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

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Revision 700 - (show annotations)
Thu Apr 6 00:13:40 2006 UTC (13 years, 8 months ago) by gross
File MIME type: text/plain
File size: 11607 byte(s)
A few changes in the build mechanism and the file structure so scons can build release tar files:

  * paso/src/Solver has been moved to paso/src 
  * all test_.py are now run_.py files and are assumed to be passing python tests. they can run by 
    scons py_tests and are part of the release test set
  * escript/py_src/test_ are moved to escript/test/python and are installed in to the build directory 
    (rather then the PYTHONPATH).
  * all py files in test/python which don't start with run_ or test_ are now 'local_py_tests'. they are installed i
    by not run automatically.
  * CppUnitTest is now treated as a escript module (against previous decisions).
  * scons realse builds nor tar/zip files with relvant source code (src and tests in seperate files)

the python tests don't pass yet due to path problems.


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
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,Paso_Options* options,Paso_Performance* pp) {
41 double norm2_of_b,tol,tolerance,time_iter,*r=NULL,norm2_of_residual,last_norm2_of_residual,norm_max_of_b,
42 norm2_of_b_local,norm_max_of_b_local,norm2_of_residual_local,norm_max_of_residual_local,norm_max_of_residual,
43 last_norm_max_of_residual,*scaling;
44 dim_t i,totIter,cntIter,method;
45 bool_t finalizeIteration;
46 err_t errorCode;
47 dim_t n_col = A->num_cols * A-> col_block_size;
48 dim_t n_row = A->num_rows * A-> row_block_size;
49
50 tolerance=MAX(options->tolerance,EPSILON);
51 Paso_resetError();
52 method=Paso_Options_getSolver(options->method,PASO_PASO,options->symmetric);
53 /* check matrix type */
54 if ((A->type & MATRIX_FORMAT_CSC) || (A->type & MATRIX_FORMAT_OFFSET1) || (A->type & MATRIX_FORMAT_SYM) ) {
55 Paso_setError(TYPE_ERROR,"Iterative solver requires CSR format with unsymmetric storage scheme and index offset 0.");
56 }
57 if (A->col_block_size != A->row_block_size) {
58 Paso_setError(TYPE_ERROR,"Iterative solver requires row and column block sizes to be equal.");
59 }
60 if (A->num_cols != A->num_rows) {
61 Paso_setError(TYPE_ERROR,"Iterative solver requires requires a square matrix.");
62 return;
63 }
64 Performance_startMonitor(pp,PERFORMANCE_ALL);
65 if (Paso_noError()) {
66 /* get normalization */
67 scaling=Paso_SystemMatrix_borrowNormalization(A);
68 if (Paso_noError()) {
69 /* get the norm of the right hand side */
70 norm2_of_b=0.;
71 norm_max_of_b=0.;
72 #pragma omp parallel private(norm2_of_b_local,norm_max_of_b_local)
73 {
74 norm2_of_b_local=0.;
75 norm_max_of_b_local=0.;
76 #pragma omp for private(i) schedule(static)
77 for (i = 0; i < n_row ; ++i) {
78 norm2_of_b_local += b[i] * b[i];
79 norm_max_of_b_local = MAX(ABS(scaling[i]*b[i]),norm_max_of_b_local);
80 }
81 #pragma omp critical
82 {
83 norm2_of_b += norm2_of_b_local;
84 norm_max_of_b = MAX(norm_max_of_b_local,norm_max_of_b);
85 }
86 }
87 norm2_of_b=sqrt(norm2_of_b);
88
89 /* if norm2_of_b==0 we are ready: x=0 */
90 if (norm2_of_b <=0.) {
91 #pragma omp parallel for private(i) schedule(static)
92 for (i = 0; i < n_col; i++) x[i]=0.;
93 if (options->verbose) printf("right hand side is identical zero.\n");
94 } else {
95 if (options->verbose) {
96 printf("l2/lmax-norm of right hand side is %e/%e.\n",norm2_of_b,norm_max_of_b);
97 printf("l2/lmax-stopping criterion is %e/%e.\n",norm2_of_b*tolerance,norm_max_of_b*tolerance);
98 switch (method) {
99 case PASO_BICGSTAB:
100 printf("Iterative method is BiCGStab.\n");
101 break;
102 case PASO_PCG:
103 printf("Iterative method is PCG.\n");
104 break;
105 case PASO_PRES20:
106 printf("Iterative method is PRES20.\n");
107 break;
108 case PASO_GMRES:
109 if (options->restart>0) {
110 printf("Iterative method is GMRES(%d,%d)\n",options->truncation,options->restart);
111 } else {
112 printf("Iterative method is GMRES(%d)\n",options->truncation);
113 }
114 break;
115 }
116 }
117 /* construct the preconditioner */
118
119 Performance_startMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
120 Paso_Solver_setPreconditioner(A,options);
121 Performance_stopMonitor(pp,PERFORMANCE_PRECONDITIONER_INIT);
122 if (! Paso_noError()) return;
123
