PetscErrorCode SNESSolve_NEWTONLS(SNES snes)
{
PetscErrorCode ierr;
PetscInt maxits,i,lits;
SNESLineSearchReason lssucceed;
PetscReal fnorm,gnorm,xnorm,ynorm;
Vec Y,X,F;
SNESLineSearch linesearch;
SNESConvergedReason reason;
PetscFunctionBegin;
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);
snes->numFailures = 0;
snes->numLinearSolveFailures = 0;
snes->reason = SNES_CONVERGED_ITERATING;
maxits = snes->max_its; /* maximum number of iterations */
X = snes->vec_sol; /* solution vector */
F = snes->vec_func; /* residual vector */
Y = snes->vec_sol_update; /* newton step */
ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr);
snes->iter = 0;
snes->norm = 0.0;
ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr);
ierr = SNESGetLineSearch(snes, &linesearch);CHKERRQ(ierr);
/* compute the preconditioned function first in the case of left preconditioning with preconditioned function */
if (snes->pc && snes->pcside == PC_LEFT && snes->functype == SNES_FUNCTION_PRECONDITIONED) {
ierr = SNESApplyNPC(snes,X,NULL,F);CHKERRQ(ierr);
ierr = SNESGetConvergedReason(snes->pc,&reason);CHKERRQ(ierr);
if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
snes->reason = SNES_DIVERGED_INNER;
PetscFunctionReturn(0);
}
ierr = VecNormBegin(F,NORM_2,&fnorm);CHKERRQ(ierr);
ierr = VecNormEnd(F,NORM_2,&fnorm);CHKERRQ(ierr);
} else {
if (!snes->vec_func_init_set) {
ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr);
} else snes->vec_func_init_set = PETSC_FALSE;
}
ierr = VecNorm(F,NORM_2,&fnorm);CHKERRQ(ierr); /* fnorm <- ||F|| */
SNESCheckFunctionNorm(snes,fnorm);
ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr);
snes->norm = fnorm;
ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr);
ierr = SNESLogConvergenceHistory(snes,fnorm,0);CHKERRQ(ierr);
ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr);
/* test convergence */
ierr = (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
if (snes->reason) PetscFunctionReturn(0);
for (i=0; i<maxits; i++) {
/* Call general purpose update function */
if (snes->ops->update) {
ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr);
}
/* apply the nonlinear preconditioner */
if (snes->pc) {
if (snes->pcside == PC_RIGHT) {
ierr = SNESSetInitialFunction(snes->pc, F);CHKERRQ(ierr);
ierr = PetscLogEventBegin(SNES_NPCSolve,snes->pc,X,snes->vec_rhs,0);CHKERRQ(ierr);
ierr = SNESSolve(snes->pc, snes->vec_rhs, X);CHKERRQ(ierr);
ierr = PetscLogEventEnd(SNES_NPCSolve,snes->pc,X,snes->vec_rhs,0);CHKERRQ(ierr);
ierr = SNESGetConvergedReason(snes->pc,&reason);CHKERRQ(ierr);
if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
snes->reason = SNES_DIVERGED_INNER;
PetscFunctionReturn(0);
}
ierr = SNESGetNPCFunction(snes,F,&fnorm);CHKERRQ(ierr);
} else if (snes->pcside == PC_LEFT && snes->functype == SNES_FUNCTION_UNPRECONDITIONED) {
ierr = SNESApplyNPC(snes,X,F,F);CHKERRQ(ierr);
ierr = SNESGetConvergedReason(snes->pc,&reason);CHKERRQ(ierr);
if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
snes->reason = SNES_DIVERGED_INNER;
PetscFunctionReturn(0);
}
}
}
/* Solve J Y = F, where J is Jacobian matrix */
ierr = SNESComputeJacobian(snes,X,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr);
ierr = KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr);
ierr = KSPSolve(snes->ksp,F,Y);CHKERRQ(ierr);
SNESCheckKSPSolve(snes);
ierr = KSPGetIterationNumber(snes->ksp,&lits);CHKERRQ(ierr);
snes->linear_its += lits;
ierr = PetscInfo2(snes,"iter=%D, linear solve iterations=%D\n",snes->iter,lits);CHKERRQ(ierr);
if (PetscLogPrintInfo) {
ierr = SNESNEWTONLSCheckResidual_Private(snes,snes->jacobian,F,Y);CHKERRQ(ierr);
}
/* Compute a (scaled) negative update in the line search routine:
X <- X - lambda*Y
and evaluate F = function(X) (depends on the line search).
