/[escript]/trunk-mpi-branch/paso/src/Solver.c
ViewVC logotype

Contents of /trunk-mpi-branch/paso/src/Solver.c

Parent Directory Parent Directory | Revision Log Revision Log


Revision 1196 - (show annotations)
Fri Jun 15 03:45:48 2007 UTC (11 years, 10 months ago) by ksteube
File MIME type: text/plain
File size: 13459 byte(s)
Use of PAPI on solver is now enabled with papi_instrument_solver=1 in scons/ess_options.py.
Can instrument other blocks of code with blockpapi.c.
Added interval timers to grad, integrate and Assemble_PDE.

1 /* $Id$ */
2
3
4 /*
5 ********************************************************************************
6 * Copyright 2006 by ACcESS MNRF *
7 * *
8 * http://www.access.edu.au *
9 * Primary Business: Queensland, Australia *
10 * Licensed under the Open Software License version 3.0 *
11 * http://www.opensource.org/licenses/osl-3.0.php *
12 ********************************************************************************
13 */
14
15 /**************************************************************/
16
17 /* Paso: SystemMatrix: controls iterative linear system solvers */
18
19 /**************************************************************/
20
21 /* Copyrights by ACcESS Australia 2003/04 */
22 /* Author: gross@access.edu.au */
23
24 /**************************************************************/
25
26 #include "Paso.h"
27 #include "SystemMatrix.h"
28 #include "Solver.h"
29 #include "escript/blocktimer.h"
30
31 /***********************************************************************************/
32
33 /* free space */
34
35 void Paso_Solver_free(Paso_SystemMatrix* A) {
36 Paso_Preconditioner_free(A->solver);
37 A->solver=NULL;
38 }
39 /* call the iterative solver: */
40
41 void Paso_Solver(Paso_SystemMatrix* A,double* x,double* b,Paso_Options* options,Paso_Performance* pp) {
42 double norm2_of_b,tol,tolerance,time_iter,*r=NULL,norm2_of_residual,last_norm2_of_residual,norm_max_of_b,
43 norm2_of_b_local,norm_max_of_b_local,norm2_of_residual_local,norm_max_of_residual_local,norm_max_of_residual,
44 last_norm_max_of_residual,*scaling, *buffer0, *buffer1, loc_norm;
45 dim_t i,totIter,cntIter,method;
46 bool_t finalizeIteration;
47 err_t errorCode;
48 dim_t myNumSol = A->myNumCols * A-> col_block_size;
49 dim_t maxNumSol = A->maxNumCols * A-> col_block_size;
50 dim_t myNumEqua = A->myNumRows * A-> row_block_size;
51 dim_t maxNumEqua = A->maxNumRows * A-> row_block_size;
52 double blocktimer_start = blocktimer_time();
53
54 tolerance=MAX(options->tolerance,EPSILON);
55 Paso_resetError();
56 method=Paso_Options_getSolver(options->method,PASO_PASO,options->symmetric);
57 /* check matrix type */
58 if ((A->type & MATRIX_FORMAT_CSC) || (A->type & MATRIX_FORMAT_OFFSET1) || (A->type & MATRIX_FORMAT_SYM) ) {
59 Paso_setError(TYPE_ERROR,"Iterative solver requires CSR format with unsymmetric storage scheme and index offset 0.");
60 }
61 if (A->col_block_size != A->row_block_size) {
62 Paso_setError(TYPE_ERROR,"Iterative solver requires row and column block sizes to be equal.");
63 }
64 if (A->numCols != A->numRows) {
65 Paso_setError(TYPE_ERROR,"Iterative solver requires requires a square matrix.");
66 return;
67 }
68 Performance_startMonitor(pp,PERFORMANCE_ALL);
69 if (Paso_noError()) {
70 /* get normalization */
71 scaling=Paso_SystemMatrix_borrowNormalization(A);
72 if (Paso_noError()) {
73 /* get the norm of the right hand side */
74 norm2_of_b=0.;
75 norm_max_of_b=0.;
76 #pragma omp parallel private(norm2_of_b_local,norm_max_of_b_local)
77 {
78 norm2_of_b_local=0.;
79 norm_max_of_b_local=0.;
80 #pragma omp for private(i) schedule(static)