124 /* get an initial guess by evaluating the preconditioner */
125 time_iter=Paso_timer();
126 #pragma omp parallel
127 Paso_Solver_solvePreconditioner(A,x,b);
128 if (! Paso_noError()) return;
129 /* start the iteration process :*/
130 r=TMPMEMALLOC(n_row,double);
131 if (Paso_checkPtr(r)) return;
132 totIter = 0;
133 finalizeIteration = FALSE;
134 last_norm2_of_residual=norm2_of_b;
135 last_norm_max_of_residual=norm_max_of_b;
136 while (! finalizeIteration) {
137 cntIter = options->iter_max - totIter;
138 finalizeIteration = TRUE;
139 /* Set initial residual. */
140 norm2_of_residual = 0;
141 norm_max_of_residual = 0;
142 #pragma omp parallel private(norm2_of_residual_local,norm_max_of_residual_local)
143 {
144 #pragma omp for private(i) schedule(static)
145 for (i = 0; i < n_row; i++) r[i]=b[i];
146
147 Paso_SystemMatrix_MatrixVector_CSR_OFFSET0(DBLE(-1), A, x, DBLE(1), r);
148
149 norm2_of_residual_local = 0;
150 norm_max_of_residual_local = 0;
151 #pragma omp for private(i) schedule(static)
152 for (i = 0; i < n_row; i++) {
153 norm2_of_residual_local+= r[i] * r[i];
154 norm_max_of_residual_local=MAX(ABS(scaling[i]*r[i]),norm_max_of_residual_local);
155 }
156 #pragma omp critical
157 {
158 norm2_of_residual += norm2_of_residual_local;
159 norm_max_of_residual = MAX(norm_max_of_residual_local,norm_max_of_residual);
160 }
161 }
162 norm2_of_residual =sqrt(norm2_of_residual);
163
164 if (options->verbose) printf("Step %5d: l2/lmax-norm of residual is %e/%e",totIter,norm2_of_residual,norm_max_of_residual);
165 if (totIter>0 && norm2_of_residual>=last_norm2_of_residual && norm_max_of_residual>=last_norm_max_of_residual) {
166 if (options->verbose) printf(" divergence!\n");
167 Paso_setError(WARNING, "No improvement during iteration. Iterative solver gives up.");
168 } else {
169 /* */
170 if (norm2_of_residual>tolerance*norm2_of_b || norm_max_of_residual>tolerance*norm_max_of_b ) {
171 tol=tolerance*MIN(norm2_of_b,0.1*norm2_of_residual/norm_max_of_residual*norm_max_of_b);
172 if (options->verbose) printf(" (new tolerance = %e).\n",tol);
173 last_norm2_of_residual=norm2_of_residual;
174 last_norm_max_of_residual=norm_max_of_residual;
175 /* call the solver */
176 switch (method) {
177 case PASO_BICGSTAB:
178 errorCode = Paso_Solver_BiCGStab(A, r, x, &cntIter, &tol,pp);
179 break;
180 case PASO_PCG:
181 errorCode = Paso_Solver_PCG(A, r, x, &cntIter, &tol,pp);
182 break;
183 case PASO_PRES20:
184 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,5,20,pp);
185 break;
186 case PASO_GMRES:
187 errorCode = Paso_Solver_GMRES(A, r, x, &cntIter, &tol,options->truncation,options->restart,pp);
188 break;
189 }
190 totIter += cntIter;
191
192 /* error handling */
193 if (errorCode==NO_ERROR) {
194 finalizeIteration = FALSE;
195 } else if (errorCode==SOLVER_MAXITER_REACHED) {
196 Paso_setError(WARNING,"maximum number of iteration step reached.\nReturned solution does not fulfil stopping criterion.");
197 if (options->verbose) printf("Maximum number of iterations reached.!\n");
198 } else if (errorCode == SOLVER_INPUT_ERROR ) {
199 Paso_setError(SYSTEM_ERROR,"illegal dimension in iterative solver.");
200 if (options->verbose) printf("Internal error!\n");
201 } else if ( errorCode == SOLVER_BREAKDOWN ) {
202 if (cntIter <= 1) {
203 Paso_setError(ZERO_DIVISION_ERROR, "fatal break down in iterative solver.");
204 if (options->verbose) printf("Uncurable break down!\n");
205 } else {
206 if (options->verbose) printf("Breakdown at iter %d (residual = %e). Restarting ...\n", cntIter+totIter, tol);
207 finalizeIteration = FALSE;
208 }
209 } else if (errorCode == SOLVER_MEMORY_ERROR) {
210 Paso_setError(MEMORY_ERROR,"memory allocation failed.");
211 if (options->verbose) printf("Memory allocation failed!\n");
212 } else if (errorCode !=SOLVER_NO_ERROR ) {
213 Paso_setError(SYSTEM_ERROR,"unidentified error in iterative solver.");
214 if (options->verbose) printf("Unidentified error!\n");
215 }
216 } else {
217 if (options->verbose) printf(". convergence! \n");
218 }
219 }
220 } /* while */
221 MEMFREE(r);
222 time_iter=Paso_timer()-time_iter;
223 if (options->verbose) {
224 printf("timing: solver: %.4e sec\n",time_iter);
225 if (totIter>0) printf("timing: per iteration step: %.4e sec\n",time_iter/totIter);
226 }
227 }
228 }
229 }
230 Performance_stopMonitor(pp,PERFORMANCE_ALL);
231 }

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