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

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Revision 2803 - (hide annotations)
Thu Dec 3 05:35:20 2009 UTC (10 years, 2 months ago) by artak
File MIME type: text/plain
File size: 21244 byte(s)
Parameters are added for post and pre smoothing. Now user can choose number of pre and post smoothing steps in AMG (e.g. setNumPreSweeps(5)). 
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     /*char filename[8];*/
130     /*sprintf(filename,"AMGLevel%d",level);
131 artak 2726
132 artak 2760 Paso_SparseMatrix_saveMM(A_p,filename);
133 artak 2726 */
134    
135 artak 2439 /*Make sure we have block sizes 1*/
136 gross 2550 if (A_p->col_block_size>1) {
137     Paso_setError(TYPE_ERROR,"Paso_Solver_getAMG: AMG requires column block size 1.");
138     return NULL;
139     }
140     if (A_p->row_block_size>1) {
141     Paso_setError(TYPE_ERROR,"Paso_Solver_getAMG: AMG requires row block size 1.");
142     return NULL;
143     }
144 gross 2551 out=MEMALLOC(1,Paso_Solver_AMG);
145 jfenwick 1851 /* identify independend set of rows/columns */
146     mis_marker=TMPMEMALLOC(n,index_t);
147     counter=TMPMEMALLOC(n,index_t);
148 gross 2551 if ( !( Paso_checkPtr(mis_marker) || Paso_checkPtr(counter) || Paso_checkPtr(out)) ) {
149 artak 2760 out->AMG_of_Coarse=NULL;
150     out->A_FF=NULL;
151 gross 2551 out->A_FC=NULL;
152     out->A_CF=NULL;
153 artak 2760 out->W_FC=NULL;
154     out->P=NULL;
155     out->R=NULL;
156 gross 2551 out->rows_in_F=NULL;
157     out->rows_in_C=NULL;
158     out->mask_F=NULL;
159     out->mask_C=NULL;
160     out->x_F=NULL;
161     out->b_F=NULL;
162     out->x_C=NULL;
163     out->b_C=NULL;
164     out->GS=NULL;
165     out->A=Paso_SparseMatrix_getReference(A_p);
166     out->GS=NULL;
167     out->solver=NULL;
168     /*out->GS=Paso_Solver_getGS(A_p,verbose);*/
169     out->level=level;
170 artak 2661 out->n=n;
171 artak 2726 out->n_F=n+1;
172 artak 2661 out->n_block=n_block;
173 artak 2803 out->post_sweeps=options->post_sweeps;
174     out->pre_sweeps=options->pre_sweeps;
175 artak 2556
176 artak 2784 sparsity=(A_p->len*1.)/(1.*A_p->numRows*A_p->numCols);
177    
178     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);
179    
180 artak 2802
181 artak 2803 /*if(sparsity>0.01) {
182 artak 2784 level=0;
183     }
184 artak 2803 */
185 artak 2802
186 gross 2551 if (level==0 || n<=options->min_coarse_matrix_size) {
187     out->coarsest_level=TRUE;
188 artak 2784 /*out->GS=Paso_Solver_getJacobi(A_p);*/
189    
190 artak 2712 #ifdef MKL
191 artak 2711 out->AOffset1=Paso_SparseMatrix_alloc(MATRIX_FORMAT_BLK1 + MATRIX_FORMAT_OFFSET1, out->A->pattern,1,1, FALSE);
192     #pragma omp parallel for private(i) schedule(static)
193     for (i=0;i<out->A->len;++i) {
194     out->AOffset1->val[i]=out->A->val[i];
195     }
196 artak 2712 #else
197     #ifdef UMFPACK
198     #else
199 gross 2551 out->GS=Paso_Solver_getJacobi(A_p);
200     #endif
201     #endif
202 artak 2784
203 gross 2551 } else {
204     out->coarsest_level=FALSE;
205     out->GS=Paso_Solver_getJacobi(A_p);
206 artak 2442
207 gross 2551 /* identify independend set of rows/columns */
208     #pragma omp parallel for private(i) schedule(static)
209     for (i=0;i<n;++i) mis_marker[i]=-1;
210    
211 artak 2765 /*mesuring coarsening time */
212     time0=Paso_timer();
213    
