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

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Revision 2816 - (hide annotations)
Thu Dec 10 02:09:43 2009 UTC (10 years, 2 months ago) by artak
File MIME type: text/plain
File size: 21516 byte(s)
Standard coarsening is added to options list.
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->solver=NULL;
167     /*out->GS=Paso_Solver_getGS(A_p,verbose);*/
168     out->level=level;
169 artak 2661 out->n=n;
170 artak 2726 out->n_F=n+1;
171 artak 2661 out->n_block=n_block;
172 artak 2803 out->post_sweeps=options->post_sweeps;
173     out->pre_sweeps=options->pre_sweeps;
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 artak 2802
180 artak 2803 /*if(sparsity>0.01) {
181 artak 2784 level=0;
182     }
183 artak 2803 */
184 artak 2802
185 gross 2551 if (level==0 || n<=options->min_coarse_matrix_size) {
186     out->coarsest_level=TRUE;
187 artak 2784 /*out->GS=Paso_Solver_getJacobi(A_p);*/
188    
189 artak 2712 #ifdef MKL
190 artak 2711 out->AOffset1=Paso_SparseMatrix_alloc(MATRIX_FORMAT_BLK1 + MATRIX_FORMAT_OFFSET1, out->A->pattern,1,1, FALSE);
191     #pragma omp parallel for private(i) schedule(static)
192     for (i=0;i<out->A->len;++i) {
193     out->AOffset1->val[i]=out->A->val[i];
194     }
195 artak 2712 #else
196     #ifdef UMFPACK
197     #else
198 gross 2551 out->GS=Paso_Solver_getJacobi(A_p);
199     #endif
200     #endif
201 artak 2784
202 gross 2551 } else {
203     out->coarsest_level=FALSE;
204     out->GS=Paso_Solver_getJacobi(A_p);
205 artak 2442
206 gross 2551 /* identify independend set of rows/columns */
207     #pragma omp parallel for private(i) schedule(static)
208     for (i=0;i<n;++i) mis_marker[i]=-1;
209    
210 artak 2765 /*mesuring coarsening time */
211     time0=Paso_timer();
212    
213 gross 2551 if (options->coarsening_method == PASO_YAIR_SHAPIRA_COARSENING) {
214 artak 2652 Paso_Pattern_YS(A_p,mis_marker,options->coarsening_threshold);
215 gross 2551 }
216     else if (options->coarsening_method == PASO_RUGE_STUEBEN_COARSENING) {
217     Paso_Pattern_RS(A_p,mis_marker,options->coarsening_threshold);
218     }
219     else if (options->coarsening_method == PASO_AGGREGATION_COARSENING) {
220     Paso_Pattern_Aggregiation(A_p,mis_marker,options->coarsening_threshold);
221     }
222 artak 2816 else if (options->coarsening_method == PASO_STANDARD_COARSENING) {
223     Paso_Pattern_Standard(A_p,mis_marker,options->coarsening_threshold);
224     }
225 gross 2551 else {
226     /*Default coarseneing*/
227 artak 2816 /*Paso_Pattern_RS_MI_Aggressive(A_p,mis_marker,options->coarsening_threshold);*/
228     Paso_Pattern_Standard(A_p,mis_marker,options->coarsening_threshold);
229 artak 2659 /*Paso_Pattern_YS(A_p,mis_marker,options->coarsening_threshold);*/
230 artak 2760 /*Paso_Pattern_RS(A_p,mis_marker,options->coarsening_threshold);*/
231 artak 2816 /*Paso_Pattern_greedy(A_p->pattern,mis_marker);*/
232 artak 2726 /*Paso_Pattern_Aggregiation(A_p,mis_marker,options->coarsening_threshold);*/
233 artak 2760
234 gross 2551 }
235 artak 2765
236 artak 2784 if (verbose) fprintf(stdout,"timing: Profilining for level %d:\n",level);
237 artak 2767
238 artak 2765 time0=Paso_timer()-time0;
