1 #include <../src/snes/impls/ncg/snesncgimpl.h> /*I "petscsnes.h" I*/ 2 const char *const SNESNCGTypes[] = {"FR","PRP","HS","DY","CD","SNESNCGType","SNES_NCG_",0}; 3 4 PetscErrorCode SNESReset_NCG(SNES snes) 5 { 6 PetscFunctionBegin; 7 PetscFunctionReturn(0); 8 } 9 10 #define SNESLINESEARCHNCGLINEAR "ncglinear" 11 12 /* 13 SNESDestroy_NCG - Destroys the private SNES_NCG context that was created with SNESCreate_NCG(). 14 15 Input Parameter: 16 . snes - the SNES context 17 18 Application Interface Routine: SNESDestroy() 19 */ 20 PetscErrorCode SNESDestroy_NCG(SNES snes) 21 { 22 PetscErrorCode ierr; 23 24 PetscFunctionBegin; 25 ierr = PetscFree(snes->data);CHKERRQ(ierr); 26 PetscFunctionReturn(0); 27 } 28 29 /* 30 SNESSetUp_NCG - Sets up the internal data structures for the later use 31 of the SNESNCG nonlinear solver. 32 33 Input Parameters: 34 + snes - the SNES context 35 - x - the solution vector 36 37 Application Interface Routine: SNESSetUp() 38 */ 39 40 PETSC_EXTERN PetscErrorCode SNESLineSearchCreate_NCGLinear(SNESLineSearch); 41 42 PetscErrorCode SNESSetUp_NCG(SNES snes) 43 { 44 PetscErrorCode ierr; 45 46 PetscFunctionBegin; 47 ierr = SNESSetWorkVecs(snes,2);CHKERRQ(ierr); 48 if (snes->npcside== PC_RIGHT) SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE, "SNESNCG only supports left preconditioning"); 49 if (snes->functype == SNES_FUNCTION_DEFAULT) snes->functype = SNES_FUNCTION_UNPRECONDITIONED; 50 PetscFunctionReturn(0); 51 } 52 /* 53 SNESSetFromOptions_NCG - Sets various parameters for the SNESNCG method. 54 55 Input Parameter: 56 . snes - the SNES context 57 58 Application Interface Routine: SNESSetFromOptions() 59 */ 60 static PetscErrorCode SNESSetFromOptions_NCG(PetscOptionItems *PetscOptionsObject,SNES snes) 61 { 62 SNES_NCG *ncg = (SNES_NCG*)snes->data; 63 PetscErrorCode ierr; 64 PetscBool debug = PETSC_FALSE; 65 SNESLineSearch linesearch; 66 SNESNCGType ncgtype=ncg->type; 67 68 PetscFunctionBegin; 69 ierr = PetscOptionsHead(PetscOptionsObject,"SNES NCG options");CHKERRQ(ierr); 70 ierr = PetscOptionsBool("-snes_ncg_monitor","Monitor NCG iterations","SNES",ncg->monitor ? PETSC_TRUE : PETSC_FALSE, &debug, NULL);CHKERRQ(ierr); 71 if (debug) { 72 ncg->monitor = PETSC_VIEWER_STDOUT_(PetscObjectComm((PetscObject)snes));CHKERRQ(ierr); 73 } 74 ierr = PetscOptionsEnum("-snes_ncg_type","NCG Beta type used","SNESNCGSetType",SNESNCGTypes,(PetscEnum)ncg->type,(PetscEnum*)&ncgtype,NULL);CHKERRQ(ierr); 75 ierr = SNESNCGSetType(snes, ncgtype);CHKERRQ(ierr); 76 ierr = PetscOptionsTail();CHKERRQ(ierr); 77 if (!snes->linesearch) { 78 ierr = SNESGetLineSearch(snes, &linesearch);CHKERRQ(ierr); 79 if (!snes->npc) { 80 ierr = SNESLineSearchSetType(linesearch, SNESLINESEARCHCP);CHKERRQ(ierr); 81 } else { 82 ierr = SNESLineSearchSetType(linesearch, SNESLINESEARCHL2);CHKERRQ(ierr); 83 } 84 } 85 ierr = SNESLineSearchRegister(SNESLINESEARCHNCGLINEAR, SNESLineSearchCreate_NCGLinear);CHKERRQ(ierr); 86 PetscFunctionReturn(0); 87 } 88 89 /* 90 SNESView_NCG - Prints info from the SNESNCG data structure. 