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

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Revision 2358 - (show annotations)
Wed Apr 1 22:25:24 2009 UTC (10 years ago) by gross
File MIME type: text/plain
File size: 13926 byte(s)
mpi is not really ready yet.
1 /*******************************************************
2 *
3 * Copyright (c) 2003-2008 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: gross@access.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_Preconditioner_free(A->solver);
36 A->solver=NULL;
37 }
38 /* call the iterative solver: */
39
40 void Paso_Solver(Paso_SystemMatrix* A,double* x,double* b,
41 Paso_Options* options,Paso_Performance* pp) {
42
43 double norm2_of_b,tol,tolerance,time_iter;
44 double *r=NULL,norm2_of_residual,last_norm2_of_residual,norm_max_of_b;
45 double norm2_of_b_local,norm_max_of_b_local,norm2_of_residual_local;
46 double norm_max_of_residual_local,norm_max_of_residual;
47 double last_norm_max_of_residual,*scaling;
48 #ifdef PASO_MPI
49 double loc_norm;
50 #endif
51 dim_t i,totIter,cntIter,method;
52 bool_t finalizeIteration;
53 err_t errorCode=NO_ERROR;
54 dim_t numSol = Paso_SystemMatrix_getTotalNumCols(A);
55 dim_t numEqua = Paso_SystemMatrix_getTotalNumRows(A);
56 double blocktimer_precond, blocktimer_start = blocktimer_time();
57
58 Paso_resetError();
59 tolerance=options->tolerance;
60 if (tolerance < 100.* EPSILON) {
61 Paso_setError(VALUE_ERROR,"Paso_Solver: Tolerance is too small.");
62 }
63 if (tolerance >1.) {
64 Paso_setError(VALUE_ERROR,"Paso_Solver: Tolerance mut be less than one.");
65 }
66 method=Paso_Options_getSolver(options->method,PASO_PASO,options->symmetric,A->mpi_info);
67 /* check matrix type */
68 if ((A->type & MATRIX_FORMAT_CSC) || (A->type & MATRIX_FORMAT_OFFSET1) || (A->type & MATRIX_FORMAT_SYM) ) {
69 Paso_setError(TYPE_ERROR,"Paso_Solver: Iterative solver requires CSR format with unsymmetric storage scheme and index offset 0.");
70 }
71 if (A->col_block_size != A->row_block_size) {
72 Paso_setError(TYPE_ERROR,"Paso_Solver: Iterative solver requires row and column block sizes to be equal.");
73 }
74 if (Paso_SystemMatrix_getGlobalNumCols(A) != Paso_SystemMatrix_getGlobalNumRows(A)) {
75 Paso_setError(TYPE_ERROR,"Paso_Solver: Iterative solver requires a square matrix.");
76 return;
77 }
78 /* this for testing only */
79 if (method==PASO_NONLINEAR_GMRES) {
80 Paso_Function* F=NULL;
81 F=Paso_Function_LinearSystem_alloc(A,b,options);
82 Paso_Solver_solvePreconditioner(A,x,b);
83 errorCode=Paso_Solver_NewtonGMRES(F,x,options,pp);
84 if (errorCode!=NO_ERROR) {
85 Paso_setError(SYSTEM_ERROR,"Paso_Solver_NewtonGMRES: an error has occured.");
86 }
87 Paso_Function_LinearSystem_free(F);
88 return;
89 }
90 /* ========================= */
91 Performance_startMonitor(pp,PERFORMANCE_ALL);
92 if (Paso_noError()) {
93 /* get normalization */
94 scaling=Paso_SystemMatrix_borrowNormalization(A);
95 if (Paso_noError()) {
96 /* get the norm of the right hand side */
97 norm2_of_b=0.;
98 norm_max_of_b=0.;
99 #pragma omp parallel private(norm2_of_b_local,norm_max_of_b_local)
100 {
101 norm2_of_b_local=0.;
102 norm_max_of_b_local=0.;
103 #pragma omp for private(i) schedule(static)
104 for (i = 0; i < numEqua ; ++i) {
105 norm2_of_b_local += b[i] * b[i];
106 norm_max_of_b_local = MAX(ABS(scaling[i]*b[i]),norm_max_of_b_local);
107 }
108 #pragma omp critical
109 {
110 norm2_of_b += norm2_of_b_local;
111 norm_max_of_b = MAX(norm_max_of_b_local,norm_max_of_b);
112 }
113 }
