1 #ifndef lint 2 static char vcid[] = "$Id: ls.c,v 1.87 1997/03/20 18:51:55 curfman Exp curfman $"; 3 #endif 4 5 #include <math.h> 6 #include "src/snes/impls/ls/ls.h" 7 #include "pinclude/pviewer.h" 8 9 /* 10 Implements a line search variant of Newton's Method 11 for solving systems of nonlinear equations. 12 13 Input parameters: 14 . snes - nonlinear context obtained from SNESCreate() 15 16 Output Parameters: 17 . outits - Number of global iterations until termination. 18 19 Notes: 20 This implements essentially a truncated Newton method with a 21 line search. By default a cubic backtracking line search 22 is employed, as described in the text "Numerical Methods for 23 Unconstrained Optimization and Nonlinear Equations" by Dennis 24 and Schnabel. 25 */ 26 27 #undef __FUNC__ 28 #define __FUNC__ "SNESSolve_EQ_LS" 29 int SNESSolve_EQ_LS(SNES snes,int *outits) 30 { 31 SNES_LS *neP = (SNES_LS *) snes->data; 32 int maxits, i, history_len, ierr, lits, lsfail; 33 MatStructure flg = DIFFERENT_NONZERO_PATTERN; 34 double fnorm, gnorm, xnorm, ynorm, *history; 35 Vec Y, X, F, G, W, TMP; 36 37 history = snes->conv_hist; /* convergence history */ 38 history_len = snes->conv_hist_size; /* convergence history length */ 39 maxits = snes->max_its; /* maximum number of iterations */ 40 X = snes->vec_sol; /* solution vector */ 41 F = snes->vec_func; /* residual vector */ 42 Y = snes->work[0]; /* work vectors */ 43 G = snes->work[1]; 44 W = snes->work[2]; 45 46 ierr = VecNorm(X,NORM_2,&xnorm); CHKERRQ(ierr); /* xnorm = || X || */ 47 snes->iter = 0; 48 ierr = SNESComputeFunction(snes,X,F); CHKERRQ(ierr); /* F(X) */ 49 ierr = VecNorm(F,NORM_2,&fnorm); CHKERRQ(ierr); /* fnorm <- ||F|| */ 50 snes->norm = fnorm; 51 if (history) history[0] = fnorm; 52 SNESMonitor(snes,0,fnorm); 53 54 if (fnorm == 0.0) {outits = 0; return 0;} 55 56 /* set parameter for default relative tolerance convergence test */ 57 snes->ttol = fnorm*snes->rtol; 58 59 for ( i=0; i<maxits; i++ ) { 60 snes->iter = i+1; 61 62 /* Solve J Y = F, where J is Jacobian matrix */ 63 ierr = SNESComputeJacobian(snes,X,&snes->jacobian,&snes->jacobian_pre,&flg); CHKERRQ(ierr); 64 ierr = SLESSetOperators(snes->sles,snes->jacobian,snes->jacobian_pre,flg); CHKERRQ(ierr); 65 ierr = SLESSolve(snes->sles,F,Y,&lits); CHKERRQ(ierr); 66 snes->linear_its += PetscAbsInt(lits); 67 PLogInfo(snes,"SNESSolve_EQ_LS: iter=%d, linear solve iterations=%d\n",snes->iter,lits); 68 69 /* Compute a (scaled) negative update in the line search routine: 70 Y <- X - lambda*Y 71 and evaluate G(Y) = function(Y)) 72 */ 73 ierr = VecCopy(Y,snes->vec_sol_update_always); CHKERRQ(ierr); 74 ierr = (*neP->LineSearch)(snes,X,F,G,Y,W,fnorm,&ynorm,&gnorm,&lsfail); CHKERRQ(ierr); 75 PLogInfo(snes,"SNESSolve_EQ_LS: fnorm=%g, gnorm=%g, ynorm=%g, lsfail=%d\n",fnorm,gnorm,ynorm,lsfail); 76 if (lsfail) snes->nfailures++; 77 78 TMP = F; F = G; snes->vec_func_always = F; G = TMP; 79 TMP = X; X = Y; snes->vec_sol_always = X; Y = TMP; 80 fnorm = gnorm; 81 82 snes->norm = fnorm; 83 if (history && history_len > i+1) history[i+1] = fnorm; 84 ierr = VecNorm(X,NORM_2,&xnorm); CHKERRQ(ierr); /* xnorm = || X || */ 85 SNESMonitor(snes,i+1,fnorm); 86 87 /* Test for convergence */ 88 if ((*snes->converged)(snes,xnorm,ynorm,fnorm,snes->cnvP)) { 89 break; 90 } 91 } 92 if (X != snes->vec_sol) { 93 ierr = VecCopy(X,snes->vec_sol); CHKERRQ(ierr); 94 snes->vec_sol_always = snes->vec_sol; 95 snes->vec_func_always = snes->vec_func; 96 } 97 if (i == maxits) { 98 PLogInfo(snes, 99 "SNESSolve_EQ_LS: Maximum number of iterations has been reached: %d\n",maxits); 100 i--; 101 } 102 if (history) snes->conv_act_size = (history_len < i+1) ? history_len : i+1; 103 *outits = i+1; 104 return 0; 105 } 106 /* ------------------------------------------------------------ */ 107 #undef __FUNC__ 108 #define __FUNC__ "SNESSetUp_EQ_LS" 109 int SNESSetUp_EQ_LS(SNES snes ) 110 { 111 int ierr; 112 snes->nwork = 4; 113 ierr = VecDuplicateVecs(snes->vec_sol,snes->nwork,&snes->work);CHKERRQ(ierr); 114 PLogObjectParents(snes,snes->nwork,snes->work); 115 snes->vec_sol_update_always = snes->work[3]; 116 return 0; 117 } 118 /* ------------------------------------------------------------ */ 119 #undef __FUNC__ 120 #define __FUNC__ "SNESDestroy_EQ_LS" /* ADIC Ignore */ 121 int SNESDestroy_EQ_LS(PetscObject obj) 122 { 123 SNES snes = (SNES) obj; 124 int ierr; 125 if (snes->nwork) { 126 ierr = VecDestroyVecs(snes->work,snes->nwork); CHKERRQ(ierr); 127 } 128 PetscFree(snes->data); 129 return 0; 130 } 131 /* ------------------------------------------------------------ */ 132 #undef __FUNC__ 133 #define __FUNC__ "SNESNoLineSearch" 134 /*ARGSUSED*/ 135 /*@C 136 SNESNoLineSearch - This routine is not a line search at all; 137 it simply uses the full Newton step. Thus, this routine is intended 138 to serve as a template and is not recommended for general use. 139 140 Input Parameters: 141 . snes - nonlinear context 142 . x - current iterate 143 . f - residual evaluated at x 144 . y - search direction (contains new iterate on output) 145 . w - work vector 146 . fnorm - 2-norm of f 147 148 Output Parameters: 149 . g - residual evaluated at new iterate y 150 . y - new iterate (contains search direction on input) 151 . gnorm - 2-norm of g 152 . ynorm - 2-norm of search length 153 . flag - set to 0, indicating a successful line search 154 155 Options Database Key: 156 $ -snes_eq_ls basic 157 158 .keywords: SNES, nonlinear, line search, cubic 159 160 .seealso: SNESCubicLineSearch(), SNESQuadraticLineSearch(), 161 SNESSetLineSearch() 162 @*/ 163 int SNESNoLineSearch(SNES snes, Vec x, Vec f, Vec g, Vec y, Vec w, 164 double fnorm, double *ynorm, double *gnorm,int *flag ) 165 { 166 int ierr; 167 Scalar mone = -1.0; 168 169 *flag = 0; 170 PLogEventBegin(SNES_LineSearch,snes,x,f,g); 171 ierr = VecNorm(y,NORM_2,ynorm); CHKERRQ(ierr); /* ynorm = || y || */ 172 ierr = VecAYPX(&mone,x,y); CHKERRQ(ierr); /* y <- y - x */ 173 ierr = SNESComputeFunction(snes,y,g); CHKERRQ(ierr); /* Compute F(y) */ 174 ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); /* gnorm = || g || */ 175 PLogEventEnd(SNES_LineSearch,snes,x,f,g); 176 return 0; 177 } 178 /* ------------------------------------------------------------------ */ 179 #undef __FUNC__ 180 #define __FUNC__ "SNESCubicLineSearch" 181 /*@C 182 SNESCubicLineSearch - Performs a cubic line search (default line search method). 