91 92 Input Parameters: 93 + SNES - the SNES context 94 - viewer - visualization context 95 96 Application Interface Routine: SNESView() 97 */ 98 static PetscErrorCode SNESView_NCG(SNES snes, PetscViewer viewer) 99 { 100 SNES_NCG *ncg = (SNES_NCG *) snes->data; 101 PetscBool iascii; 102 PetscErrorCode ierr; 103 104 PetscFunctionBegin; 105 ierr = PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERASCII, &iascii);CHKERRQ(ierr); 106 if (iascii) { 107 ierr = PetscViewerASCIIPrintf(viewer, " type: %s\n", SNESNCGTypes[ncg->type]);CHKERRQ(ierr); 108 } 109 PetscFunctionReturn(0); 110 } 111 112 PetscErrorCode SNESLineSearchApply_NCGLinear(SNESLineSearch linesearch) 113 { 114 PetscScalar alpha, ptAp; 115 Vec X, Y, F, W; 116 SNES snes; 117 PetscErrorCode ierr; 118 PetscReal *fnorm, *xnorm, *ynorm; 119 120 PetscFunctionBegin; 121 ierr = SNESLineSearchGetSNES(linesearch, &snes);CHKERRQ(ierr); 122 X = linesearch->vec_sol; 123 W = linesearch->vec_sol_new; 124 F = linesearch->vec_func; 125 Y = linesearch->vec_update; 126 fnorm = &linesearch->fnorm; 127 xnorm = &linesearch->xnorm; 128 ynorm = &linesearch->ynorm; 129 130 if (!snes->jacobian) { 131 ierr = SNESSetUpMatrices(snes);CHKERRQ(ierr); 132 } 133 134 /* 135 136 The exact step size for unpreconditioned linear CG is just: 137 alpha = (r, r) / (p, Ap) = (f, f) / (y, Jy) 138 */ 139 ierr = SNESComputeJacobian(snes, X, snes->jacobian, snes->jacobian_pre);CHKERRQ(ierr); 140 ierr = VecDot(F, F, &alpha);CHKERRQ(ierr); 141 ierr = MatMult(snes->jacobian, Y, W);CHKERRQ(ierr); 142 ierr = VecDot(Y, W, &ptAp);CHKERRQ(ierr); 143 alpha = alpha / ptAp; 144 ierr = VecAXPY(X,-alpha,Y);CHKERRQ(ierr); 145 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 146 147 ierr = VecNorm(F,NORM_2,fnorm);CHKERRQ(ierr); 148 ierr = VecNorm(X,NORM_2,xnorm);CHKERRQ(ierr); 149 ierr = VecNorm(Y,NORM_2,ynorm);CHKERRQ(ierr); 150 PetscFunctionReturn(0); 151 } 152 153 PETSC_EXTERN PetscErrorCode SNESLineSearchCreate_NCGLinear(SNESLineSearch linesearch) 154 { 155 PetscFunctionBegin; 156 linesearch->ops->apply = SNESLineSearchApply_NCGLinear; 157 linesearch->ops->destroy = NULL; 158 linesearch->ops->setfromoptions = NULL; 159 linesearch->ops->reset = NULL; 160 linesearch->ops->view = NULL; 161 linesearch->ops->setup = NULL; 162 PetscFunctionReturn(0); 163 } 164 165 /* 166 167 Assuming F = SNESComputeFunction(X) compute Y^tJ^tF using a simple secant approximation of the jacobian. 168 169 */ 170 PetscErrorCode SNESNCGComputeYtJtF_Private(SNES snes, Vec X, Vec F, Vec Y, Vec W, Vec G, PetscScalar * ytJtf) 171 { 172 PetscErrorCode ierr; 173 PetscScalar ftf, ftg, fty, h; 174 175 PetscFunctionBegin; 176 ierr = VecDot(F, F, &ftf);CHKERRQ(ierr); 177 ierr = VecDot(F, Y, &fty);CHKERRQ(ierr); 178 h = 1e-5*fty / fty; 179 ierr = VecCopy(X, W);CHKERRQ(ierr); 180 ierr = VecAXPY(W, -h, Y);CHKERRQ(ierr); /* this is arbitrary */ 181 ierr = SNESComputeFunction(snes, W, G);CHKERRQ(ierr); 182 ierr = VecDot(G, F, &ftg);CHKERRQ(ierr); 183 *ytJtf = (ftg - ftf) / h; 184 PetscFunctionReturn(0); 185 } 186 187 /*@ 188 SNESNCGSetType - Sets the conjugate update type for SNESNCG. 