/[escript]/trunk/paso/src/Solver.c
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Contents of /trunk/paso/src/Solver.c

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Revision 3369 - (show annotations)
Fri Nov 19 06:26:11 2010 UTC (10 years, 3 months ago) by gross
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matrix balance introduced in paso
1 /*******************************************************
2 *
3 * Copyright (c) 2003-2010 by University of Queensland
4 * Earth Systems Science Computational Center (ESSCC)
5 * http://www.uq.edu.au/esscc
6 *
7 * Primary Business: Queensland, Australia
8 * Licensed under the Open Software License version 3.0
9 * http://www.opensource.org/licenses/osl-3.0.php
10 *
11 *******************************************************/
12
13
14 /**************************************************************/
15
16 /* Paso: SystemMatrix: controls iterative linear system solvers */
17
18 /**************************************************************/
19
20 /* Copyrights by ACcESS Australia 2003/04 */
21 /* Author: Lutz Gross, l.gross@uq.edu.au */
22
23 /**************************************************************/
24
25 #include "Paso.h"
26 #include "SystemMatrix.h"
27 #include "Solver.h"
28 #include "esysUtils/blocktimer.h"
29
30 /***********************************************************************************/
31
32 /* free space */
33
34 void Paso_Solver_free(Paso_SystemMatrix* A) {
35 Paso_SystemMatrix_freePreconditioner(A);
36 }
37 /* call the iterative solver: */
38
39 void Paso_Solver(Paso_SystemMatrix* A,double* x,double* b,
40 Paso_Options* options,Paso_Performance* pp) {
41
42 double norm2_of_b,tol,tolerance,time_iter,net_time_start;
43 double *r=NULL,norm2_of_residual,last_norm2_of_residual,norm_max_of_b;
44 double norm2_of_b_local,norm_max_of_b_local,norm2_of_residual_local;
45 double norm_max_of_residual_local,norm_max_of_residual;
46 double last_norm_max_of_residual;
47 #ifdef ESYS_MPI
48 double loc_norm;
49 #endif
50 dim_t i,totIter=0,cntIter,method;
51 bool_t finalizeIteration;
52 err_t errorCode=SOLVER_NO_ERROR;
53 const dim_t numSol = Paso_SystemMatrix_getTotalNumCols(A);
54 const dim_t numEqua = Paso_SystemMatrix_getTotalNumRows(A);
55 double blocktimer_precond, blocktimer_start = blocktimer_time();
56 double *x0=NULL;
57
58
59 Esys_resetError();
60 tolerance=options->tolerance;
61 if (tolerance < 100.* EPSILON) {
62 Esys_setError(VALUE_ERROR,"Paso_Solver: Tolerance is too small.");
63 }
64 if (tolerance >1.) {
65 Esys_setError(VALUE_ERROR,"Paso_Solver: Tolerance mut be less than one.");
66 }
67 method=Paso_Options_getSolver(options->method,PASO_PASO,options->symmetric,A->mpi_info);
68 /* check matrix type */
69 if ((A->type & MATRIX_FORMAT_CSC) || (A->type & MATRIX_FORMAT_OFFSET1) ) {
70 Esys_setError(TYPE_ERROR,"Paso_Solver: Iterative solver requires CSR format with unsymmetric storage scheme and index offset 0.");
71 }
72 if (A->col_block_size != A->row_block_size) {
73 Esys_setError(TYPE_ERROR,"Paso_Solver: Iterative solver requires row and column block sizes to be equal.");
74 }
75 if (Paso_SystemMatrix_getGlobalNumCols(A) != Paso_SystemMatrix_getGlobalNumRows(A)) {
76 Esys_setError(TYPE_ERROR,"Paso_Solver: Iterative solver requires a square matrix.");
77 return;
78 }
79 /*if (A->block_size != 1 && options->preconditioner==PASO_AMG) {
80 Esys_setError(TYPE_ERROR,"Paso_Solver: AMG on systems not supported yet.");
81 }
82 */
83 time_iter=Esys_timer();
84 /* this for testing only */
85 if (method==PASO_NONLINEAR_GMRES) {
86 Paso_Function* F=NULL;
87 F=Paso_Function_LinearSystem_alloc(A,b,options);
88 Paso_SystemMatrix_solvePreconditioner(A,x,b);
89 errorCode=Paso_Solver_NewtonGMRES(F,x,options,pp);
90 if (errorCode!=NO_ERROR) {
91 Esys_setError(SYSTEM_ERROR,"Paso_Solver_NewtonGMRES: an error has occured.");
92 }
93 Paso_Function_LinearSystem_free(F);
94 return;
95 }
96
97 r=TMPMEMALLOC(numEqua,double);
98 x0=TMPMEMALLOC(numEqua,double);
99 Esys_checkPtr(r);
100 Esys_checkPtr(x0);
101 Paso_SystemMatrix_balance(A);
102 options->num_level=0;
103 options->num_inner_iter=0;
104
105 /* ========================= */