239 artak 2784 if (verbose) fprintf(stdout,"timing: Coarsening: %e\n",time0);
240 artak 2760
241 artak 2686 #pragma omp parallel for private(i) schedule(static)
242     for (i = 0; i < n; ++i) counter[i]=mis_marker[i];
243 artak 2726
244 artak 2686 out->n_F=Paso_Util_cumsum(n,counter);
245    
246 artak 2726 if (out->n_F==0) {
247 artak 2686 out->coarsest_level=TRUE;
248 artak 2726 level=0;
249 artak 2686 if (verbose) {
250 artak 2726 /*printf("AMG coarsening eliminates all unknowns, switching to Jacobi preconditioner.\n");*/
251     printf("AMG coarsening does not eliminate any of the unknowns, switching to Jacobi preconditioner.\n");
252 artak 2686 }
253 artak 2726 }
254     else if (out->n_F==n) {
255     out->coarsest_level=TRUE;
256     level=0;
257     if (verbose) {
258     /*printf("AMG coarsening eliminates all unknowns, switching to Jacobi preconditioner.\n");*/
259     printf("AMG coarsening eliminates all of the unknowns, switching to Jacobi preconditioner.\n");
260    
261     }
262 artak 2686 } else {
263 artak 2475
264 artak 2686 if (Paso_noError()) {
265    
266     /*#pragma omp parallel for private(i) schedule(static)
267     for (i = 0; i < n; ++i) counter[i]=mis_marker[i];
268     out->n_F=Paso_Util_cumsum(n,counter);
269     */
270 artak 2760
271 artak 2686 out->mask_F=MEMALLOC(n,index_t);
272     out->rows_in_F=MEMALLOC(out->n_F,index_t);
273 artak 2760 if (! (Paso_checkPtr(out->mask_F) || Paso_checkPtr(out->rows_in_F) ) ) {
274 artak 2686 /* creates an index for F from mask */
275     #pragma omp parallel for private(i) schedule(static)
276     for (i = 0; i < out->n_F; ++i) out->rows_in_F[i]=-1;
277     #pragma omp parallel for private(i) schedule(static)
278     for (i = 0; i < n; ++i) {
279     if (mis_marker[i]) {
280     out->rows_in_F[counter[i]]=i;
281     out->mask_F[i]=counter[i];
282     } else {
283     out->mask_F[i]=-1;
284     }
285     }
286    
287 jfenwick 1851 }
288     }
289 artak 2802
290 artak 2816 /* if(level==1) {
291 artak 2802 printf("##TOTAL: %d, ELIMINATED: %d\n",n,out->n_F);
292     for (i = 0; i < n; ++i) {
293     printf("##%d %d\n",i,mis_marker[i]);
294     }
295 artak 2816 }
296     */
297    
298 artak 2686 /*check whether coarsening process actually makes sense to continue.
299     if coarse matrix at least smaller by 30% then continue, otherwise we stop.*/
300     if ((out->n_F*100/n)<30) {
301     level=1;
302 artak 1881 }
303 gross 2551
304 artak 2686 if ( Paso_noError()) {
305     out->n_C=n-out->n_F;
306     out->rows_in_C=MEMALLOC(out->n_C,index_t);
307     out->mask_C=MEMALLOC(n,index_t);
308     if (! (Paso_checkPtr(out->mask_C) || Paso_checkPtr(out->rows_in_C) ) ) {
309     /* creates an index for C from mask */
310     #pragma omp parallel for private(i) schedule(static)
311     for (i = 0; i < n; ++i) counter[i]=! mis_marker[i];
312     Paso_Util_cumsum(n,counter);
313     #pragma omp parallel for private(i) schedule(static)
314     for (i = 0; i < out->n_C; ++i) out->rows_in_C[i]=-1;
315     #pragma omp parallel for private(i) schedule(static)
316     for (i = 0; i < n; ++i) {
317     if (! mis_marker[i]) {
318     out->rows_in_C[counter[i]]=i;
319     out->mask_C[i]=counter[i];
320     } else {
321     out->mask_C[i]=-1;
322     }
323     }