183 184 Input Parameters: 185 . snes - nonlinear context 186 . x - current iterate 187 . f - residual evaluated at x 188 . y - search direction (contains new iterate on output) 189 . w - work vector 190 . fnorm - 2-norm of f 191 192 Output Parameters: 193 . g - residual evaluated at new iterate y 194 . y - new iterate (contains search direction on input) 195 . gnorm - 2-norm of g 196 . ynorm - 2-norm of search length 197 . flag - 0 if line search succeeds; -1 on failure. 198 199 Options Database Key: 200 $ -snes_eq_ls cubic 201 202 Notes: 203 This line search is taken from "Numerical Methods for Unconstrained 204 Optimization and Nonlinear Equations" by Dennis and Schnabel, page 325. 205 206 .keywords: SNES, nonlinear, line search, cubic 207 208 .seealso: SNESNoLineSearch(), SNESNoLineSearch(), SNESSetLineSearch() 209 @*/ 210 int SNESCubicLineSearch(SNES snes,Vec x,Vec f,Vec g,Vec y,Vec w, 211 double fnorm,double *ynorm,double *gnorm,int *flag) 212 { 213 double steptol, initslope, lambdaprev, gnormprev, a, b, d, t1, t2; 214 double maxstep, minlambda, alpha, lambda, lambdatemp, lambdaneg; 215 #if defined(PETSC_COMPLEX) 216 Scalar cinitslope, clambda; 217 #endif 218 int ierr, count; 219 SNES_LS *neP = (SNES_LS *) snes->data; 220 Scalar mone = -1.0,scale; 221 222 PLogEventBegin(SNES_LineSearch,snes,x,f,g); 223 *flag = 0; 224 alpha = neP->alpha; 225 maxstep = neP->maxstep; 226 steptol = neP->steptol; 227 228 ierr = VecNorm(y,NORM_2,ynorm); CHKERRQ(ierr); 229 if (*ynorm == 0.0) { 230 PLogInfo(snes,"SNESCubicLineSearch: Search direction and size is 0\n"); 231 goto theend1; 232 } 233 if (*ynorm > maxstep) { /* Step too big, so scale back */ 234 scale = maxstep/(*ynorm); 235 #if defined(PETSC_COMPLEX) 236 PLogInfo(snes,"SNESCubicLineSearch: Scaling step by %g\n",real(scale)); 237 #else 238 PLogInfo(snes,"SNESCubicLineSearch: Scaling step by %g\n",scale); 239 #endif 240 ierr = VecScale(&scale,y); CHKERRQ(ierr); 241 *ynorm = maxstep; 242 } 243 minlambda = steptol/(*ynorm); 244 ierr = MatMult(snes->jacobian,y,w); CHKERRQ(ierr); 245 #if defined(PETSC_COMPLEX) 246 ierr = VecDot(f,w,&cinitslope); CHKERRQ(ierr); 247 initslope = real(cinitslope); 248 #else 249 ierr = VecDot(f,w,&initslope); CHKERRQ(ierr); 250 #endif 251 if (initslope > 0.0) initslope = -initslope; 252 if (initslope == 0.0) initslope = -1.0; 253 254 ierr = VecCopy(y,w); CHKERRQ(ierr); 255 ierr = VecAYPX(&mone,x,w); CHKERRQ(ierr); 256 ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); 257 ierr = VecNorm(g,NORM_2,gnorm); 258 if (*gnorm <= fnorm + alpha*initslope) { /* Sufficient reduction */ 259 ierr = VecCopy(w,y); CHKERRQ(ierr); 260 PLogInfo(snes,"SNESCubicLineSearch: Using full step\n"); 261 goto theend1; 262 } 263 264 /* Fit points with quadratic */ 265 lambda = 1.0; count = 0; 266 lambdatemp = -initslope/((*gnorm)*(*gnorm) - fnorm*fnorm - 2.0*initslope); 267 lambdaprev = lambda; 268 gnormprev = *gnorm; 269 if (lambdatemp <= .1*lambda) lambda = .1*lambda; 270 else lambda = lambdatemp; 271 ierr = VecCopy(x,w); CHKERRQ(ierr); 272 lambdaneg = -lambda; 273 #if defined(PETSC_COMPLEX) 274 clambda = lambdaneg; ierr = VecAXPY(&clambda,y,w); CHKERRQ(ierr); 275 #else 276 ierr = VecAXPY(&lambdaneg,y,w); CHKERRQ(ierr); 277 #endif 278 ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); 279 ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); 280 if (*gnorm <= fnorm + alpha*initslope) { /* sufficient reduction */ 281 ierr = VecCopy(w,y); CHKERRQ(ierr); 282 PLogInfo(snes,"SNESCubicLineSearch: Quadratically determined step, lambda=%g\n",lambda); 283 goto theend1; 284 } 285 286 /* Fit points with cubic */ 287 count = 1; 288 while (1) { 289 if (lambda <= minlambda) { /* bad luck; use full step */ 290 PLogInfo(snes, 291 "SNESCubicLineSearch:Unable to find good step length! %d \n",count); 292 PLogInfo(snes, 293 "SNESCubicLineSearch:fnorm=%g, gnorm=%g, ynorm=%g, lambda=%g, initial slope=%g\n", 294 fnorm,*gnorm,*ynorm,lambda,initslope); 295 ierr = VecCopy(w,y); CHKERRQ(ierr); 296 *flag = -1; break; 297 } 298 t1 = *gnorm - fnorm - lambda*initslope; 299 t2 = gnormprev - fnorm - lambdaprev*initslope; 300 a = (t1/(lambda*lambda) - t2/(lambdaprev*lambdaprev))/(lambda-lambdaprev); 301 b = (-lambdaprev*t1/(lambda*lambda) + 302 lambda*t2/(lambdaprev*lambdaprev))/(lambda-lambdaprev); 303 d = b*b - 3*a*initslope; 304 if (d < 0.0) d = 0.0; 305 if (a == 0.0) { 306 lambdatemp = -initslope/(2.0*b); 307 } else { 308 lambdatemp = (-b + sqrt(d))/(3.0*a); 309 } 310 if (lambdatemp > .5*lambda) { 311 lambdatemp = .5*lambda; 312 } 313 lambdaprev = lambda; 314 gnormprev = *gnorm; 315 if (lambdatemp <= .1*lambda) { 316 lambda = .1*lambda; 317 } 318 else lambda = lambdatemp; 319 ierr = VecCopy( x, w ); CHKERRQ(ierr); 320 lambdaneg = -lambda; 321 #if defined(PETSC_COMPLEX) 322 clambda = lambdaneg; 323 ierr = VecAXPY(&clambda,y,w); CHKERRQ(ierr); 324 #else 325 ierr = VecAXPY(&lambdaneg,y,w); CHKERRQ(ierr); 326 #endif 327 ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); 328 ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); 329 if (*gnorm <= fnorm + alpha*initslope) { /* is reduction enough */ 330 ierr = VecCopy(w,y); CHKERRQ(ierr); 331 PLogInfo(snes,"SNESCubicLineSearch: Cubically determined step, lambda=%g\n",lambda); 332 goto theend1; 333 } 334 count++; 335 } 336 theend1: 337 PLogEventEnd(SNES_LineSearch,snes,x,f,g); 338 return 0; 339 } 340 /* ------------------------------------------------------------------ */ 341 #undef __FUNC__ 342 #define __FUNC__ "SNESQuadraticLineSearch" 343 /*@C 344 SNESQuadraticLineSearch - Performs a quadratic line search. 