 verbose=1;
130 artak 2760 /*char filename[8];*/
131     /*sprintf(filename,"AMGLevel%d",level);
132 artak 2726
133 artak 2760 Paso_SparseMatrix_saveMM(A_p,filename);
134 artak 2726 */
135    
136 artak 2439 /*Make sure we have block sizes 1*/
137 gross 2550 if (A_p->col_block_size>1) {
138     Paso_setError(TYPE_ERROR,"Paso_Solver_getAMG: AMG requires column block size 1.");
139     return NULL;
140     }
141     if (A_p->row_block_size>1) {
142     Paso_setError(TYPE_ERROR,"Paso_Solver_getAMG: AMG requires row block size 1.");
143     return NULL;
144     }
145 gross 2551 out=MEMALLOC(1,Paso_Solver_AMG);
146 jfenwick 1851 /* identify independend set of rows/columns */
147     mis_marker=TMPMEMALLOC(n,index_t);
148     counter=TMPMEMALLOC(n,index_t);
149 gross 2551 if ( !( Paso_checkPtr(mis_marker) || Paso_checkPtr(counter) || Paso_checkPtr(out)) ) {
150 artak 2760 out->AMG_of_Coarse=NULL;
151     out->A_FF=NULL;
152 gross 2551 out->A_FC=NULL;
153     out->A_CF=NULL;
154 artak 2760 out->W_FC=NULL;
155     out->P=NULL;
156     out->R=NULL;
157 gross 2551 out->rows_in_F=NULL;
158     out->rows_in_C=NULL;
159     out->mask_F=NULL;
160     out->mask_C=NULL;
161     out->x_F=NULL;
162     out->b_F=NULL;
163     out->x_C=NULL;
164     out->b_C=NULL;
165     out->GS=NULL;
166     out->A=Paso_SparseMatrix_getReference(A_p);
167     out->GS=NULL;
168     out->solver=NULL;
169     /*out->GS=Paso_Solver_getGS(A_p,verbose);*/
170     out->level=level;
171 artak 2661 out->n=n;
172 artak 2726 out->n_F=n+1;
173 artak 2661 out->n_block=n_block;
174 artak 2556
175 artak 2784 sparsity=(A_p->len*1.)/(1.*A_p->numRows*A_p->numCols);
176    
177     if (verbose) fprintf(stdout,"Stats: Sparsity of the Coarse Matrix with %d non-zeros (%d,%d) in level %d is %.6f\n",A_p->len,A_p->numRows,A_p->numCols,level,sparsity);
178    
179     if(sparsity>0.01) {
180     level=0;
181     }
182    
183    
184 gross 2551 if (level==0 || n<=options->min_coarse_matrix_size) {
185     out->coarsest_level=TRUE;
186 artak 2784 /*out->GS=Paso_Solver_getJacobi(A_p);*/
187    
188 artak 2712 #ifdef MKL
189 artak 2711 out->AOffset1=Paso_SparseMatrix_alloc(MATRIX_FORMAT_BLK1 + MATRIX_FORMAT_OFFSET1, out->A->pattern,1,1, FALSE);
190     #pragma omp parallel for private(i) schedule(static)
191     for (i=0;i<out->A->len;++i) {
192     out->AOffset1->val[i]=out->A->val[i];
193     }
194 artak 2712 #else
195     #ifdef UMFPACK
196     #else
197 gross 2551 out->GS=Paso_Solver_getJacobi(A_p);
198     #endif
199     #endif
200 artak 2784
201 gross 2551 } else {
202     out->coarsest_level=FALSE;
203     out->GS=Paso_Solver_getJacobi(A_p);
204 artak 2442
205 gross 2551 /* identify independend set of rows/columns */
206     #pragma omp parallel for private(i) schedule(static)
207     for (i=0;i<n;++i) mis_marker[i]=-1;
208    
209 artak 2765 /*mesuring coarsening time */
210     time0=Paso_timer();
211    
212 gross 2551 if (options->coarsening_method == PASO_YAIR_SHAPIRA_COARSENING) {