214 gross 2551 if (options->coarsening_method == PASO_YAIR_SHAPIRA_COARSENING) {
215 artak 2652 Paso_Pattern_YS(A_p,mis_marker,options->coarsening_threshold);
216 gross 2551 }
217     else if (options->coarsening_method == PASO_RUGE_STUEBEN_COARSENING) {
218     Paso_Pattern_RS(A_p,mis_marker,options->coarsening_threshold);
219     }
220     else if (options->coarsening_method == PASO_AGGREGATION_COARSENING) {
221     Paso_Pattern_Aggregiation(A_p,mis_marker,options->coarsening_threshold);
222     }
223     else {
224     /*Default coarseneing*/
225 artak 2803 Paso_Pattern_RS_MI_Aggressive(A_p,mis_marker,options->coarsening_threshold);
226     /*Paso_Pattern_RS_MI(A_p,mis_marker,options->coarsening_threshold);*/
227 artak 2659 /*Paso_Pattern_YS(A_p,mis_marker,options->coarsening_threshold);*/
228 artak 2760 /*Paso_Pattern_RS(A_p,mis_marker,options->coarsening_threshold);*/
229 artak 2726 /*Paso_Pattern_Aggregiation(A_p,mis_marker,options->coarsening_threshold);*/
230 artak 2760
231 gross 2551 }
232 artak 2765
233 artak 2784 if (verbose) fprintf(stdout,"timing: Profilining for level %d:\n",level);
234 artak 2767
235 artak 2765 time0=Paso_timer()-time0;
236 artak 2784 if (verbose) fprintf(stdout,"timing: Coarsening: %e\n",time0);
237 artak 2760
238 artak 2686 #pragma omp parallel for private(i) schedule(static)
239     for (i = 0; i < n; ++i) counter[i]=mis_marker[i];
240 artak 2726
241 artak 2686 out->n_F=Paso_Util_cumsum(n,counter);
242    
243 artak 2726 if (out->n_F==0) {
244 artak 2686 out->coarsest_level=TRUE;
245 artak 2726 level=0;
246 artak 2686 if (verbose) {
247 artak 2726 /*printf("AMG coarsening eliminates all unknowns, switching to Jacobi preconditioner.\n");*/
248     printf("AMG coarsening does not eliminate any of the unknowns, switching to Jacobi preconditioner.\n");
249 artak 2686 }
250 artak 2726 }
251     else if (out->n_F==n) {
252     out->coarsest_level=TRUE;
253     level=0;
254     if (verbose) {
255     /*printf("AMG coarsening eliminates all unknowns, switching to Jacobi preconditioner.\n");*/
256     printf("AMG coarsening eliminates all of the unknowns, switching to Jacobi preconditioner.\n");
257    
258     }
259 artak 2686 } else {
260 artak 2475
261 artak 2686 if (Paso_noError()) {
262    
263     /*#pragma omp parallel for private(i) schedule(static)
264     for (i = 0; i < n; ++i) counter[i]=mis_marker[i];
265     out->n_F=Paso_Util_cumsum(n,counter);
266     */
267 artak 2760
268 artak 2686 out->mask_F=MEMALLOC(n,index_t);
269     out->rows_in_F=MEMALLOC(out->n_F,index_t);
270 artak 2760 if (! (Paso_checkPtr(out->mask_F) || Paso_checkPtr(out->rows_in_F) ) ) {
271 artak 2686 /* creates an index for F from mask */
272     #pragma omp parallel for private(i) schedule(static)
273     for (i = 0; i < out->n_F; ++i) out->rows_in_F[i]=-1;
274     #pragma omp parallel for private(i) schedule(static)
275     for (i = 0; i < n; ++i) {
276     if (mis_marker[i]) {
277     out->rows_in_F[counter[i]]=i;
278     out->mask_F[i]=counter[i];
279     } else {
280     out->mask_F[i]=-1;
281     }
282     }
283    
284 jfenwick 1851 }
285     }
286 artak 2802
287     /*if(level==1) {
288     printf("##TOTAL: %d, ELIMINATED: %d\n",n,out->n_F);
289     for (i = 0; i < n; ++i) {
290     printf("##%d %d\n",i,mis_marker[i]);
291     }
292     }
293     */
294 artak 2686 /*check whether coarsening process actually makes sense to continue.