189 190 Logically Collective on SNES 191 192 Input Parameters: 193 + snes - the iterative context 194 - btype - update type 195 196 Options Database: 197 . -snes_ncg_type<prp,fr,hs,dy,cd> 198 199 Level: intermediate 200 201 SNESNCGSelectTypes: 202 + SNES_NCG_FR - Fletcher-Reeves update 203 . SNES_NCG_PRP - Polak-Ribiere-Polyak update 204 . SNES_NCG_HS - Hestenes-Steifel update 205 . SNES_NCG_DY - Dai-Yuan update 206 - SNES_NCG_CD - Conjugate Descent update 207 208 Notes: 209 PRP is the default, and the only one that tolerates generalized search directions. 210 211 .keywords: SNES, SNESNCG, selection, type, set 212 @*/ 213 PetscErrorCode SNESNCGSetType(SNES snes, SNESNCGType btype) 214 { 215 PetscErrorCode ierr; 216 217 PetscFunctionBegin; 218 PetscValidHeaderSpecific(snes,SNES_CLASSID,1); 219 ierr = PetscTryMethod(snes,"SNESNCGSetType_C",(SNES,SNESNCGType),(snes,btype));CHKERRQ(ierr); 220 PetscFunctionReturn(0); 221 } 222 223 PetscErrorCode SNESNCGSetType_NCG(SNES snes, SNESNCGType btype) 224 { 225 SNES_NCG *ncg = (SNES_NCG*)snes->data; 226 227 PetscFunctionBegin; 228 ncg->type = btype; 229 PetscFunctionReturn(0); 230 } 231 232 /* 233 SNESSolve_NCG - Solves a nonlinear system with the Nonlinear Conjugate Gradient method. 234 235 Input Parameters: 236 . snes - the SNES context 237 238 Output Parameter: 239 . outits - number of iterations until termination 240 241 Application Interface Routine: SNESSolve() 242 */ 243 PetscErrorCode SNESSolve_NCG(SNES snes) 244 { 245 SNES_NCG *ncg = (SNES_NCG*)snes->data; 246 Vec X,dX,lX,F,dXold; 247 PetscReal fnorm, ynorm, xnorm, beta = 0.0; 248 PetscScalar dXdotdX, dXolddotdXold, dXdotdXold, lXdotdX, lXdotdXold; 249 PetscInt maxits, i; 250 PetscErrorCode ierr; 251 SNESLineSearchReason lsresult = SNES_LINESEARCH_SUCCEEDED; 252 SNESLineSearch linesearch; 253 SNESConvergedReason reason; 254 255 PetscFunctionBegin; 256 if (snes->xl || snes->xu || snes->ops->computevariablebounds) SETERRQ1(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE, "SNES solver %s does not support bounds", ((PetscObject)snes)->type_name); 257 258 ierr = PetscCitationsRegister(SNESCitation,&SNEScite);CHKERRQ(ierr); 259 snes->reason = SNES_CONVERGED_ITERATING; 260 261 maxits = snes->max_its; /* maximum number of iterations */ 262 X = snes->vec_sol; /* X^n */ 263 dXold = snes->work[0]; /* The previous iterate of X */ 264 dX = snes->work[1]; /* the preconditioned direction */ 265 lX = snes->vec_sol_update; /* the conjugate direction */ 266 F = snes->vec_func; /* residual vector */ 267 268 ierr = SNESGetLineSearch(snes, &linesearch);CHKERRQ(ierr); 269 270 ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr); 