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

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Revision 1798 - (show annotations)
Wed Sep 17 06:21:12 2008 UTC (10 years, 7 months ago) by gross
File MIME type: text/plain
File size: 13037 byte(s)
Fixes for the JacobeanFreeNewton scheme. Still needs to be tested under OPENMP but runs under MPI.


1
2 /* $Id$ */
3
4 /*******************************************************
5 *
6 * Copyright 2003-2007 by ACceSS MNRF
7 * Copyright 2007 by University of Queensland
8 *
9 * http://esscc.uq.edu.au
10 * Primary Business: Queensland, Australia
11 * Licensed under the Open Software License version 3.0
12 * http://www.opensource.org/licenses/osl-3.0.php
13 *
14 *******************************************************/
15
16 /**************************************************************/
17
18 /* Paso: SystemMatrix: controls iterative linear system solvers */
19
20 /**************************************************************/
21
22 /* Copyrights by ACcESS Australia 2003/04 */
23 /* Author: gross@access.edu.au */
24
25 /**************************************************************/
26
27 #include "Paso.h"
28 #include "SystemMatrix.h"
29 #include "Solver.h"
30 #include "escript/blocktimer.h"
31
32 /***********************************************************************************/
33
34 /* free space */
35
36 void Paso_Solver_free(Paso_SystemMatrix* A) {
37 Paso_Preconditioner_free(A->solver);
38 A->solver=NULL;
39 }
40 /* call the iterative solver: */
41
42 void Paso_Solver(Paso_SystemMatrix* A,double* x,double* b,
43 Paso_Options* options,Paso_Performance* pp) {
44
45 double norm2_of_b,tol,tolerance,time_iter;
46 double *r=NULL,norm2_of_residual,last_norm2_of_residual,norm_max_of_b;
47 double norm2_of_b_local,norm_max_of_b_local,norm2_of_residual_local;
48 double norm_max_of_residual_local,norm_max_of_residual;
49 double last_norm_max_of_residual,*scaling;
50 #ifdef PASO_MPI
51 double loc_norm;
52 #endif
53 dim_t i,totIter,cntIter,method;
54 bool_t finalizeIteration;
55 err_t errorCode;
56 dim_t numSol = Paso_SystemMatrix_getTotalNumCols(A);
57 dim_t numEqua = Paso_SystemMatrix_getTotalNumRows(A);
58 double blocktimer_precond, blocktimer_start = blocktimer_time();
59
60 tolerance=MAX(options->tolerance,EPSILON);
61 Paso_resetError();
62 method=Paso_Options_getSolver(options->method,PASO_PASO,options->symmetric);
63 /* check matrix type */
64 if ((A->type & MATRIX_FORMAT_CSC) || (A->type & MATRIX_FORMAT_OFFSET1) || (A->type & MATRIX_FORMAT_SYM) ) {
65 Paso_setError(TYPE_ERROR,"Iterative solver requires CSR format with unsymmetric storage scheme and index offset 0.");
66 }
67 if (A->col_block_size != A->row_block_size) {
68 Paso_setError(TYPE_ERROR,"Iterative solver requires row and column block sizes to be equal.");
69 }
70 if (Paso_SystemMatrix_getGlobalNumCols(A) != Paso_SystemMatrix_getGlobalNumRows(A)) {
71 Paso_setError(TYPE_ERROR,"Iterative solver requires a square matrix.");
72 return;
73 }
74 /* this for testing only */
75 if (method==PASO_NONLINEAR_GMRES) {
76 Paso_Function* F=NULL;
77 F=Paso_Function_LinearSystem_alloc(A,b,options);
78 Paso_Solver_solvePreconditioner(A,x,b);
79 errorCode=Paso_Solver_NewtonGMRES(F,x,options,pp);
80 if (errorCode!=NO_ERROR) {
81 Paso_setError(SYSTEM_ERROR,"Paso_Solver_NewtonGMRES: an error has occured.");
82 }
83 Paso_Function_LinearSystem_free(F);
84 return;
85 }
86 /* ========================= */
87 Performance_startMonitor(pp,PERFORMANCE_ALL);
88 if (Paso_noError()) {
89 /* get normalization */