213 artak 2652 Paso_Pattern_YS(A_p,mis_marker,options->coarsening_threshold);
214 gross 2551 }
215     else if (options->coarsening_method == PASO_RUGE_STUEBEN_COARSENING) {
216     Paso_Pattern_RS(A_p,mis_marker,options->coarsening_threshold);
217     }
218     else if (options->coarsening_method == PASO_AGGREGATION_COARSENING) {
219     Paso_Pattern_Aggregiation(A_p,mis_marker,options->coarsening_threshold);
220     }
221     else {
222     /*Default coarseneing*/
223 artak 2760 Paso_Pattern_RS_MI(A_p,mis_marker,options->coarsening_threshold);
224 artak 2659 /*Paso_Pattern_YS(A_p,mis_marker,options->coarsening_threshold);*/
225 artak 2760 /*Paso_Pattern_RS(A_p,mis_marker,options->coarsening_threshold);*/
226 artak 2726 /*Paso_Pattern_Aggregiation(A_p,mis_marker,options->coarsening_threshold);*/
227 artak 2760
228 gross 2551 }
229 artak 2765
230 artak 2784 if (verbose) fprintf(stdout,"timing: Profilining for level %d:\n",level);
231 artak 2767
232 artak 2765 time0=Paso_timer()-time0;
233 artak 2784 if (verbose) fprintf(stdout,"timing: Coarsening: %e\n",time0);
234 artak 2760
235 artak 2686 #pragma omp parallel for private(i) schedule(static)
236     for (i = 0; i < n; ++i) counter[i]=mis_marker[i];
237 artak 2726
238 artak 2686 out->n_F=Paso_Util_cumsum(n,counter);
239    
240 artak 2726 if (out->n_F==0) {
241 artak 2686 out->coarsest_level=TRUE;
242 artak 2726 level=0;
243 artak 2686 if (verbose) {
244 artak 2726 /*printf("AMG coarsening eliminates all unknowns, switching to Jacobi preconditioner.\n");*/
245     printf("AMG coarsening does not eliminate any of the unknowns, switching to Jacobi preconditioner.\n");
246 artak 2686 }
247 artak 2726 }
248     else if (out->n_F==n) {
249     out->coarsest_level=TRUE;
250     level=0;
251     if (verbose) {
252     /*printf("AMG coarsening eliminates all unknowns, switching to Jacobi preconditioner.\n");*/
253     printf("AMG coarsening eliminates all of the unknowns, switching to Jacobi preconditioner.\n");
254    
255     }
256 artak 2686 } else {
257 artak 2475
258 artak 2686 if (Paso_noError()) {
259    
260     /*#pragma omp parallel for private(i) schedule(static)
261     for (i = 0; i < n; ++i) counter[i]=mis_marker[i];
262     out->n_F=Paso_Util_cumsum(n,counter);
263     */
264 artak 2760
265 artak 2686 out->mask_F=MEMALLOC(n,index_t);
266     out->rows_in_F=MEMALLOC(out->n_F,index_t);
267 artak 2760 if (! (Paso_checkPtr(out->mask_F) || Paso_checkPtr(out->rows_in_F) ) ) {
268 artak 2686 /* creates an index for F from mask */
269     #pragma omp parallel for private(i) schedule(static)
270     for (i = 0; i < out->n_F; ++i) out->rows_in_F[i]=-1;
271     #pragma omp parallel for private(i) schedule(static)
272     for (i = 0; i < n; ++i) {
273     if (mis_marker[i]) {
274     out->rows_in_F[counter[i]]=i;
275     out->mask_F[i]=counter[i];
276     } else {
277     out->mask_F[i]=-1;
278     }
279     }
280    
281 jfenwick 1851 }
282     }
283 artak 2686
284     /*check whether coarsening process actually makes sense to continue.