345 346 Input Parameters: 347 . snes - the SNES context 348 . x - current iterate 349 . f - residual evaluated at x 350 . y - search direction (contains new iterate on output) 351 . w - work vector 352 . fnorm - 2-norm of f 353 354 Output Parameters: 355 . g - residual evaluated at new iterate y 356 . y - new iterate (contains search direction on input) 357 . gnorm - 2-norm of g 358 . ynorm - 2-norm of search length 359 . flag - 0 if line search succeeds; -1 on failure. 360 361 Options Database Key: 362 $ -snes_eq_ls quadratic 363 364 Notes: 365 Use SNESSetLineSearch() 366 to set this routine within the SNES_EQ_LS method. 367 368 .keywords: SNES, nonlinear, quadratic, line search 369 370 .seealso: SNESCubicLineSearch(), SNESNoLineSearch(), SNESSetLineSearch() 371 @*/ 372 int SNESQuadraticLineSearch(SNES snes, Vec x, Vec f, Vec g, Vec y, Vec w, 373 double fnorm, double *ynorm, double *gnorm,int *flag) 374 { 375 double steptol,initslope,lambdaprev,gnormprev,maxstep,minlambda,alpha,lambda,lambdatemp; 376 #if defined(PETSC_COMPLEX) 377 Scalar cinitslope,clambda; 378 #endif 379 int ierr,count; 380 SNES_LS *neP = (SNES_LS *) snes->data; 381 Scalar mone = -1.0,scale; 382 383 PLogEventBegin(SNES_LineSearch,snes,x,f,g); 384 *flag = 0; 385 alpha = neP->alpha; 386 maxstep = neP->maxstep; 387 steptol = neP->steptol; 388 389 VecNorm(y, NORM_2,ynorm ); 390 if (*ynorm == 0.0) { 391 PLogInfo(snes,"SNESQuadraticLineSearch: Search direction and size is 0\n"); 392 goto theend2; 393 } 394 if (*ynorm > maxstep) { /* Step too big, so scale back */ 395 scale = maxstep/(*ynorm); 396 ierr = VecScale(&scale,y); CHKERRQ(ierr); 397 *ynorm = maxstep; 398 } 399 minlambda = steptol/(*ynorm); 400 ierr = MatMult(snes->jacobian,y,w); CHKERRQ(ierr); 401 #if defined(PETSC_COMPLEX) 402 ierr = VecDot(f,w,&cinitslope); CHKERRQ(ierr); 403 initslope = real(cinitslope); 404 #else 405 ierr = VecDot(f,w,&initslope); CHKERRQ(ierr); 406 #endif 407 if (initslope > 0.0) initslope = -initslope; 408 if (initslope == 0.0) initslope = -1.0; 409 410 ierr = VecCopy(y,w); CHKERRQ(ierr); 411 ierr = VecAYPX(&mone,x,w); CHKERRQ(ierr); 412 ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); 413 ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); 414 if (*gnorm <= fnorm + alpha*initslope) { /* Sufficient reduction */ 415 ierr = VecCopy(w,y); CHKERRQ(ierr); 416 PLogInfo(snes,"SNESQuadraticLineSearch: Using full step\n"); 417 goto theend2; 418 } 419 420 /* Fit points with quadratic */ 421 lambda = 1.0; count = 0; 422 count = 1; 423 while (1) { 424 if (lambda <= minlambda) { /* bad luck; use full step */ 425 PLogInfo(snes, 426 "SNESQuadraticLineSearch:Unable to find good step length! %d \n",count); 427 PLogInfo(snes, 428 "SNESQuadraticLineSearch:fnorm=%g, gnorm=%g, ynorm=%g, lambda=%g, initial slope=%g\n", 429 fnorm,*gnorm,*ynorm,lambda,initslope); 430 ierr = VecCopy(w,y); CHKERRQ(ierr); 431 *flag = -1; break; 432 } 433 lambdatemp = -initslope/((*gnorm)*(*gnorm) - fnorm*fnorm - 2.0*initslope); 434 lambdaprev = lambda; 435 gnormprev = *gnorm; 436 if (lambdatemp <= .1*lambda) { 437 lambda = .1*lambda; 438 } else lambda = lambdatemp; 439 ierr = VecCopy(x,w); CHKERRQ(ierr); 440 lambda = -lambda; 441 #if defined(PETSC_COMPLEX) 442 clambda = lambda; ierr = VecAXPY(&clambda,y,w); CHKERRQ(ierr); 