106 if (Esys_noError()) {
107 Performance_startMonitor(pp,PERFORMANCE_ALL);
108
109 Paso_SystemMatrix_applyBalance(A, r, b, TRUE);
110 /* get the norm of the right hand side */
111 norm2_of_b=0.;
112 norm_max_of_b=0.;
113 #pragma omp parallel private(norm2_of_b_local,norm_max_of_b_local)
114 {
115 norm2_of_b_local=0.;
116 norm_max_of_b_local=0.;
117 #pragma omp for private(i) schedule(static)
118 for (i = 0; i < numEqua ; ++i) {
119 norm2_of_b_local += r[i] * r[i];
120 norm_max_of_b_local = MAX(ABS(r[i]),norm_max_of_b_local);
121 }
122 #pragma omp critical
123 {
124 norm2_of_b += norm2_of_b_local;
125 norm_max_of_b = MAX(norm_max_of_b_local,norm_max_of_b);
126 }
127 }
128 /* TODO: use one call */
129 #ifdef ESYS_MPI
130 {
131 loc_norm = norm2_of_b;
132 MPI_Allreduce(&loc_norm,&norm2_of_b, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
133 loc_norm = norm_max_of_b;
134 MPI_Allreduce(&loc_norm,&norm_max_of_b, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
135 }
136 #endif
137 norm2_of_b=sqrt(norm2_of_b);
138 /* if norm2_of_b==0 we are ready: x=0 */
139 if ( IS_NAN(norm2_of_b) || IS_NAN(norm_max_of_b) ) {
140 Esys_setError(VALUE_ERROR,"Paso_Solver: Matrix or right hand side contains undefined values.");
141 } else if (norm2_of_b <=0.) {
142
143 #pragma omp parallel for private(i) schedule(static)
144 for (i = 0; i < numSol; i++) x[i]=0.;
145 if (options->verbose) printf("right hand side is identical zero.\n");
146
147 } else {
148
149 if (options->verbose) {
150 printf("Paso_Solver: l2/lmax-norm of right hand side is %e/%e.\n",norm2_of_b,norm_max_of_b);
151 printf("Paso_Solver: l2/lmax-stopping criterion is %e/%e.\n",norm2_of_b*tolerance,norm_max_of_b*tolerance);
152 switch (method) {
153 case PASO_BICGSTAB:
154 printf("Paso_Solver: Iterative method is BiCGStab.\n");
155 break;
156 case PASO_PCG:
157 printf("Paso_Solver: Iterative method is PCG.\n");
158 break;
159 case PASO_TFQMR:
160 printf("Paso_Solver: Iterative method is TFQMR.\n");
161 break;
162 case PASO_MINRES:
163 printf("Paso_Solver: Iterative method is MINRES.\n");
164 break;
165 case PASO_PRES20:
166 printf("Paso_Solver: Iterative method is PRES20.\n");
167 break;
168 case PASO_GMRES:
169 if (options->restart>0) {
170 printf("Paso_Solver: Iterative method is GMRES(%d,%d)\n",options->truncation,options->restart);
171 } else {
172 printf("Paso_Solver: Iterative method is GMRES(%d)\n",options->truncation);
173 }
174 break;
175 }
176
177 }
178
179 /* construct the preconditioner */
180 blocktimer_precond = blocktimer_time();
181 Performance_startMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
182 Paso_SystemMatrix_setPreconditioner(A,options);
183 Performance_stopMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
184 blocktimer_increment("Paso_Solver_setPreconditioner()", blocktimer_precond);
185 options->set_up_time=Esys_timer()-time_iter;
186 if (Esys_noError()) {
187
188
189 /* get an initial guess by evaluating the preconditioner */
190 Paso_SystemMatrix_solvePreconditioner(A,x,r);
191
192 totIter = 1;
193 finalizeIteration = FALSE;
194 last_norm2_of_residual=norm2_of_b;
195 last_norm_max_of_residual=norm_max_of_b;
196 net_time_start=Esys_timer();
197
198 /* Loop */
199 while (! finalizeIteration) {
200 cntIter = options->iter_max - totIter;
201 finalizeIteration = TRUE;
202
203 /* Set initial residual. */
204 if (totIter>1) Paso_SystemMatrix_applyBalance(A, r, b, TRUE); /* in the first iteration r = balance * b already */
205
206 Paso_SystemMatrix_MatrixVector_CSR_OFFSET0(DBLE(-1), A, x, DBLE(1), r);
207
208 norm2_of_residual = 0;
209 norm_max_of_residual = 0;
210 #pragma omp parallel private(norm2_of_residual_local,norm_max_of_residual_local)
211 {
212 norm2_of_residual_local = 0;
213 norm_max_of_residual_local = 0;
214 #pragma omp for private(i) schedule(static)
215 for (i = 0; i < numEqua; i++) {
216 norm2_of_residual_local+= r[i] * r[i];
217 norm_max_of_residual_local=MAX(ABS(r[i]),norm_max_of_residual_local);
218 }
219 #pragma omp critical
220 {
221 norm2_of_residual += norm2_of_residual_local;
222 norm_max_of_residual = MAX(norm_max_of_residual_local,norm_max_of_residual);