81 for (i = 0; i < myNumEqua ; ++i) {
82 norm2_of_b_local += b[i] * b[i];
83 norm_max_of_b_local = MAX(ABS(scaling[i]*b[i]),norm_max_of_b_local);
84 }
85 #pragma omp critical
86 {
87 norm2_of_b += norm2_of_b_local;
88 norm_max_of_b = MAX(norm_max_of_b_local,norm_max_of_b);
89 }
90 }
91 /* TODO: use one call */
92 #ifdef PASO_MPI
93 {
94 loc_norm = norm2_of_b;
95 MPI_Allreduce(&loc_norm,&norm2_of_b, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
96 loc_norm = norm_max_of_b;
97 MPI_Allreduce(&loc_norm,&norm_max_of_b, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
98 }
99 #endif
100 norm2_of_b=sqrt(norm2_of_b);
101
102 /* if norm2_of_b==0 we are ready: x=0 */
103 if (norm2_of_b <=0.) {
104 #pragma omp parallel for private(i) schedule(static)
105 for (i = 0; i < myNumSol; i++) x[i]=0.;
106 if (options->verbose) printf("right hand side is identical zero.\n");
107 } else {
108 if (options->verbose) {
109 printf("l2/lmax-norm of right hand side is %e/%e.\n",norm2_of_b,norm_max_of_b);
110 printf("l2/lmax-stopping criterion is %e/%e.\n",norm2_of_b*tolerance,norm_max_of_b*tolerance);
111 switch (method) {
112 case PASO_BICGSTAB:
113 printf("Iterative method is BiCGStab.\n");
114 break;
115 case PASO_PCG:
116 printf("Iterative method is PCG.\n");
117 break;
118 case PASO_PRES20:
119 printf("Iterative method is PRES20.\n");
120 break;
121 case PASO_GMRES:
122 if (options->restart>0) {
123 printf("Iterative method is GMRES(%d,%d)\n",options->truncation,options->restart);
124 } else {
125 printf("Iterative method is GMRES(%d)\n",options->truncation);
126 }
127 break;
128 }
129 }
130 /* construct the preconditioner */
131
132 Performance_startMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
133 Paso_Solver_setPreconditioner(A,options);
134 Performance_stopMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
135 if (! Paso_noError()) return;
136
137 /* get an initial guess by evaluating the preconditioner */
138 time_iter=Paso_timer();
139 #pragma omp parallel
140 {
141 Paso_Solver_solvePreconditioner(A,x,b);
142 }
143 if (! Paso_noError()) return;
144 /* start the iteration process :*/
145 r=TMPMEMALLOC(maxNumEqua,double);
146 if (Paso_checkPtr(r)) return;
147 if (A->mpi_info->size>1) {
148 buffer1=TMPMEMALLOC(maxNumSol,double);
149 buffer0=TMPMEMALLOC(maxNumSol,double);
150 if (Paso_checkPtr(buffer1) || Paso_checkPtr(buffer0)) {
151 TMPMEMFREE(r);
152 MEMFREE(buffer0);
153 MEMFREE(buffer1);
154 return;
155 }
156 } else {
157 buffer0=NULL;
158 buffer1=NULL;
159 }
160 totIter = 0;
161 finalizeIteration = FALSE;
162 last_norm2_of_residual=norm2_of_b;
163 last_norm_max_of_residual=norm_max_of_b;
164 while (! finalizeIteration) {
165 cntIter = options->iter_max - totIter;
166 finalizeIteration = TRUE;
167 /* Set initial residual. */
168 norm2_of_residual = 0;
169 norm_max_of_residual = 0;
170 #pragma omp parallel private(norm2_of_residual_local,norm_max_of_residual_local)
171 {
172 #pragma omp for private(i) schedule(static)
173 for (i = 0; i < myNumEqua; i++) r[i]=b[i];
174
175 Paso_SystemMatrix_MatrixVector_CSR_OFFSET0(DBLE(-1), A, x, DBLE(1), r, buffer0, buffer1);
176
177 norm2_of_residual_local = 0;
178 norm_max_of_residual_local = 0;
179 #pragma omp for private(i) schedule(static)
180 for (i = 0; i < myNumEqua; i++) {
181 norm2_of_residual_local+= r[i] * r[i];
182 norm_max_of_residual_local=MAX(ABS(scaling[i]*r[i]),norm_max_of_residual_local);
183 }
184 #pragma omp critical
185 {
186 norm2_of_residual += norm2_of_residual_local;
187 norm_max_of_residual = MAX(norm_max_of_residual_local,norm_max_of_residual);
188 }
189 }