*/
gnorm = fnorm;
ierr = SNESLineSearchApply(linesearch, X, F, &fnorm, Y);CHKERRQ(ierr);
ierr = SNESLineSearchGetReason(linesearch, &lssucceed);CHKERRQ(ierr);
ierr = SNESLineSearchGetNorms(linesearch, &xnorm, &fnorm, &ynorm);CHKERRQ(ierr);
ierr = PetscInfo4(snes,"fnorm=%18.16e, gnorm=%18.16e, ynorm=%18.16e, lssucceed=%d\n",(double)gnorm,(double)fnorm,(double)ynorm,(int)lssucceed);CHKERRQ(ierr);
if (snes->reason == SNES_DIVERGED_FUNCTION_COUNT) break;
SNESCheckFunctionNorm(snes,fnorm);
if (lssucceed) {
if (snes->stol*xnorm > ynorm) {
snes->reason = SNES_CONVERGED_SNORM_RELATIVE;
PetscFunctionReturn(0);
}
if (++snes->numFailures >= snes->maxFailures) {
PetscBool ismin;
snes->reason = SNES_DIVERGED_LINE_SEARCH;
ierr = SNESNEWTONLSCheckLocalMin_Private(snes,snes->jacobian,F,fnorm,&ismin);CHKERRQ(ierr);
if (ismin) snes->reason = SNES_DIVERGED_LOCAL_MIN;
break;
}
}
/* Monitor convergence */
ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr);
snes->iter = i+1;
snes->norm = fnorm;
ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr);
ierr = SNESLogConvergenceHistory(snes,snes->norm,lits);CHKERRQ(ierr);
ierr = SNESMonitor(snes,snes->iter,snes->norm);CHKERRQ(ierr);
/* Test for convergence */
ierr = (*snes->ops->converged)(snes,snes->iter,xnorm,ynorm,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
if (snes->reason) break;
}
if (i == maxits) {
ierr = PetscInfo1(snes,"Maximum number of iterations has been reached: %D\n",maxits);CHKERRQ(ierr);
if (!snes->reason) snes->reason = SNES_DIVERGED_MAX_IT;
}
PetscFunctionReturn(0);
}
PetscErrorCode SNESSolve_NEWTONLS(SNES snes)
{
PetscErrorCode ierr;
PetscInt maxits,i,lits;
PetscBool lssucceed;
MatStructure flg = DIFFERENT_NONZERO_PATTERN;
PetscReal fnorm,gnorm,xnorm,ynorm;
Vec Y,X,F,G,W,FPC;
KSPConvergedReason kspreason;
PetscBool domainerror;
SNESLineSearch linesearch;
SNESConvergedReason reason;
PetscFunctionBegin;
snes->numFailures = 0;
snes->numLinearSolveFailures = 0;
snes->reason = SNES_CONVERGED_ITERATING;
maxits = snes->max_its; /* maximum number of iterations */
X = snes->vec_sol; /* solution vector */
F = snes->vec_func; /* residual vector */
Y = snes->vec_sol_update; /* newton step */
G = snes->work[0];
W = snes->work[1];
ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
snes->iter = 0;
snes->norm = 0.0;
ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
ierr = SNESGetSNESLineSearch(snes, &linesearch);CHKERRQ(ierr);
if (!snes->vec_func_init_set) {
ierr = SNESComputeFunction(snes,X,F);CHKERRQ(ierr);
ierr = SNESGetFunctionDomainError(snes, &domainerror);CHKERRQ(ierr);
if (domainerror) {
snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
PetscFunctionReturn(0);
}
} else {
snes->vec_func_init_set = PETSC_FALSE;
}
if (!snes->norm_init_set) {
ierr = VecNormBegin(F,NORM_2,&fnorm);CHKERRQ(ierr); /* fnorm <- ||F|| */
ierr = VecNormEnd(F,NORM_2,&fnorm);CHKERRQ(ierr);
if (PetscIsInfOrNanReal(fnorm)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FP,"User provided compute function generated a Not-a-Number");
} else {
fnorm = snes->norm_init;
snes->norm_init_set = PETSC_FALSE;
}
ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
snes->norm = fnorm;
ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
SNESLogConvHistory(snes,fnorm,0);
ierr = SNESMonitor(snes,0,fnorm);CHKERRQ(ierr);
/* set parameter for default relative tolerance convergence test */
snes->ttol = fnorm*snes->rtol;
/* test convergence */
ierr = (*snes->ops->converged)(snes,0,0.0,0.0,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
if (snes->reason) PetscFunctionReturn(0);