114 /* TODO: use one call */
115 #ifdef PASO_MPI
116 {
117 loc_norm = norm2_of_b;
118 MPI_Allreduce(&loc_norm,&norm2_of_b, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
119 loc_norm = norm_max_of_b;
120 MPI_Allreduce(&loc_norm,&norm_max_of_b, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
121 }
122 #endif
123 norm2_of_b=sqrt(norm2_of_b);
124
125 /* if norm2_of_b==0 we are ready: x=0 */
126 if (norm2_of_b <=0.) {
127 #pragma omp parallel for private(i) schedule(static)
128 for (i = 0; i < numSol; i++) x[i]=0.;
129 if (options->verbose) printf("right hand side is identical zero.\n");
130 } else {
131 if (options->verbose) {
132 printf("Paso_Solver: l2/lmax-norm of right hand side is %e/%e.\n",norm2_of_b,norm_max_of_b);
133 printf("Paso_Solver: l2/lmax-stopping criterion is %e/%e.\n",norm2_of_b*tolerance,norm_max_of_b*tolerance);
134 switch (method) {
135 case PASO_BICGSTAB:
136 printf("Paso_Solver: Iterative method is BiCGStab.\n");
137 break;
138 case PASO_PCG:
139 printf("Paso_Solver: Iterative method is PCG.\n");
140 break;
141 case PASO_TFQMR:
142 printf("Paso_Solver: Iterative method is TFQMR.\n");
143 break;
144 case PASO_MINRES:
145 printf("Paso_Solver: Iterative method is MINRES.\n");
146 break;
147 case PASO_PRES20:
148 printf("Paso_Solver: Iterative method is PRES20.\n");
149 break;
150 case PASO_GMRES:
151 if (options->restart>0) {
152 printf("Paso_Solver: Iterative method is GMRES(%d,%d)\n",options->truncation,options->restart);
153 } else {
154 printf("Paso_Solver: Iterative method is GMRES(%d)\n",options->truncation);
155 }
156 break;
157 }
158 }
159 /* construct the preconditioner */
160 blocktimer_precond = blocktimer_time();
161 Performance_startMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
162 Paso_Solver_setPreconditioner(A,options);
163 Performance_stopMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
164 blocktimer_increment("Paso_Solver_setPreconditioner()", blocktimer_precond);
165 if (! Paso_noError()) return;
166 time_iter=Paso_timer();
167 /* get an initial guess by evaluating the preconditioner */
168 Paso_Solver_solvePreconditioner(A,x,b);
169 /* start the iteration process :*/
170 r=TMPMEMALLOC(numEqua,double);
171 Paso_checkPtr(r);
172 if (Paso_noError()) {
173 totIter = 1;
174 finalizeIteration = FALSE;
175 last_norm2_of_residual=norm2_of_b;
176 last_norm_max_of_residual=norm_max_of_b;
177 /* Loop */
178 while (! finalizeIteration) {
179 cntIter = options->iter_max - totIter;
180 finalizeIteration = TRUE;
181 /* Set initial residual. */
182 norm2_of_residual = 0;
183 norm_max_of_residual = 0;
184 #pragma omp parallel for private(i) schedule(static)
185 for (i = 0; i < numEqua; i++) r[i]=b[i];
186 Paso_SystemMatrix_MatrixVector_CSR_OFFSET0(DBLE(-1), A, x, DBLE(1), r);
187 #pragma omp parallel private(norm2_of_residual_local,norm_max_of_residual_local)
188 {
189 norm2_of_residual_local = 0;
190 norm_max_of_residual_local = 0;
191 #pragma omp for private(i) schedule(static)
192 for (i = 0; i < numEqua; i++) {
193 norm2_of_residual_local+= r[i] * r[i];
194 norm_max_of_residual_local=MAX(ABS(scaling[i]*r[i]),norm_max_of_residual_local);
195 }
196 #pragma omp critical
197 {
198 norm2_of_residual += norm2_of_residual_local;
199 norm_max_of_residual = MAX(norm_max_of_residual_local,norm_max_of_residual);
200 }
201 }
202 /* TODO: use one call */
203 #ifdef PASO_MPI
204 loc_norm = norm2_of_residual;
205 MPI_Allreduce(&loc_norm,&norm2_of_residual, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