90 scaling=Paso_SystemMatrix_borrowNormalization(A);
91 if (Paso_noError()) {
92 /* get the norm of the right hand side */
93 norm2_of_b=0.;
94 norm_max_of_b=0.;
95 #pragma omp parallel private(norm2_of_b_local,norm_max_of_b_local)
96 {
97 norm2_of_b_local=0.;
98 norm_max_of_b_local=0.;
99 #pragma omp for private(i) schedule(static)
100 for (i = 0; i < numEqua ; ++i) {
101 norm2_of_b_local += b[i] * b[i];
102 norm_max_of_b_local = MAX(ABS(scaling[i]*b[i]),norm_max_of_b_local);
103 }
104 #pragma omp critical
105 {
106 norm2_of_b += norm2_of_b_local;
107 norm_max_of_b = MAX(norm_max_of_b_local,norm_max_of_b);
108 }
109 }
110 /* TODO: use one call */
111 #ifdef PASO_MPI
112 {
113 loc_norm = norm2_of_b;
114 MPI_Allreduce(&loc_norm,&norm2_of_b, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
115 loc_norm = norm_max_of_b;
116 MPI_Allreduce(&loc_norm,&norm_max_of_b, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
117 }
118 #endif
119 norm2_of_b=sqrt(norm2_of_b);
120
121 /* if norm2_of_b==0 we are ready: x=0 */
122 if (norm2_of_b <=0.) {
123 #pragma omp parallel for private(i) schedule(static)
124 for (i = 0; i < numSol; i++) x[i]=0.;
125 if (options->verbose) printf("right hand side is identical zero.\n");
126 } else {
127 if (options->verbose) {
128 printf("l2/lmax-norm of right hand side is %e/%e.\n",norm2_of_b,norm_max_of_b);
129 printf("l2/lmax-stopping criterion is %e/%e.\n",norm2_of_b*tolerance,norm_max_of_b*tolerance);
130 switch (method) {
131 case PASO_BICGSTAB:
132 printf("Iterative method is BiCGStab.\n");
133 break;
134 case PASO_PCG:
135 printf("Iterative method is PCG.\n");
136 break;
137 case PASO_TFQMR:
138 printf("Iterative method is TFQMR.\n");
139 break;
140 case PASO_MINRES:
141 printf("Iterative method is MINRES.\n");
142 break;
143 case PASO_PRES20:
144 printf("Iterative method is PRES20.\n");
145 break;
146 case PASO_GMRES:
147 if (options->restart>0) {
148 printf("Iterative method is GMRES(%d,%d)\n",options->truncation,options->restart);
149 } else {
150 printf("Iterative method is GMRES(%d)\n",options->truncation);
151 }
152 break;
153 }
154 }
155 /* construct the preconditioner */
156
157 blocktimer_precond = blocktimer_time();
158 Performance_startMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
159 Paso_Solver_setPreconditioner(A,options);
160 Performance_stopMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
161 blocktimer_increment("Paso_Solver_setPreconditioner()", blocktimer_precond);
162 if (! Paso_noError()) return;
163 time_iter=Paso_timer();
164 /* get an initial guess by evaluating the preconditioner */
165 Paso_Solver_solvePreconditioner(A,x,b);
166 /* start the iteration process :*/
167 r=TMPMEMALLOC(numEqua,double);
168 Paso_checkPtr(r);
169 if (Paso_noError()) {
170 totIter = 0;
171 finalizeIteration = FALSE;
172 last_norm2_of_residual=norm2_of_b;
173 last_norm_max_of_residual=norm_max_of_b;
174 /* Loop */
175 while (! finalizeIteration) {
176 cntIter = options->iter_max - totIter;
177 finalizeIteration = TRUE;
178 /* Set initial residual. */
179 norm2_of_residual = 0;
180 norm_max_of_residual = 0;
181 #pragma omp parallel for private(i) schedule(static)
182 for (i = 0; i < numEqua; i++) r[i]=b[i];
183 Paso_SystemMatrix_MatrixVector_CSR_OFFSET0(DBLE(-1), A, x, DBLE(1), r);
184
185 #pragma omp parallel private(norm2_of_residual_local,norm_max_of_residual_local)
186 {
187 norm2_of_residual_local = 0;
188 norm_max_of_residual_local = 0;
189 #pragma omp for private(i) schedule(static)
190 for (i = 0; i < numEqua; i++) {
191 norm2_of_residual_local+= r[i] * r[i];