295     if coarse matrix at least smaller by 30% then continue, otherwise we stop.*/
296     if ((out->n_F*100/n)<30) {
297     level=1;
298 artak 1881 }
299 gross 2551
300 artak 2686 if ( Paso_noError()) {
301     out->n_C=n-out->n_F;
302     out->rows_in_C=MEMALLOC(out->n_C,index_t);
303     out->mask_C=MEMALLOC(n,index_t);
304     if (! (Paso_checkPtr(out->mask_C) || Paso_checkPtr(out->rows_in_C) ) ) {
305     /* creates an index for C from mask */
306     #pragma omp parallel for private(i) schedule(static)
307     for (i = 0; i < n; ++i) counter[i]=! mis_marker[i];
308     Paso_Util_cumsum(n,counter);
309     #pragma omp parallel for private(i) schedule(static)
310     for (i = 0; i < out->n_C; ++i) out->rows_in_C[i]=-1;
311     #pragma omp parallel for private(i) schedule(static)
312     for (i = 0; i < n; ++i) {
313     if (! mis_marker[i]) {
314     out->rows_in_C[counter[i]]=i;
315     out->mask_C[i]=counter[i];
316     } else {
317     out->mask_C[i]=-1;
318     }
319     }
320     }
321     }
322     if ( Paso_noError()) {
323 artak 2760 /* get A_FF block: */
324     /*
325     out->A_FF=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_F,out->rows_in_F,out->mask_F);
326 artak 2686 out->A_CF=Paso_SparseMatrix_getSubmatrix(A_p,out->n_C,out->n_F,out->rows_in_C,out->mask_F);
327     out->A_FC=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_C,out->rows_in_F,out->mask_C);
328 artak 2760 */
329    
330     /*Compute W_FC*/
331     /*initialy W_FC=A_FC*/
332     out->W_FC=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_C,out->rows_in_F,out->mask_C);
333    
334     /*sprintf(filename,"W_FCbefore_%d",level);
335     Paso_SparseMatrix_saveMM(out->W_FC,filename);
336     */
337 artak 2802 /* for (i = 0; i < n; ++i) {
338     printf("##mis_marker[%d]=%d\n",i,mis_marker[i]);
339     }
340     */
341 artak 2765 time0=Paso_timer();
342 artak 2760 Paso_SparseMatrix_updateWeights(A_p,out->W_FC,mis_marker);
343 artak 2765 time0=Paso_timer()-time0;
344 artak 2784 if (verbose) fprintf(stdout,"timing: updateWeights: %e\n",time0);
345 artak 2765
346 artak 2802
347     /*sprintf(filename,"W_FCafter_%d",level);
348 artak 2760 Paso_SparseMatrix_saveMM(out->W_FC,filename);
349     */
350 artak 2802
351 artak 2760 /* get Prolongation and Restriction */
352 artak 2765 time0=Paso_timer();
353 artak 2760 out->P=Paso_SparseMatrix_getProlongation(out->W_FC,mis_marker);
354 artak 2765 time0=Paso_timer()-time0;
355 artak 2784 if (verbose) fprintf(stdout,"timing: getProlongation: %e\n",time0);
356 artak 2760
357 artak 2802
358    
359     /* sprintf(filename,"P_%d",level);
360 artak 2760 Paso_SparseMatrix_saveMM(out->P,filename);
361     */
362    
363 artak 2765 time0=Paso_timer();
364 artak 2760 out->R=Paso_SparseMatrix_getRestriction(out->P);
365 artak 2765 time0=Paso_timer()-time0;
366 artak 2784 if (verbose) fprintf(stdout,"timing: getRestriction: %e\n",time0);
367 artak 2765
368 artak 2802
369     /*sprintf(filename,"R_%d",level);
370 artak 2760 Paso_SparseMatrix_saveMM(out->R,filename);
371     */
372    
373 gross 2551 }
374 artak 2686 if ( Paso_noError()) {
375 artak 2765
376     time0=Paso_timer();
377 artak 2784
378     Atemp=Paso_SparseMatrix_MatrixMatrix(A_p,out->P);
379     A_c=Paso_SparseMatrix_MatrixMatrix(out->R,Atemp);
380    
381     Paso_SparseMatrix_free(Atemp);
382    
383     /*A_c=Paso_Solver_getCoarseMatrix(A_p,out->R,out->P);*/
384 artak 2765 time0=Paso_timer()-time0;
385 artak 2784 if (verbose) fprintf(stdout,"timing: getCoarseMatrix: %e\n",time0);