324     }
325     }
326     if ( Paso_noError()) {
327 artak 2760 /* get A_FF block: */
328     /*
329     out->A_FF=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_F,out->rows_in_F,out->mask_F);
330 artak 2686 out->A_CF=Paso_SparseMatrix_getSubmatrix(A_p,out->n_C,out->n_F,out->rows_in_C,out->mask_F);
331     out->A_FC=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_C,out->rows_in_F,out->mask_C);
332 artak 2760 */
333    
334     /*Compute W_FC*/
335     /*initialy W_FC=A_FC*/
336     out->W_FC=Paso_SparseMatrix_getSubmatrix(A_p,out->n_F,out->n_C,out->rows_in_F,out->mask_C);
337    
338     /*sprintf(filename,"W_FCbefore_%d",level);
339     Paso_SparseMatrix_saveMM(out->W_FC,filename);
340     */
341 artak 2802 /* for (i = 0; i < n; ++i) {
342     printf("##mis_marker[%d]=%d\n",i,mis_marker[i]);
343     }
344     */
345 artak 2765 time0=Paso_timer();
346 artak 2760 Paso_SparseMatrix_updateWeights(A_p,out->W_FC,mis_marker);
347 artak 2765 time0=Paso_timer()-time0;
348 artak 2784 if (verbose) fprintf(stdout,"timing: updateWeights: %e\n",time0);
349 artak 2765
350 artak 2802
351     /*sprintf(filename,"W_FCafter_%d",level);
352 artak 2760 Paso_SparseMatrix_saveMM(out->W_FC,filename);
353     */
354 artak 2802
355 artak 2760 /* get Prolongation and Restriction */
356 artak 2765 time0=Paso_timer();
357 artak 2760 out->P=Paso_SparseMatrix_getProlongation(out->W_FC,mis_marker);
358 artak 2765 time0=Paso_timer()-time0;
359 artak 2784 if (verbose) fprintf(stdout,"timing: getProlongation: %e\n",time0);
360 artak 2760
361 artak 2802
362    
363     /* sprintf(filename,"P_%d",level);
364 artak 2760 Paso_SparseMatrix_saveMM(out->P,filename);
365     */
366    
367 artak 2765 time0=Paso_timer();
368 artak 2760 out->R=Paso_SparseMatrix_getRestriction(out->P);
369 artak 2765 time0=Paso_timer()-time0;
370 artak 2784 if (verbose) fprintf(stdout,"timing: getRestriction: %e\n",time0);
371 artak 2765
372 artak 2802
373     /*sprintf(filename,"R_%d",level);
374 artak 2760 Paso_SparseMatrix_saveMM(out->R,filename);
375     */
376    
377 gross 2551 }
378 artak 2686 if ( Paso_noError()) {
379 artak 2765
380     time0=Paso_timer();
381 artak 2784
382     Atemp=Paso_SparseMatrix_MatrixMatrix(A_p,out->P);
383     A_c=Paso_SparseMatrix_MatrixMatrix(out->R,Atemp);
384    
385     Paso_SparseMatrix_free(Atemp);
386    
387     /*A_c=Paso_Solver_getCoarseMatrix(A_p,out->R,out->P);*/
388 artak 2765 time0=Paso_timer()-time0;
389 artak 2784 if (verbose) fprintf(stdout,"timing: getCoarseMatrix: %e\n",time0);
390 artak 2765
391 artak 2784
392 artak 2760 /*Paso_Solver_getCoarseMatrix(A_c, A_p,out->R,out->P);*/
393 artak 2767
394 artak 2784
395     /*sprintf(filename,"A_C_%d",level);
396 artak 2760 Paso_SparseMatrix_saveMM(A_c,filename);
397 artak 2767 */
398    
399 artak 2760 out->AMG_of_Coarse=Paso_Solver_getAMG(A_c,level-1,options);
400 gross 2551 }
401 artak 2760
402 artak 2686 /* allocate work arrays for AMG application */
403     if (Paso_noError()) {
404 artak 2767 /*
405     out->x_F=MEMALLOC(n_block*out->n_F,double);
406 artak 2686 out->b_F=MEMALLOC(n_block*out->n_F,double);
407 artak 2767 */
408 artak 2686 out->x_C=MEMALLOC(n_block*out->n_C,double);
409     out->b_C=MEMALLOC(n_block*out->n_C,double);