206 loc_norm = norm_max_of_residual;
207 MPI_Allreduce(&loc_norm,&norm_max_of_residual, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
208 #endif
209 norm2_of_residual =sqrt(norm2_of_residual);
210
211 if (options->verbose) printf("Paso_Solver: Step %5d: l2/lmax-norm of residual is %e/%e",totIter,norm2_of_residual,norm_max_of_residual);
212 if (totIter>1 && norm2_of_residual>=last_norm2_of_residual && norm_max_of_residual>=last_norm_max_of_residual) {
213 if (options->verbose) printf(" divergence!\n");
214 Paso_setError(WARNING, "Paso_Solver: No improvement during iteration. Iterative solver gives up.");
215 } else {
216 /* */
217 if (norm2_of_residual>tolerance*norm2_of_b || norm_max_of_residual>tolerance*norm_max_of_b ) {
218 tol=tolerance*MIN(norm2_of_b,0.1*norm2_of_residual/norm_max_of_residual*norm_max_of_b);
219 if (options->verbose) printf(" (new tolerance = %e).\n",tol);
220 last_norm2_of_residual=norm2_of_residual;
221 last_norm_max_of_residual=norm_max_of_residual;
222 /* call the solver */
223 switch (method) {
224 case PASO_BICGSTAB:
225 errorCode = Paso_Solver_BiCGStab(A, r, x, &cntIter, &tol, pp);
226 break;
227 case PASO_PCG:
228 errorCode = Paso_Solver_PCG(A, r, x, &cntIter, &tol, pp);
229 break;
230 case PASO_TFQMR:
231 errorCode = Paso_Solver_TFQMR(A, r, x, &cntIter, &tol, pp);
232 break;
233 case PASO_MINRES:
234 errorCode = Paso_Solver_MINRES(A, r, x, &cntIter, &tol, pp);
235 break;
236 case PASO_PRES20:
237 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,5,20, pp);
238 break;
239 case PASO_GMRES:
240 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,options->truncation,options->restart, pp);
241 break;
242 }
243 totIter += cntIter;
244 /* error handling */
245 if (errorCode==NO_ERROR) {
246 finalizeIteration = FALSE;
247 } else if (errorCode==SOLVER_MAXITER_REACHED) {
248 Paso_setError(WARNING,"Paso_Solver: maximum number of iteration step reached.\nReturned solution does not fulfil stopping criterion.");
249 if (options->verbose) printf("Paso_Solver: Maximum number of iterations reached.!\n");
250 } else if (errorCode == SOLVER_INPUT_ERROR ) {
251 Paso_setError(SYSTEM_ERROR,"Paso_Solver: illegal dimension in iterative solver.");
252 if (options->verbose) printf("Paso_Solver: Internal error!\n");
253 } else if ( errorCode == SOLVER_BREAKDOWN ) {
254 if (cntIter <= 1) {
255 Paso_setError(ZERO_DIVISION_ERROR, "Paso_Solver: fatal break down in iterative solver.");
256 if (options->verbose) printf("Paso_Solver: Uncurable break down!\n");
257 } else {
258 if (options->verbose) printf("Paso_Solver: Breakdown at iter %d (residual = %e). Restarting ...\n", cntIter+totIter, tol);
259 finalizeIteration = FALSE;
260 }
261 } else {
262 if (options->verbose) printf(". convergence! \n");
263 }
264 }
265 } /* while */
266 }
267 MEMFREE(r);
268 time_iter=Paso_timer()-time_iter;
269 if (options->verbose) {
270 printf("\ntiming: Paso_Solver: %.4e sec\n",time_iter);
271 if (totIter>1) {
272 if(totIter==options->iter_max) {
273 printf("timing: Total MAX steps, time per iteration step: %.4e sec\n",time_iter/totIter);
274 } else {
275 printf("timing: Total %d steps, time per iteration step: %.4e sec\n",totIter,time_iter/totIter);
276 }
277 }
278 else {
279 printf("timing: Total 1 step, time per iteration step: %.4e sec\n",time_iter);
280 }
281 }
282 }
283 }
284 }
285 }
286 Performance_stopMonitor(pp,PERFORMANCE_ALL);
287 blocktimer_increment("Paso_Solver()", blocktimer_start);
288 }

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