386 artak 2765
387 artak 2784
388 artak 2760 /*Paso_Solver_getCoarseMatrix(A_c, A_p,out->R,out->P);*/
389 artak 2767
390 artak 2784
391     /*sprintf(filename,"A_C_%d",level);
392 artak 2760 Paso_SparseMatrix_saveMM(A_c,filename);
393 artak 2767 */
394    
395 artak 2760 out->AMG_of_Coarse=Paso_Solver_getAMG(A_c,level-1,options);
396 gross 2551 }
397 artak 2760
398 artak 2686 /* allocate work arrays for AMG application */
399     if (Paso_noError()) {
400 artak 2767 /*
401     out->x_F=MEMALLOC(n_block*out->n_F,double);
402 artak 2686 out->b_F=MEMALLOC(n_block*out->n_F,double);
403 artak 2767 */
404 artak 2686 out->x_C=MEMALLOC(n_block*out->n_C,double);
405     out->b_C=MEMALLOC(n_block*out->n_C,double);
406    
407 artak 2767 /*if (! (Paso_checkPtr(out->x_F) || Paso_checkPtr(out->b_F) || Paso_checkPtr(out->x_C) || Paso_checkPtr(out->b_C) ) ) {*/
408     if ( ! ( Paso_checkPtr(out->x_C) || Paso_checkPtr(out->b_C) ) ) {
409    
410     /*
411     #pragma omp parallel for private(i) schedule(static)
412 artak 2686 for (i = 0; i < out->n_F; ++i) {
413     out->x_F[i]=0.;
414     out->b_F[i]=0.;
415     }
416 artak 2767 */
417    
418 artak 2686 #pragma omp parallel for private(i) schedule(static)
419     for (i = 0; i < out->n_C; ++i) {
420     out->x_C[i]=0.;
421     out->b_C[i]=0.;
422     }
423     }
424     }
425 artak 2760 Paso_SparseMatrix_free(A_c);
426 artak 2686 }
427 jfenwick 1851 }
428     }
429     TMPMEMFREE(mis_marker);
430     TMPMEMFREE(counter);
431 artak 2686
432 jfenwick 1851 if (Paso_noError()) {
433 artak 2524 if (verbose && level>0 && !out->coarsest_level) {
434 gross 2551 printf("AMG: level: %d: %d unknowns eliminated. %d left.\n",level, out->n_F,out->n_C);
435 jfenwick 1851 }
436     return out;
437     } else {
438     Paso_Solver_AMG_free(out);
439     return NULL;
440     }
441     }
442    
443     /**************************************************************/
444    
445     /* apply AMG precondition b-> x
446    
447     in fact it solves
448    
449 artak 2381 [ I 0 ] [ A_FF 0 ] [ I invA_FF*A_FC ] [ x_F ] = [b_F]
450 jfenwick 1851 [ A_CF*invA_FF I ] [ 0 S ] [ 0 I ] [ x_C ] = [b_C]
451    
452     in the form
453    
454     b->[b_F,b_C]
455     x_F=invA_FF*b_F
456     b_C=b_C-A_CF*x_F
457     x_C=AMG(b_C)
458     b_F=b_F-A_FC*x_C
459     x_F=invA_FF*b_F
460     x<-[x_F,x_C]
461    
462     should be called within a parallel region
463     barrier synconization should be performed to make sure that the input vector available
464    
465     */
466    
467     void Paso_Solver_solveAMG(Paso_Solver_AMG * amg, double * x, double * b) {
468 artak 2107 dim_t i;
469 artak 2507 double time0=0;
470 gross 2551 double *r=NULL, *x0=NULL;
471 artak 2509 bool_t verbose=0;
472 artak 2784
473 artak 2803 dim_t post_sweeps=amg->post_sweeps;
474     dim_t pre_sweeps=amg->pre_sweeps;
475    
476 artak 2699 #ifdef UMFPACK
477     Paso_UMFPACK_Handler * ptr=NULL;
478 artak 2507 #endif
479 artak 2760
480 artak 2784
481 gross 2551 r=MEMALLOC(amg->n,double);
482     x0=MEMALLOC(amg->n,double);
483 artak 2507
484 artak 2524 if (amg->coarsest_level) {
485 artak 2507
486     time0=Paso_timer();
487 artak 2699 /*If all unknown are eliminated then Jacobi is the best preconditioner*/
488 artak 2784 /*Paso_Solver_solveJacobi(amg->GS,x,b);*/
489    
490 artak 2726 if (amg->n_F==0 || amg->n_F==amg->n) {
491 artak 2699 Paso_Solver_solveJacobi(amg->GS,x,b);
492     }
493     else {
494 artak 2712 #ifdef MKL
495     Paso_MKL1(amg->AOffset1,x,b,verbose);