192 norm_max_of_residual_local=MAX(ABS(scaling[i]*r[i]),norm_max_of_residual_local);
193 }
194 #pragma omp critical
195 {
196 norm2_of_residual += norm2_of_residual_local;
197 norm_max_of_residual = MAX(norm_max_of_residual_local,norm_max_of_residual);
198 }
199 }
200 /* TODO: use one call */
201 #ifdef PASO_MPI
202 loc_norm = norm2_of_residual;
203 MPI_Allreduce(&loc_norm,&norm2_of_residual, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
204 loc_norm = norm_max_of_residual;
205 MPI_Allreduce(&loc_norm,&norm_max_of_residual, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
206 #endif
207 norm2_of_residual =sqrt(norm2_of_residual);
208
209 if (options->verbose) printf("Step %5d: l2/lmax-norm of residual is %e/%e",totIter,norm2_of_residual,norm_max_of_residual);
210 if (totIter>0 && norm2_of_residual>=last_norm2_of_residual && norm_max_of_residual>=last_norm_max_of_residual) {
211 if (options->verbose) printf(" divergence!\n");
212 Paso_setError(WARNING, "No improvement during iteration. Iterative solver gives up.");
213 } else {
214 /* */
215 if (norm2_of_residual>tolerance*norm2_of_b || norm_max_of_residual>tolerance*norm_max_of_b ) {
216 tol=tolerance*MIN(norm2_of_b,0.1*norm2_of_residual/norm_max_of_residual*norm_max_of_b);
217 if (options->verbose) printf(" (new tolerance = %e).\n",tol);
218 last_norm2_of_residual=norm2_of_residual;
219 last_norm_max_of_residual=norm_max_of_residual;
220 /* call the solver */
221 switch (method) {
222 case PASO_BICGSTAB:
223 errorCode = Paso_Solver_BiCGStab(A, r, x, &cntIter, &tol, pp);
224 break;
225 case PASO_PCG:
226 errorCode = Paso_Solver_PCG(A, r, x, &cntIter, &tol, pp);
227 break;
228 case PASO_TFQMR:
229 errorCode = Paso_Solver_TFQMR(A, r, x, &cntIter, &tol, pp);
230 break;
231 case PASO_MINRES:
232 errorCode = Paso_Solver_MINRES(A, r, x, &cntIter, &tolerance, &tol, pp);
233 break;
234 case PASO_PRES20:
235 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,5,20, pp);
236 break;
237 case PASO_GMRES:
238 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,options->truncation,options->restart, pp);
239 break;
240 }
241 totIter += cntIter;
242 /* error handling */
243 if (errorCode==NO_ERROR) {
244 finalizeIteration = FALSE;
245 } else if (errorCode==SOLVER_MAXITER_REACHED) {
246 Paso_setError(WARNING,"maximum number of iteration step reached.\nReturned solution does not fulfil stopping criterion.");
247 if (options->verbose) printf("Maximum number of iterations reached.!\n");
248 } else if (errorCode == SOLVER_INPUT_ERROR ) {
249 Paso_setError(SYSTEM_ERROR,"illegal dimension in iterative solver.");
250 if (options->verbose) printf("Internal error!\n");
251 } else if ( errorCode == SOLVER_BREAKDOWN ) {
252 if (cntIter <= 1) {
253 Paso_setError(ZERO_DIVISION_ERROR, "fatal break down in iterative solver.");
254 if (options->verbose) printf("Uncurable break down!\n");
255 } else {
256 if (options->verbose) printf("Breakdown at iter %d (residual = %e). Restarting ...\n", cntIter+totIter, tol);
257 finalizeIteration = FALSE;
258 }
259 } else {
260 if (options->verbose) printf(". convergence! \n");
261 }
262 }
263 } /* while */
264 }
265 MEMFREE(r);
266 time_iter=Paso_timer()-time_iter;
267 if (options->verbose) {
268 printf("\ntiming: solver: %.4e sec\n",time_iter);
269 if (totIter>0) printf("timing: per iteration step: %.4e sec\n",time_iter/totIter);
270 }
271 }
272 }
273 }
274 }
275 Performance_stopMonitor(pp,PERFORMANCE_ALL);
276 blocktimer_increment("Paso_Solver()", blocktimer_start);
277 }

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