410    
411 artak 2767 /*if (! (Paso_checkPtr(out->x_F) || Paso_checkPtr(out->b_F) || Paso_checkPtr(out->x_C) || Paso_checkPtr(out->b_C) ) ) {*/
412     if ( ! ( Paso_checkPtr(out->x_C) || Paso_checkPtr(out->b_C) ) ) {
413    
414     /*
415     #pragma omp parallel for private(i) schedule(static)
416 artak 2686 for (i = 0; i < out->n_F; ++i) {
417     out->x_F[i]=0.;
418     out->b_F[i]=0.;
419     }
420 artak 2767 */
421    
422 artak 2686 #pragma omp parallel for private(i) schedule(static)
423     for (i = 0; i < out->n_C; ++i) {
424     out->x_C[i]=0.;
425     out->b_C[i]=0.;
426     }
427     }
428     }
429 artak 2760 Paso_SparseMatrix_free(A_c);
430 artak 2686 }
431 jfenwick 1851 }
432     }
433     TMPMEMFREE(mis_marker);
434     TMPMEMFREE(counter);
435 artak 2686
436 jfenwick 1851 if (Paso_noError()) {
437 artak 2524 if (verbose && level>0 && !out->coarsest_level) {
438 gross 2551 printf("AMG: level: %d: %d unknowns eliminated. %d left.\n",level, out->n_F,out->n_C);
439 jfenwick 1851 }
440     return out;
441     } else {
442     Paso_Solver_AMG_free(out);
443     return NULL;
444     }
445     }
446    
447     /**************************************************************/
448    
449     /* apply AMG precondition b-> x
450    
451     in fact it solves
452    
453 artak 2381 [ I 0 ] [ A_FF 0 ] [ I invA_FF*A_FC ] [ x_F ] = [b_F]
454 jfenwick 1851 [ A_CF*invA_FF I ] [ 0 S ] [ 0 I ] [ x_C ] = [b_C]
455    
456     in the form
457    
458     b->[b_F,b_C]
459     x_F=invA_FF*b_F
460     b_C=b_C-A_CF*x_F
461     x_C=AMG(b_C)
462     b_F=b_F-A_FC*x_C
463     x_F=invA_FF*b_F
464     x<-[x_F,x_C]
465    
466     should be called within a parallel region
467     barrier synconization should be performed to make sure that the input vector available
468    
469     */
470    
471     void Paso_Solver_solveAMG(Paso_Solver_AMG * amg, double * x, double * b) {
472 artak 2107 dim_t i;
473 artak 2507 double time0=0;
474 gross 2551 double *r=NULL, *x0=NULL;
475 artak 2509 bool_t verbose=0;
476 artak 2784
477 artak 2803 dim_t post_sweeps=amg->post_sweeps;
478     dim_t pre_sweeps=amg->pre_sweeps;
479    
480 artak 2699 #ifdef UMFPACK
481     Paso_UMFPACK_Handler * ptr=NULL;
482 artak 2507 #endif
483 artak 2760
484 artak 2784
485 gross 2551 r=MEMALLOC(amg->n,double);
486     x0=MEMALLOC(amg->n,double);
487 artak 2507
488 artak 2524 if (amg->coarsest_level) {
489 artak 2507
490     time0=Paso_timer();
491 artak 2699 /*If all unknown are eliminated then Jacobi is the best preconditioner*/
492 artak 2784 /*Paso_Solver_solveJacobi(amg->GS,x,b);*/
493    
494 artak 2726 if (amg->n_F==0 || amg->n_F==amg->n) {
495 artak 2699 Paso_Solver_solveJacobi(amg->GS,x,b);
496     }
497     else {
498 artak 2712 #ifdef MKL
499     Paso_MKL1(amg->AOffset1,x,b,verbose);
500     #else
501     #ifdef UMFPACK
502 gross 2551 ptr=(Paso_UMFPACK_Handler *)(amg->solver);
503 artak 2652 Paso_UMFPACK1(&ptr,amg->A,x,b,verbose);
504 gross 2551 amg->solver=(void*) ptr;
505 artak 2712 #else
506     Paso_Solver_solveJacobi(amg->GS,x,b);
507 artak 2699 #endif
508 artak 2507 #endif
509 artak 2699 }
510 artak 2784
511 artak 2475 time0=Paso_timer()-time0;
512 artak 2784 if (verbose) fprintf(stdout,"timing: DIRECT SOLVER: %e\n",time0);