271 snes->iter = 0; 272 snes->norm = 0.; 273 ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr); 274 275 /* compute the initial function and preconditioned update dX */ 276 277 if (snes->npc && snes->functype == SNES_FUNCTION_PRECONDITIONED) { 278 ierr = SNESApplyNPC(snes,X,NULL,dX);CHKERRQ(ierr); 279 ierr = SNESGetConvergedReason(snes->npc,&reason);CHKERRQ(ierr); 280 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 281 snes->reason = SNES_DIVERGED_INNER; 282 PetscFunctionReturn(0); 283 } 284 ierr = VecCopy(dX,F);CHKERRQ(ierr); 285 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 286 } else { 287 if (!snes->vec_func_init_set) { 288 ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr); 289 } else snes->vec_func_init_set = PETSC_FALSE; 290 291 /* convergence test */ 292 ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); 293 SNESCheckFunctionNorm(snes,fnorm); 294 ierr = VecCopy(F,dX);CHKERRQ(ierr); 295 } 296 if (snes->npc) { 297 if (snes->functype == SNES_FUNCTION_UNPRECONDITIONED) { 298 ierr = SNESApplyNPC(snes,X,F,dX);CHKERRQ(ierr); 299 ierr = SNESGetConvergedReason(snes->npc,&reason);CHKERRQ(ierr); 300 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 301 snes->reason = SNES_DIVERGED_INNER; 302 PetscFunctionReturn(0); 303 } 304 } 305 } 306 ierr = VecCopy(dX,lX);CHKERRQ(ierr); 307 ierr = VecDot(dX, dX, &dXdotdX);CHKERRQ(ierr); 308 309 310 ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr); 311 snes->norm = fnorm; 312 ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr); 313 ierr = SNESLogConvergenceHistory(snes,fnorm,0);CHKERRQ(ierr); 314 ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr); 315 316 /* test convergence */ 317 ierr = (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr); 318 if (snes->reason) PetscFunctionReturn(0); 319 320 /* Call general purpose update function */ 321 if (snes->ops->update) { 322 ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr); 323 } 324 325 /* first update -- just use the (preconditioned) residual direction for the initial conjugate direction */ 326 327 for (i = 1; i < maxits + 1; i++) { 328 /* some update types require the old update direction or conjugate direction */ 329 if (ncg->type != SNES_NCG_FR) { 330 ierr = VecCopy(dX, dXold);CHKERRQ(ierr); 331 } 332 ierr = SNESLineSearchApply(linesearch,X,F,&fnorm,lX);CHKERRQ(ierr); 333 ierr = SNESLineSearchGetReason(linesearch, &lsresult);CHKERRQ(ierr); 334 ierr = SNESLineSearchGetNorms(linesearch, &xnorm, &fnorm, &ynorm);CHKERRQ(ierr); 335 if (lsresult) { 336 if (++snes->numFailures >= snes->maxFailures) { 337 snes->reason = SNES_DIVERGED_LINE_SEARCH; 338 PetscFunctionReturn(0); 339 } 340 } 341 if (snes->nfuncs >= snes->max_funcs && snes->max_funcs >= 0) { 342 snes->reason = SNES_DIVERGED_FUNCTION_COUNT; 343 PetscFunctionReturn(0); 344 } 345 /* Monitor convergence */ 346 ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr); 347 snes->iter = i; 348 