285     if coarse matrix at least smaller by 30% then continue, otherwise we stop.*/
286     if ((out->n_F*100/n)<30) {
287     level=1;
288 artak 1881 }
289 gross 2551
290 artak 2686 if ( Paso_noError()) {
291     /* if there are no nodes in the coarse level there is no more work to do */
292     out->n_C=n-out->n_F;
293    
294     /*if (out->n_F>500) */
295     out->rows_in_C=MEMALLOC(out->n_C,index_t);
296     out->mask_C=MEMALLOC(n,index_t);
297     if (! (Paso_checkPtr(out->mask_C) || Paso_checkPtr(out->rows_in_C) ) ) {
298     /* creates an index for C from mask */
299     #pragma omp parallel for private(i) schedule(static)
300     for (i = 0; i < n; ++i) counter[i]=! mis_marker[i];
301     Paso_Util_cumsum(n,counter);
302     #pragma omp parallel for private(i) schedule(static)
303     for (i = 0; i < out->n_C; ++i) out->rows_in_C[i]=-1;
304     #pragma omp parallel for private(i) schedule(static)
305     for (i = 0; i < n; ++i) {
306     if (! mis_marker[i]) {
307     out->rows_in_C[counter[i]]=i;
308     out->mask_C[i]=counter[i];
309     } else {
310     out->mask_C[i]=-1;
311     }
312     }
313     }
314     }
315     if ( Paso_noError()) {
316 artak 2760 /* get A_FF block: */
317     /*
318     out->A_FF=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_F,out->rows_in_F,out->mask_F);
319 artak 2686 out->A_CF=Paso_SparseMatrix_getSubmatrix(A_p,out->n_C,out->n_F,out->rows_in_C,out->mask_F);
320     out->A_FC=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_C,out->rows_in_F,out->mask_C);
321 artak 2760 */
322    
323     /*Compute W_FC*/
324     /*initialy W_FC=A_FC*/
325     out->W_FC=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_C,out->rows_in_F,out->mask_C);
326    
327     /*sprintf(filename,"W_FCbefore_%d",level);
328     Paso_SparseMatrix_saveMM(out->W_FC,filename);
329     */
330 artak 2784
331 artak 2765 time0=Paso_timer();
332 artak 2760 Paso_SparseMatrix_updateWeights(A_p,out->W_FC,mis_marker);
333 artak 2765 time0=Paso_timer()-time0;
334 artak 2784 if (verbose) fprintf(stdout,"timing: updateWeights: %e\n",time0);
335 artak 2765
336 artak 2760 /*
337     printf("GOT W_FC, but n=%d,n_F=%d,n_C=%d\n",out->n,out->n_F,out->n_C);
338     sprintf(filename,"W_FCafter_%d",level);
339     Paso_SparseMatrix_saveMM(out->W_FC,filename);
340     */
341     /* get Prolongation and Restriction */
342 artak 2765
343     time0=Paso_timer();
344 artak 2760 out->P=Paso_SparseMatrix_getProlongation(out->W_FC,mis_marker);
345 artak 2765 time0=Paso_timer()-time0;
346 artak 2784 if (verbose) fprintf(stdout,"timing: getProlongation: %e\n",time0);
347 artak 2760
348     /*
349     printf("GOT Prolongation P->nxc %dx%d\n",out->P->numRows,out->P->numCols);
350     sprintf(filename,"P_%d",level);
351     Paso_SparseMatrix_saveMM(out->P,filename);
352     */
353    
354 artak 2765 time0=Paso_timer();
355 artak 2760 out->R=Paso_SparseMatrix_getRestriction(out->P);
356 artak 2765 time0=Paso_timer()-time0;
357 artak 2784 if (verbose) fprintf(stdout,"timing: getRestriction: %e\n",time0);
358 artak 2765
359 artak 2760 /*
360     printf("GOT Restriction->cxn %dx%d\n",out->R->numRows,out->R->numCols);
361     sprintf(filename,"R_%d",level);
362     Paso_SparseMatrix_saveMM(out->R,filename);
363     */