223 }
224 }
225 /* TODO: use one call */
226 #ifdef ESYS_MPI
227 loc_norm = norm2_of_residual;
228 MPI_Allreduce(&loc_norm,&norm2_of_residual, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
229 loc_norm = norm_max_of_residual;
230 MPI_Allreduce(&loc_norm,&norm_max_of_residual, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
231 #endif
232 norm2_of_residual =sqrt(norm2_of_residual);
233 options->residual_norm=norm2_of_residual;
234
235 if (options->verbose) printf("Paso_Solver: Step %5d: l2/lmax-norm of residual is %e/%e",totIter,norm2_of_residual,norm_max_of_residual);
236
237 if (totIter>1 && norm2_of_residual>=last_norm2_of_residual && norm_max_of_residual>=last_norm_max_of_residual) {
238
239 if (options->verbose) printf(" divergence!\n");
240 Esys_setError(DIVERGED, "Paso_Solver: No improvement during iteration. Iterative solver gives up.");
241
242 } else {
243 if (norm2_of_residual>tolerance*norm2_of_b || norm_max_of_residual>tolerance*norm_max_of_b ) {
244
245 tol=tolerance*MIN(norm2_of_b,0.1*norm2_of_residual/norm_max_of_residual*norm_max_of_b);
246 if (options->verbose) printf(" (new tolerance = %e).\n",tol);
247
248 last_norm2_of_residual=norm2_of_residual;
249 last_norm_max_of_residual=norm_max_of_residual;
250
251 /* call the solver */
252 switch (method) {
253 case PASO_BICGSTAB:
254 errorCode = Paso_Solver_BiCGStab(A, r, x, &cntIter, &tol, pp);
255 break;
256 case PASO_PCG:
257 errorCode = Paso_Solver_PCG(A, r, x, &cntIter, &tol, pp);
258 break;
259 case PASO_TFQMR:
260 tol=tolerance*norm2_of_residual/norm2_of_b;
261 errorCode = Paso_Solver_TFQMR(A, r, x0, &cntIter, &tol, pp);
262 #pragma omp for private(i) schedule(static)
263 for (i = 0; i < numEqua; i++) {
264 x[i]+= x0[i];
265 }
266 break;
267 case PASO_MINRES:
268 /* tol=tolerance*norm2_of_residual/norm2_of_b; */
269 errorCode = Paso_Solver_MINRES(A, r, x, &cntIter, &tol, pp);
270 break;
271 case PASO_PRES20:
272 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,5,20, pp);
273 break;
274 case PASO_GMRES:
275 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,options->truncation,options->restart, pp);
276 break;
277 }
278
279 totIter += cntIter;
280
281 /* error handling */
282 if (errorCode==SOLVER_NO_ERROR) {
283 finalizeIteration = FALSE;
284 } else if (errorCode==SOLVER_MAXITER_REACHED) {
285 Esys_setError(DIVERGED,"Paso_Solver: maximum number of iteration step reached.\nReturned solution does not fulfil stopping criterion.");
286 if (options->verbose) printf("Paso_Solver: Maximum number of iterations reached.!\n");
287 } else if (errorCode == SOLVER_INPUT_ERROR ) {
288 Esys_setError(SYSTEM_ERROR,"Paso_Solver: illegal dimension in iterative solver.");
289 if (options->verbose) printf("Paso_Solver: Internal error!\n");
290 } else if (errorCode == SOLVER_NEGATIVE_NORM_ERROR) {
291 Esys_setError(VALUE_ERROR,"Paso_Solver: negative energy norm (try other solver or preconditioner).");
292 if (options->verbose) printf("Paso_Solver: negative energy norm (try other solver or preconditioner)!\n");
293 } else if ( errorCode == SOLVER_BREAKDOWN ) {
294 if (cntIter <= 1) {
295 Esys_setError(ZERO_DIVISION_ERROR, "Paso_Solver: fatal break down in iterative solver.");
296 if (options->verbose) printf("Paso_Solver: Uncurable break down!\n");
297 } else {
298 if (options->verbose) printf("Paso_Solver: Breakdown at iter %d (residual = %e). Restarting ...\n", totIter, tol);
299 finalizeIteration = FALSE;
300 }
301 } else {
302 Esys_setError(SYSTEM_ERROR,"Paso_Solver:generic error in solver.");
303 if (options->verbose) printf("Paso_Solver: generic error in solver!\n");
304 }
305 } else {
306 if (options->verbose) printf(". convergence! \n");
307 options->converged=TRUE;
308 }
309 }
310 } /* while */
311 options->net_time=Esys_timer()-net_time_start;
312 }
313 options->num_iter=totIter;
314 Paso_SystemMatrix_applyBalanceInPlace(A, x, FALSE);
315 }
316
317 }
318 MEMFREE(r);
319 MEMFREE(x0);
320 options->time=Esys_timer()-time_iter;
321 Performance_stopMonitor(pp,PERFORMANCE_ALL);
322 blocktimer_increment("Paso_Solver()", blocktimer_start);
323 }

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