for (i=0; i<maxits; i++) {
/* Call general purpose update function */
if (snes->ops->update) {
ierr = (*snes->ops->update)(snes, snes->iter);CHKERRQ(ierr);
}
/* apply the nonlinear preconditioner if it's right preconditioned */
if (snes->pc && snes->pcside == PC_RIGHT) {
ierr = SNESSetInitialFunction(snes->pc, F);CHKERRQ(ierr);
ierr = SNESSetInitialFunctionNorm(snes->pc, fnorm);CHKERRQ(ierr);
ierr = SNESSolve(snes->pc, snes->vec_rhs, X);CHKERRQ(ierr);
ierr = SNESGetConvergedReason(snes->pc,&reason);CHKERRQ(ierr);
if (reason < 0 && reason != SNES_DIVERGED_MAX_IT) {
snes->reason = SNES_DIVERGED_INNER;
PetscFunctionReturn(0);
}
ierr = SNESGetFunction(snes->pc, &FPC, PETSC_NULL, PETSC_NULL);CHKERRQ(ierr);
ierr = VecCopy(FPC, F);CHKERRQ(ierr);
ierr = SNESGetFunctionNorm(snes->pc, &fnorm);CHKERRQ(ierr);
}
/* Solve J Y = F, where J is Jacobian matrix */
ierr = SNESComputeJacobian(snes,X,&snes->jacobian,&snes->jacobian_pre,&flg);CHKERRQ(ierr);
ierr = KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre,flg);CHKERRQ(ierr);
ierr = SNES_KSPSolve(snes,snes->ksp,F,Y);CHKERRQ(ierr);
ierr = KSPGetConvergedReason(snes->ksp,&kspreason);CHKERRQ(ierr);
if (kspreason < 0) {
if (++snes->numLinearSolveFailures >= snes->maxLinearSolveFailures) {
ierr = PetscInfo2(snes,"iter=%D, number linear solve failures %D greater than current SNES allowed, stopping solve\n",snes->iter,snes->numLinearSolveFailures);CHKERRQ(ierr);
snes->reason = SNES_DIVERGED_LINEAR_SOLVE;
break;
}
}
ierr = KSPGetIterationNumber(snes->ksp,&lits);CHKERRQ(ierr);
snes->linear_its += lits;
ierr = PetscInfo2(snes,"iter=%D, linear solve iterations=%D\n",snes->iter,lits);CHKERRQ(ierr);
if (PetscLogPrintInfo){
ierr = SNESNEWTONLSCheckResidual_Private(snes,snes->jacobian,F,Y,G,W);CHKERRQ(ierr);
}
/* Compute a (scaled) negative update in the line search routine:
X <- X - lambda*Y
and evaluate F = function(X) (depends on the line search).
*/
gnorm = fnorm;
ierr = SNESLineSearchApply(linesearch, X, F, &fnorm, Y);CHKERRQ(ierr);
ierr = SNESLineSearchGetSuccess(linesearch, &lssucceed);CHKERRQ(ierr);
ierr = SNESLineSearchGetNorms(linesearch, &xnorm, &fnorm, &ynorm);CHKERRQ(ierr);
ierr = PetscInfo4(snes,"fnorm=%18.16e, gnorm=%18.16e, ynorm=%18.16e, lssucceed=%d\n",(double)gnorm,(double)fnorm,(double)ynorm,(int)lssucceed);CHKERRQ(ierr);
if (snes->reason == SNES_DIVERGED_FUNCTION_COUNT) break;
ierr = SNESGetFunctionDomainError(snes, &domainerror);CHKERRQ(ierr);
if (domainerror) {
snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN;
PetscFunctionReturn(0);
}
if (!lssucceed) {
if (snes->stol*xnorm > ynorm) {
snes->reason = SNES_CONVERGED_SNORM_RELATIVE;
PetscFunctionReturn(0);
}
if (++snes->numFailures >= snes->maxFailures) {
PetscBool ismin;
snes->reason = SNES_DIVERGED_LINE_SEARCH;
ierr = SNESNEWTONLSCheckLocalMin_Private(snes,snes->jacobian,F,W,fnorm,&ismin);CHKERRQ(ierr);
if (ismin) snes->reason = SNES_DIVERGED_LOCAL_MIN;
break;
}
}
/* Monitor convergence */
ierr = PetscObjectTakeAccess(snes);CHKERRQ(ierr);
snes->iter = i+1;
snes->norm = fnorm;
ierr = PetscObjectGrantAccess(snes);CHKERRQ(ierr);
SNESLogConvHistory(snes,snes->norm,lits);
ierr = SNESMonitor(snes,snes->iter,snes->norm);CHKERRQ(ierr);
/* Test for convergence */
ierr = (*snes->ops->converged)(snes,snes->iter,xnorm,ynorm,fnorm,&snes->reason,snes->cnvP);CHKERRQ(ierr);
if (snes->reason) break;
}
if (i == maxits) {
ierr = PetscInfo1(snes,"Maximum number of iterations has been reached: %D\n",maxits);CHKERRQ(ierr);
if (!snes->reason) snes->reason = SNES_DIVERGED_MAX_IT;
}
PetscFunctionReturn(0);
}