443 #else 444 ierr = VecAXPY(&lambda,y,w); CHKERRQ(ierr); 445 #endif 446 ierr = SNESComputeFunction(snes,w,g); CHKERRQ(ierr); 447 ierr = VecNorm(g,NORM_2,gnorm); CHKERRQ(ierr); 448 if (*gnorm <= fnorm + alpha*initslope) { /* sufficient reduction */ 449 ierr = VecCopy(w,y); CHKERRQ(ierr); 450 PLogInfo(snes, 451 "SNESQuadraticLineSearch:Quadratically determined step, lambda=%g\n",lambda); 452 break; 453 } 454 count++; 455 } 456 theend2: 457 PLogEventEnd(SNES_LineSearch,snes,x,f,g); 458 return 0; 459 } 460 /* ------------------------------------------------------------ */ 461 #undef __FUNC__ 462 #define __FUNC__ "SNESSetLineSearch" /* ADIC Ignore */ 463 /*@C 464 SNESSetLineSearch - Sets the line search routine to be used 465 by the method SNES_EQ_LS. 466 467 Input Parameters: 468 . snes - nonlinear context obtained from SNESCreate() 469 . func - pointer to int function 470 471 Available Routines: 472 . SNESCubicLineSearch() - default line search 473 . SNESQuadraticLineSearch() - quadratic line search 474 . SNESNoLineSearch() - the full Newton step (actually not a line search) 475 476 Options Database Keys: 477 $ -snes_eq_ls [basic,quadratic,cubic] 478 $ -snes_eq_ls_alpha <alpha> 479 $ -snes_eq_ls_maxstep <max> 480 $ -snes_eq_ls_steptol <steptol> 481 482 Calling sequence of func: 483 func (SNES snes, Vec x, Vec f, Vec g, Vec y, 484 Vec w, double fnorm, double *ynorm, 485 double *gnorm, *flag) 486 487 Input parameters for func: 488 . snes - nonlinear context 489 . x - current iterate 490 . f - residual evaluated at x 491 . y - search direction (contains new iterate on output) 492 . w - work vector 493 . fnorm - 2-norm of f 494 495 Output parameters for func: 496 . g - residual evaluated at new iterate y 497 . y - new iterate (contains search direction on input) 498 . gnorm - 2-norm of g 499 . ynorm - 2-norm of search length 500 . flag - set to 0 if the line search succeeds; a nonzero integer 501 on failure. 502 503 .keywords: SNES, nonlinear, set, line search, routine 504 505 .seealso: SNESNoLineSearch(), SNESQuadraticLineSearch(), SNESCubicLineSearch() 506 @*/ 507 int SNESSetLineSearch(SNES snes,int (*func)(SNES,Vec,Vec,Vec,Vec,Vec, 508 double,double*,double*,int*)) 509 { 510 if ((snes)->type == SNES_EQ_LS) ((SNES_LS *)(snes->data))->LineSearch = func; 511 return 0; 512 } 513 /* ------------------------------------------------------------------ */ 514 #undef __FUNC__ 515 #define __FUNC__ "SNESPrintHelp_EQ_LS" /* ADIC Ignore */ 516 static int SNESPrintHelp_EQ_LS(SNES snes,char *p) 517 { 518 SNES_LS *ls = (SNES_LS *)snes->data; 519 520 PetscPrintf(snes->comm," method SNES_EQ_LS (ls) for systems of nonlinear equations:\n"); 521 PetscPrintf(snes->comm," %ssnes_eq_ls [basic,quadratic,cubic]\n",p); 522 PetscPrintf(snes->comm," %ssnes_eq_ls_alpha <alpha> (default %g)\n",p,ls->alpha); 523 PetscPrintf(snes->comm," %ssnes_eq_ls_maxstep <max> (default %g)\n",p,ls->maxstep); 524 PetscPrintf(snes->comm," %ssnes_eq_ls_steptol <tol> (default %g)\n",p,ls->steptol); 525 return 0; 526 } 527 /* ------------------------------------------------------------------ */ 528 #undef __FUNC__ 529 #define __FUNC__ "SNESView_EQ_LS" /* ADIC Ignore */ 530 static int SNESView_EQ_LS(PetscObject obj,Viewer viewer) 531 { 532 SNES snes = (SNES)obj; 533 SNES_LS *ls = (SNES_LS *)snes->data; 534 FILE *fd; 535 char *cstr; 536 int ierr; 537 ViewerType vtype; 538 539 ierr = ViewerGetType(viewer,&vtype); CHKERRQ(ierr); 540 if (vtype == ASCII_FILE_VIEWER || vtype == ASCII_FILES_VIEWER) { 541 ierr = ViewerASCIIGetPointer(viewer,&fd); CHKERRQ(ierr); 542 if (ls->LineSearch == SNESNoLineSearch) cstr = "SNESNoLineSearch"; 543 else if (ls->LineSearch == SNESQuadraticLineSearch) cstr = "SNESQuadraticLineSearch"; 544 else if (ls->LineSearch == SNESCubicLineSearch) cstr = "SNESCubicLineSearch"; 545 else cstr = "unknown"; 546 PetscFPrintf(snes->comm,fd," line search variant: %s\n",cstr); 547 PetscFPrintf(snes->comm,fd," alpha=%g, maxstep=%g, steptol=%g\n", 548 ls->alpha,ls->maxstep,ls->steptol); 549 } 550 return 0; 551 } 552 /* ------------------------------------------------------------------ */ 553 #undef __FUNC__ 554 #define __FUNC__ "SNESSetFromOptions_EQ_LS" 555 static int SNESSetFromOptions_EQ_LS(SNES snes) 556 { 557 SNES_LS *ls = (SNES_LS *)snes->data; 558 char ver[16]; 559 double tmp; 560 int ierr,flg; 561 562 ierr = OptionsGetDouble(snes->prefix,"-snes_eq_ls_alpha",&tmp, &flg);CHKERRQ(ierr); 563 if (flg) { 564 ls->alpha = tmp; 565 } 566 ierr = OptionsGetDouble(snes->prefix,"-snes_eq_ls_maxstep",&tmp, &flg);CHKERRQ(ierr); 567 if (flg) { 568 ls->maxstep = tmp; 569 } 570 ierr = OptionsGetDouble(snes->prefix,"-snes_eq_ls_steptol",&tmp, &flg);CHKERRQ(ierr); 571 if (flg) { 572 ls->steptol = tmp; 573 } 574 ierr = OptionsGetString(snes->prefix,"-snes_eq_ls",ver,16, &flg); CHKERRQ(ierr); 575 if (flg) { 576 if (!PetscStrcmp(ver,"basic")) { 577 SNESSetLineSearch(snes,SNESNoLineSearch); 578 } 579 else if (!PetscStrcmp(ver,"quadratic")) { 580 SNESSetLineSearch(snes,SNESQuadraticLineSearch); 581 } 582 else if (!PetscStrcmp(ver,"cubic")) { 583 SNESSetLineSearch(snes,SNESCubicLineSearch); 584 } 585 else {SETERRQ(1,0,"Unknown line search");} 586 } 587 return 0; 588 } 589 /* ------------------------------------------------------------ */ 590 #undef __FUNC__ 591 #define __FUNC__ "SNESCreate_EQ_LS" 592 int SNESCreate_EQ_LS(SNES snes ) 593 { 594 SNES_LS *neP; 595 596 if (snes->method_class != SNES_NONLINEAR_EQUATIONS) 597 SETERRQ(1,0,"For SNES_NONLINEAR_EQUATIONS only"); 598 snes->type = SNES_EQ_LS; 599 snes->setup = SNESSetUp_EQ_LS; 600 snes->solve = SNESSolve_EQ_LS; 601 snes->destroy = SNESDestroy_EQ_LS; 602 snes->converged = SNESConverged_EQ_LS; 603 snes->printhelp = SNESPrintHelp_EQ_LS; 604 snes->setfromoptions = SNESSetFromOptions_EQ_LS; 605 snes->view = SNESView_EQ_LS; 606 snes->nwork = 0; 607 608 neP = PetscNew(SNES_LS); CHKPTRQ(neP); 609 PLogObjectMemory(snes,sizeof(SNES_LS)); 610 snes->data = (void *) neP; 611 neP->alpha = 1.e-4; 612 neP->maxstep = 1.e8; 613 neP->steptol = 1.e-12; 614 neP->LineSearch = SNESCubicLineSearch; 615 return 0; 616 } 617 618