496     #else
497     #ifdef UMFPACK
498 gross 2551 ptr=(Paso_UMFPACK_Handler *)(amg->solver);
499 artak 2652 Paso_UMFPACK1(&ptr,amg->A,x,b,verbose);
500 gross 2551 amg->solver=(void*) ptr;
501 artak 2712 #else
502     Paso_Solver_solveJacobi(amg->GS,x,b);
503 artak 2699 #endif
504 artak 2507 #endif
505 artak 2699 }
506 artak 2784
507 artak 2475 time0=Paso_timer()-time0;
508 artak 2784 if (verbose) fprintf(stdout,"timing: DIRECT SOLVER: %e\n",time0);
509 artak 2507
510 jfenwick 1851 } else {
511 artak 1902 /* presmoothing */
512 artak 2507 time0=Paso_timer();
513 artak 2112 Paso_Solver_solveJacobi(amg->GS,x,b);
514 artak 2803
515     /***********/
516     #pragma omp parallel for private(i) schedule(static)
517     for (i=0;i<amg->n;++i) r[i]=b[i];
518    
519     while(pre_sweeps>1) {
520     #pragma omp parallel for private(i) schedule(static)
521     for (i=0;i<amg->n;++i) r[i]+=b[i];
522    
523     /* Compute the residual b=b-Ax*/
524     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
525     /* Go round again*/
526     Paso_Solver_solveJacobi(amg->GS,x,r);
527     pre_sweeps-=1;
528     }
529     /***********/
530    
531 artak 2507 time0=Paso_timer()-time0;
532 artak 2784 if (verbose) fprintf(stdout,"timing: Presmooting: %e\n",time0);
533 artak 2803 /* end of presmoothing */
534 artak 1939
535 artak 2507 time0=Paso_timer();
536 artak 1890 #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 artak 2760
542     /* b_c <- R*r */
543     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(1.,amg->R,r,0.,amg->b_C);
544 artak 1954
545 artak 2507 time0=Paso_timer()-time0;
546 artak 2784 if (verbose) fprintf(stdout,"timing: Before next level: %e\n",time0);
547 artak 2507
548 jfenwick 1851 /* x_C=AMG(b_C) */
549 artak 2760 Paso_Solver_solveAMG(amg->AMG_of_Coarse,amg->x_C,amg->b_C);
550 artak 1890
551 artak 2507 time0=Paso_timer();
552 artak 2726
553 artak 2760 /* x_0 <- P*x_c */
554     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(1.,amg->P,amg->x_C,0.,x0);
555    
556     /* x=x+x0 */
557 artak 1954 #pragma omp parallel for private(i) schedule(static)
558 artak 2760 for (i=0;i<amg->n;++i) x[i]+=x0[i];
559 artak 1954
560 artak 2767 /*postsmoothing*/
561 artak 2803
562 artak 2767 time0=Paso_timer();
563     #pragma omp parallel for private(i) schedule(static)
564     for (i=0;i<amg->n;++i) r[i]=b[i];
565    
566     /*r=b-Ax */
567     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
568     Paso_Solver_solveJacobi(amg->GS,x0,r);
569    
570    
571     #pragma omp parallel for private(i) schedule(static)
572     for (i=0;i<amg->n;++i) {
573     x[i]+=x0[i];
574     }
575 artak 2803 /***************/
576     while(post_sweeps>1) {
577    
578     #pragma omp parallel for private(i) schedule(static)
579     for (i=0;i<amg->n;++i) r[i]=b[i];
580    
581     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
582     Paso_Solver_solveJacobi(amg->GS,x0,r);
583     #pragma omp parallel for private(i) schedule(static)
584     for (i=0;i<amg->n;++i) {
585     x[i]+=x0[i];
586     }
587     post_sweeps-=1;
588     }
589     /**************/
590 artak 2767
591     time0=Paso_timer()-time0;
592 artak 2784 if (verbose) fprintf(stdout,"timing: Postsmoothing: %e\n",time0);
593 artak 2767
594     /*end of postsmoothing*/
595 artak 2107
596 artak 2760 }
597 artak 1890 MEMFREE(r);
598 artak 1954 MEMFREE(x0);
599 artak 2760
600 gross 2551 return;
601 jfenwick 1851 }

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