snes->norm = fnorm; 349 ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr); 350 ierr = SNESLogConvergenceHistory(snes,snes->norm,0);CHKERRQ(ierr); 351 ierr = SNESMonitor(snes,snes->iter,snes->norm);CHKERRQ(ierr); 352 353 /* Test for convergence */ 354 ierr = (*snes->ops->converged)(snes,snes->iter,xnorm,ynorm,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr); 355 if (snes->reason) PetscFunctionReturn(0); 356 357 /* Call general purpose update function */ 358 if (snes->ops->update) { 359 ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr); 360 } 361 if (snes->npc) { 362 if (snes->functype == SNES_FUNCTION_PRECONDITIONED) { 363 ierr = SNESApplyNPC(snes,X,NULL,dX);CHKERRQ(ierr); 364 ierr = SNESGetConvergedReason(snes->npc,&reason);CHKERRQ(ierr); 365 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 366 snes->reason = SNES_DIVERGED_INNER; 367 PetscFunctionReturn(0); 368 } 369 ierr = VecCopy(dX,F);CHKERRQ(ierr); 370 } else { 371 ierr = SNESApplyNPC(snes,X,F,dX);CHKERRQ(ierr); 372 ierr = SNESGetConvergedReason(snes->npc,&reason);CHKERRQ(ierr); 373 if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) { 374 snes->reason = SNES_DIVERGED_INNER; 375 PetscFunctionReturn(0); 376 } 377 } 378 } else { 379 ierr = VecCopy(F,dX);CHKERRQ(ierr); 380 } 381 382 /* compute the conjugate direction lX = dX + beta*lX with beta = ((dX, dX) / (dX_old, dX_old) (Fletcher-Reeves update)*/ 383 switch (ncg->type) { 384 case SNES_NCG_FR: /* Fletcher-Reeves */ 385 dXolddotdXold= dXdotdX; 386 ierr = VecDot(dX, dX, &dXdotdX);CHKERRQ(ierr); 387 beta = PetscRealPart(dXdotdX / dXolddotdXold); 388 break; 389 case SNES_NCG_PRP: /* Polak-Ribiere-Poylak */ 390 dXolddotdXold= dXdotdX; 391 ierr = VecDotBegin(dX, dX, &dXdotdXold);CHKERRQ(ierr); 392 ierr = VecDotBegin(dXold, dX, &dXdotdXold);CHKERRQ(ierr); 393 ierr = VecDotEnd(dX, dX, &dXdotdX);CHKERRQ(ierr); 394 ierr = VecDotEnd(dXold, dX, &dXdotdXold);CHKERRQ(ierr); 395 beta = PetscRealPart(((dXdotdX - dXdotdXold) / dXolddotdXold)); 396 if (beta < 0.0) beta = 0.0; /* restart */ 397 break; 398 case SNES_NCG_HS: /* Hestenes-Stiefel */ 399 ierr = VecDotBegin(dX, dX, &dXdotdX);CHKERRQ(ierr); 400 ierr = VecDotBegin(dX, dXold, &dXdotdXold);CHKERRQ(ierr); 401 ierr = VecDotBegin(lX, dX, &lXdotdX);CHKERRQ(ierr); 402 ierr = VecDotBegin(lX, dXold, &lXdotdXold);CHKERRQ(ierr); 403 ierr = VecDotEnd(dX, dX, &dXdotdX);CHKERRQ(ierr); 404 ierr = VecDotEnd(dX, dXold, &dXdotdXold);CHKERRQ(ierr); 405 ierr = VecDotEnd(lX, dX, &lXdotdX);CHKERRQ(ierr); 406 ierr = VecDotEnd(lX, dXold, &lXdotdXold);CHKERRQ(ierr); 407 beta = PetscRealPart((dXdotdX - dXdotdXold) / (lXdotdX - lXdotdXold)); 408 break; 409 case SNES_NCG_DY: /* Dai-Yuan */ 410 ierr = VecDotBegin(dX, dX, &dXdotdX);CHKERRQ(ierr); 411 ierr = VecDotBegin(lX, dX, &lXdotdX);CHKERRQ(ierr); 412 ierr = VecDotBegin(lX, dXold, &lXdotdXold);CHKERRQ(ierr); 413 ierr = VecDotEnd(dX, dX, &dXdotdX);CHKERRQ(ierr); 414 ierr = VecDotEnd(lX, dX, &lXdotdX);CHKERRQ(ierr); 415 ierr = VecDotEnd(lX, dXold, &lXdotdXold);CHKERRQ(ierr); 416 beta = PetscRealPart(dXdotdX / (lXdotdXold - lXdotdX));CHKERRQ(ierr); 417 break; 418 case SNES_NCG_CD: /* Conjugate Descent */ 419 ierr = VecDotBegin(dX, dX, &dXdotdX);CHKERRQ(ierr); 420 ierr = VecDotBegin(lX, dXold, &lXdotdXold);CHKERRQ(ierr); 421 ierr = VecDotEnd(dX, dX, &dXdotdX);CHKERRQ(ierr); 422 ierr = VecDotEnd(lX, dXold, &lXdotdXold);CHKERRQ(ierr); 423 beta = PetscRealPart(dXdotdX / lXdotdXold);CHKERRQ(ierr); 424 break; 425 } 426 if (ncg->monitor) { 427 ierr = PetscViewerASCIIPrintf(ncg->monitor, "beta = %e\n", (double)beta);CHKERRQ(ierr); 428 } 429 ierr = VecAYPX(lX, beta, dX);CHKERRQ(ierr); 430 } 431 ierr = PetscInfo1(snes, "Maximum number of iterations has been reached: %D\n", maxits);CHKERRQ(ierr); 432 if (!snes->reason) snes->reason = SNES_DIVERGED_MAX_IT; 433 PetscFunctionReturn(0); 434 } 435 436 437 438 /*MC 439 SNESNCG - Nonlinear Conjugate-Gradient method for the solution of general nonlinear systems. 440 441 Level: beginner 442 443 Options Database: 444 + -snes_ncg_type <fr, prp, dy, hs, cd> - Choice of conjugate-gradient update parameter, default is prp. 445 . -snes_linesearch_type <cp,l2,basic> - Line search type. 446 - -snes_ncg_monitor - Print relevant information about the ncg iteration. 447 448 Notes: 449 This solves the nonlinear system of equations F(x) = 0 using the nonlinear generalization of the conjugate 450 gradient method. This may be used with a nonlinear preconditioner used to pick the new search directions, but otherwise 451 chooses the initial search direction as F(x) for the initial guess x. 452 453 Only supports left non-linear preconditioning. 454 455 References: 456 . 1. - Peter R. Brune, Matthew G. Knepley, Barry F. Smith, and Xuemin Tu,"Composing Scalable Nonlinear Algebraic Solvers", 457 SIAM Review, 57(4), 2015 458 459 460 .seealso: SNESCreate(), SNES, SNESSetType(), SNESNEWTONLS, SNESNEWTONTR, SNESNGMRES, SNESQN 461 M*/ 462 PETSC_EXTERN PetscErrorCode SNESCreate_NCG(SNES snes) 463 { 464 PetscErrorCode ierr; 465 SNES_NCG * neP; 466 467 PetscFunctionBegin; 468 snes->ops->destroy = SNESDestroy_NCG; 469 snes->ops->setup = SNESSetUp_NCG; 470 snes->ops->setfromoptions = SNESSetFromOptions_NCG; 471 snes->ops->view = SNESView_NCG; 472 snes->ops->solve = SNESSolve_NCG; 473 snes->ops->reset = SNESReset_NCG; 474 475 snes->usesksp = PETSC_FALSE; 476 snes->usesnpc = PETSC_TRUE; 477 snes->npcside = PC_LEFT; 478 479 snes->alwayscomputesfinalresidual = PETSC_TRUE; 480 481 if (!snes->tolerancesset) { 482 snes->max_funcs = 30000; 483 snes->max_its = 10000; 484 snes->stol = 1e-20; 485 } 486 487 ierr = PetscNewLog(snes,&neP);CHKERRQ(ierr); 488 snes->data = (void*) neP; 489 neP->monitor = NULL; 490 neP->type = SNES_NCG_PRP; 491 ierr = PetscObjectComposeFunction((PetscObject)snes,"SNESNCGSetType_C", SNESNCGSetType_NCG);CHKERRQ(ierr); 492 PetscFunctionReturn(0); 493 } 494