190 /* TODO: use one call */
191 #ifdef PASO_MPI
192 {
193 loc_norm = norm2_of_residual;
194 MPI_Allreduce(&loc_norm,&norm2_of_residual, 1, MPI_DOUBLE, MPI_SUM, A->mpi_info->comm);
195 loc_norm = norm_max_of_residual;
196 MPI_Allreduce(&loc_norm,&norm_max_of_residual, 1, MPI_DOUBLE, MPI_MAX, A->mpi_info->comm);
197 }
198 #endif
199 norm2_of_residual =sqrt(norm2_of_residual);
200
201 if (options->verbose) printf("Step %5d: l2/lmax-norm of residual is %e/%e",totIter,norm2_of_residual,norm_max_of_residual);
202 if (totIter>0 && norm2_of_residual>=last_norm2_of_residual && norm_max_of_residual>=last_norm_max_of_residual) {
203 if (options->verbose) printf(" divergence!\n");
204 Paso_setError(WARNING, "No improvement during iteration. Iterative solver gives up.");
205 } else {
206 /* */
207 if (norm2_of_residual>tolerance*norm2_of_b || norm_max_of_residual>tolerance*norm_max_of_b ) {
208 tol=tolerance*MIN(norm2_of_b,0.1*norm2_of_residual/norm_max_of_residual*norm_max_of_b);
209 if (options->verbose) printf(" (new tolerance = %e).\n",tol);
210 last_norm2_of_residual=norm2_of_residual;
211 last_norm_max_of_residual=norm_max_of_residual;
212 /* call the solver */
213 switch (method) {
214 case PASO_BICGSTAB:
215 errorCode = Paso_Solver_BiCGStab(A, r, x, &cntIter, &tol,buffer0, buffer1, pp);
216 break;
217 case PASO_PCG:
218 errorCode = Paso_Solver_PCG(A, r, x, &cntIter, &tol, buffer0, buffer1, pp);
219 break;
220 case PASO_PRES20:
221 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,5,20, buffer0, buffer1, pp);
222 break;
223 case PASO_GMRES:
224 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,options->truncation,options->restart, buffer0, buffer1, pp);
225 break;
226 }
227 totIter += cntIter;
228
229 /* error handling */
230 if (errorCode==NO_ERROR) {
231 finalizeIteration = FALSE;
232 } else if (errorCode==SOLVER_MAXITER_REACHED) {
233 Paso_setError(WARNING,"maximum number of iteration step reached.\nReturned solution does not fulfil stopping criterion.");
234 if (options->verbose) printf("Maximum number of iterations reached.!\n");
235 } else if (errorCode == SOLVER_INPUT_ERROR ) {
236 Paso_setError(SYSTEM_ERROR,"illegal dimension in iterative solver.");
237 if (options->verbose) printf("Internal error!\n");
238 } else if ( errorCode == SOLVER_BREAKDOWN ) {
239 if (cntIter <= 1) {
240 Paso_setError(ZERO_DIVISION_ERROR, "fatal break down in iterative solver.");
241 if (options->verbose) printf("Uncurable break down!\n");
242 } else {
243 if (options->verbose) printf("Breakdown at iter %d (residual = %e). Restarting ...\n", cntIter+totIter, tol);
244 finalizeIteration = FALSE;
245 }
246 } else if (errorCode == SOLVER_MEMORY_ERROR) {
247 Paso_setError(MEMORY_ERROR,"memory allocation failed.");
248 if (options->verbose) printf("Memory allocation failed!\n");
249 } else if (errorCode !=SOLVER_NO_ERROR ) {
250 Paso_setError(SYSTEM_ERROR,"unidentified error in iterative solver.");
251 if (options->verbose) printf("Unidentified error!\n");
252 }
253 } else {
254 if (options->verbose) printf(". convergence! \n");
255 }
256 }
257 } /* while */
258 MEMFREE(r);
259 MEMFREE(buffer0);
260 MEMFREE(buffer1);
261 time_iter=Paso_timer()-time_iter;
262 if (options->verbose) {
263 printf("timing: solver: %.4e sec\n",time_iter);
264 if (totIter>0) printf("timing: per iteration step: %.4e sec\n",time_iter/totIter);
265 }
266 }
267 }
268 }
269 Performance_stopMonitor(pp,PERFORMANCE_ALL);
270 blocktimer_increment("Paso_Solver()", blocktimer_start);
271 }

Properties

Name Value
svn:eol-style native
svn:keywords Author Date Id Revision

  ViewVC Help
Powered by ViewVC 1.1.26