513 artak 2507
514 jfenwick 1851 } else {
515 artak 1902 /* presmoothing */
516 artak 2507 time0=Paso_timer();
517 artak 2112 Paso_Solver_solveJacobi(amg->GS,x,b);
518 artak 2803
519     /***********/
520 artak 2816 if (pre_sweeps>1) {
521     #pragma omp parallel for private(i) schedule(static)
522     for (i=0;i<amg->n;++i) r[i]=b[i];
523     }
524 artak 2803
525     while(pre_sweeps>1) {
526     #pragma omp parallel for private(i) schedule(static)
527     for (i=0;i<amg->n;++i) r[i]+=b[i];
528    
529 artak 2816 /* Compute the residual r=r-Ax*/
530 artak 2803 Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
531     /* Go round again*/
532     Paso_Solver_solveJacobi(amg->GS,x,r);
533     pre_sweeps-=1;
534     }
535     /***********/
536    
537 artak 2507 time0=Paso_timer()-time0;
538 artak 2784 if (verbose) fprintf(stdout,"timing: Presmooting: %e\n",time0);
539 artak 2803 /* end of presmoothing */
540 artak 1939
541 artak 2507 time0=Paso_timer();
542 artak 1890 #pragma omp parallel for private(i) schedule(static)
543     for (i=0;i<amg->n;++i) r[i]=b[i];
544    
545     /*r=b-Ax*/
546     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
547 artak 2760
548     /* b_c <- R*r */
549     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(1.,amg->R,r,0.,amg->b_C);
550 artak 1954
551 artak 2507 time0=Paso_timer()-time0;
552 artak 2784 if (verbose) fprintf(stdout,"timing: Before next level: %e\n",time0);
553 artak 2507
554 jfenwick 1851 /* x_C=AMG(b_C) */
555 artak 2760 Paso_Solver_solveAMG(amg->AMG_of_Coarse,amg->x_C,amg->b_C);
556 artak 1890
557 artak 2507 time0=Paso_timer();
558 artak 2726
559 artak 2760 /* x_0 <- P*x_c */
560     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(1.,amg->P,amg->x_C,0.,x0);
561    
562     /* x=x+x0 */
563 artak 1954 #pragma omp parallel for private(i) schedule(static)
564 artak 2760 for (i=0;i<amg->n;++i) x[i]+=x0[i];
565 artak 1954
566 artak 2767 /*postsmoothing*/
567 artak 2803
568 artak 2767 time0=Paso_timer();
569     #pragma omp parallel for private(i) schedule(static)
570     for (i=0;i<amg->n;++i) r[i]=b[i];
571    
572     /*r=b-Ax */
573     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
574     Paso_Solver_solveJacobi(amg->GS,x0,r);
575    
576    
577     #pragma omp parallel for private(i) schedule(static)
578     for (i=0;i<amg->n;++i) {
579     x[i]+=x0[i];
580     }
581 artak 2803 /***************/
582     while(post_sweeps>1) {
583    
584     #pragma omp parallel for private(i) schedule(static)
585     for (i=0;i<amg->n;++i) r[i]=b[i];
586    
587     Paso_SparseMatrix_MatrixVector_CSR_OFFSET0(-1.,amg->A,x,1.,r);
588     Paso_Solver_solveJacobi(amg->GS,x0,r);
589     #pragma omp parallel for private(i) schedule(static)
590     for (i=0;i<amg->n;++i) {
591     x[i]+=x0[i];
592     }
593     post_sweeps-=1;
594     }
595     /**************/
596 artak 2767
597     time0=Paso_timer()-time0;
598 artak 2784 if (verbose) fprintf(stdout,"timing: Postsmoothing: %e\n",time0);
599 artak 2767
600     /*end of postsmoothing*/
601 artak 2107
602 artak 2760 }
603 artak 1890 MEMFREE(r);
604 artak 1954 MEMFREE(x0);
605 artak 2760
606 gross 2551 return;
607 jfenwick 1851 }

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