364    
365 gross 2551 }
366 artak 2686 if ( Paso_noError()) {
367 artak 2765
368     time0=Paso_timer();
369 artak 2784
370     Atemp=Paso_SparseMatrix_MatrixMatrix(A_p,out->P);
371     A_c=Paso_SparseMatrix_MatrixMatrix(out->R,Atemp);
372    
373     Paso_SparseMatrix_free(Atemp);
374    
375     /*A_c=Paso_Solver_getCoarseMatrix(A_p,out->R,out->P);*/
376 artak 2765 time0=Paso_timer()-time0;
377 artak 2784 if (verbose) fprintf(stdout,"timing: getCoarseMatrix: %e\n",time0);
378 artak 2765
379 artak 2784
380 artak 2760 /*Paso_Solver_getCoarseMatrix(A_c, A_p,out->R,out->P);*/
381 artak 2767
382 artak 2784
383     /*sprintf(filename,"A_C_%d",level);
384 artak 2760 Paso_SparseMatrix_saveMM(A_c,filename);
385 artak 2767 */
386    
387 artak 2760 out->AMG_of_Coarse=Paso_Solver_getAMG(A_c,level-1,options);
388 gross 2551 }
389 artak 2760
390 artak 2686 /* allocate work arrays for AMG application */
391     if (Paso_noError()) {
392 artak 2767 /*
393     out->x_F=MEMALLOC(n_block*out->n_F,double);
394 artak 2686 out->b_F=MEMALLOC(n_block*out->n_F,double);
395 artak 2767 */
396 artak 2686 out->x_C=MEMALLOC(n_block*out->n_C,double);
397     out->b_C=MEMALLOC(n_block*out->n_C,double);
398    
399 artak 2767 /*if (! (Paso_checkPtr(out->x_F) || Paso_checkPtr(out->b_F) || Paso_checkPtr(out->x_C) || Paso_checkPtr(out->b_C) ) ) {*/
400     if ( ! ( Paso_checkPtr(out->x_C) || Paso_checkPtr(out->b_C) ) ) {
401    
402     /*
403     #pragma omp parallel for private(i) schedule(static)
404 artak 2686 for (i = 0; i < out->n_F; ++i) {
405     out->x_F[i]=0.;
406     out->b_F[i]=0.;
407     }
408 artak 2767 */
409    
410 artak 2686 #pragma omp parallel for private(i) schedule(static)
411     for (i = 0; i < out->n_C; ++i) {
412     out->x_C[i]=0.;
413     out->b_C[i]=0.;
414     }
415     }
416     }
417 artak 2760 Paso_SparseMatrix_free(A_c);
418 artak 2686 }
419 jfenwick 1851 }
420     }
421     TMPMEMFREE(mis_marker);
422     TMPMEMFREE(counter);
423 artak 2686
424 jfenwick 1851 if (Paso_noError()) {
425 artak 2524 if (verbose && level>0 && !out->coarsest_level) {
426 gross 2551 printf("AMG: level: %d: %d unknowns eliminated. %d left.\n",level, out->n_F,out->n_C);
427 jfenwick 1851 }
428     return out;
429     } else {
430     Paso_Solver_AMG_free(out);
431     return NULL;
432     }
433     }
434    
435     /**************************************************************/
436    
437     /* apply AMG precondition b-> x
438    
439     in fact it solves
440    
441 artak 2381 [ I 0 ] [ A_FF 0 ] [ I invA_FF*A_FC ] [ x_F ] = [b_F]
442 jfenwick 1851 [ A_CF*invA_FF I ] [ 0 S ] [ 0 I ] [ x_C ] = [b_C]
443    
444     in the form
445    
446     b->[b_F,b_C]
447     x_F=invA_FF*b_F
448     b_C=b_C-A_CF*x_F
449     x_C=AMG(b_C)
450     b_F=b_F-A_FC*x_C
451     x_F=invA_FF*b_F
452     x<-[x_F,x_C]
453    
454     should be called within a parallel region
455     barrier synconization should be performed to make sure that the input vector available
456    
457     */
458    
459     void Paso_Solver_solveAMG(Paso_Solver_AMG * amg, double * x, double * b) {
460 artak 2107 dim_t i;
461 artak 2507 double time0=0;
462 gross 2551 double *r=NULL, *x0=NULL;
463 artak 2509 bool_t verbose=0;
464 artak 2784
465 artak 2699 #ifdef UMFPACK
466     Paso_UMFPACK_Handler * ptr=NULL;
467 artak 2507 #endif
468 artak 2760
469 artak 2784
470 gross 2551 r=MEMALLOC(amg->n,double);
471     x0=MEMALLOC(amg->n,double);
472 artak 2507
473 artak 2524 if (amg->coarsest_level) {
474 artak 2507
475     time0=Paso_timer();
476 artak 2699 /*If all unknown are eliminated then Jacobi is the best preconditioner*/
477 artak 2784 /*Paso_Solver_solveJacobi(amg->GS,x,b);*/
478    
479 artak 2726 if (amg->n_F==0 || amg->n_F==amg->n) {
480 artak 2699 Paso_Solver_solveJacobi(amg->GS,x,b);
481     }
482     else {
483 artak 2712 #ifdef MKL
484     Paso_MKL1(amg->AOffset1,x,b,verbose);
485     #else
486     #ifdef UMFPACK
487 gross 2551 ptr=(Paso_UMFPACK_Handler *)(amg->solver);
488 artak 2652 Paso_UMFPACK1(&ptr,amg->A,x,b,verbose);
489 gross 2551 amg->solver=(void*) ptr;
490 artak 2712 #else
491     Paso_Solver_solveJacobi(amg->GS,x,b);
492 artak 2699 #endif
493 artak 2507 #endif
494 artak 2699 }
495 artak 2784
496 artak 2475 time0=Paso_timer()-time0;
497 artak 2784 if (verbose) fprintf(stdout,"timing: DIRECT SOLVER: %e\n",time0);
498 artak 2507
499 jfenwick 1851 } else {
500 artak 1902 /* presmoothing */
501 artak 2507 time0=Paso_timer();
502 artak 2112 Paso_Solver_solveJacobi(amg->GS,x,b);
503 artak 2507 time0=Paso_timer()-time0;
504 artak 2784 if (verbose) fprintf(stdout,"timing: Presmooting: %e\n",time0);
505 artak 1931 /* end of presmoothing */
506 artak 1939
507 artak 2507
508     time0=Paso_timer();
509 artak 1890 #pragma omp parallel for private(i) schedule(static)
510     for (i=0;i<amg->n;++i) r[i]=b[i];
511    
512     /*r=b-Ax*/
513     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
514 artak 2760
515    
516     /* b_c <- R*r */
517     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(1.,amg->R,r,0.,amg->b_C);
518 artak 1954
519 artak 2507 time0=Paso_timer()-time0;
520 artak 2784 if (verbose) fprintf(stdout,"timing: Before next level: %e\n",time0);
521 artak 2507
522 jfenwick 1851 /* x_C=AMG(b_C) */
523 artak 2760 Paso_Solver_solveAMG(amg->AMG_of_Coarse,amg->x_C,amg->b_C);
524 artak 1890
525 artak 2507 time0=Paso_timer();
526 artak 2726
527 artak 2760 /* x_0 <- P*x_c */
528     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(1.,amg->P,amg->x_C,0.,x0);
529    
530     /* x=x+x0 */
531 artak 1954 #pragma omp parallel for private(i) schedule(static)
532 artak 2760 for (i=0;i<amg->n;++i) x[i]+=x0[i];
533 artak 1954
534 artak 2767 /*postsmoothing*/
535     time0=Paso_timer();
536     #pragma omp parallel for private(i) schedule(static)
537     for (i=0;i<amg->n;++i) r[i]=b[i];
538    
539     /*r=b-Ax */
540     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
541     Paso_Solver_solveJacobi(amg->GS,x0,r);
542    
543    
544     #pragma omp parallel for private(i) schedule(static)
545     for (i=0;i<amg->n;++i) {
546     x[i]+=x0[i];
547     /*printf("x[%d]=%e \n",i,x[i]);*/
548     }
549    
550     time0=Paso_timer()-time0;
551 artak 2784 if (verbose) fprintf(stdout,"timing: Postsmoothing: %e\n",time0);
552 artak 2767
553     /*end of postsmoothing*/
554 artak 2107
555 artak 2760 }
556 artak 1890 MEMFREE(r);
557 artak 1954 MEMFREE(x0);
558 artak 2760
559 gross 2551 return;
560 jfenwick 1851 }

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