/*@C SNESComputeObjective - Computes the objective. Collective on SNES Input Parameter: + snes - the SNES context - X - the state vector Output Parameter: . ob - the objective value Level: advanced .keywords: SNES, nonlinear, compute, objective .seealso: SNESSetObjective(), SNESGetSolution() @*/ PetscErrorCode SNESComputeObjective(SNES snes,Vec X,PetscReal *ob) { PetscErrorCode ierr; DM dm; DMSNES sdm; PetscFunctionBegin; PetscValidHeaderSpecific(snes,SNES_CLASSID,1); PetscValidHeaderSpecific(X,VEC_CLASSID,2); PetscValidPointer(ob,3); ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr); ierr = DMGetDMSNES(dm,&sdm);CHKERRQ(ierr); if (sdm->ops->computeobjective) { ierr = (sdm->ops->computeobjective)(snes,X,ob,sdm->objectivectx);CHKERRQ(ierr); } else SETERRQ(PetscObjectComm((PetscObject)snes),PETSC_ERR_ARG_WRONGSTATE, "Must call SNESSetObjective() before SNESComputeObjective()."); PetscFunctionReturn(0); }
/* SNESSolve_VINEWTONSSLS - Solves the complementarity problem with a semismooth Newton method using a line search. Input Parameters: . snes - the SNES context Application Interface Routine: SNESSolve() Notes: This implements essentially a semismooth Newton method with a line search. The default line search does not do any line search but rather takes a full Newton step. Developer Note: the code in this file should be slightly modified so that this routine need not exist and the SNESSolve_NEWTONLS() routine is called directly with the appropriate wrapped function and Jacobian evaluations */ PetscErrorCode SNESSolve_VINEWTONSSLS(SNES snes) { SNES_VINEWTONSSLS *vi = (SNES_VINEWTONSSLS*)snes->data; PetscErrorCode ierr; PetscInt maxits,i,lits; SNESLineSearchReason lssucceed; PetscReal gnorm,xnorm=0,ynorm; Vec Y,X,F; KSPConvergedReason kspreason; DM dm; DMSNES sdm; PetscFunctionBegin; ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr); ierr = DMGetDMSNES(dm,&sdm);CHKERRQ(ierr); vi->computeuserfunction = sdm->ops->computefunction; sdm->ops->computefunction = SNESVIComputeFunction; 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->work[0]; /* work vectors */ ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr); snes->iter = 0; snes->norm = 0.0; ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr); ierr = SNESVIProjectOntoBounds(snes,X);CHKERRQ(ierr); ierr = SNESComputeFunction(snes,X,vi->phi);CHKERRQ(ierr); if (snes->domainerror) { snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN; sdm->ops->computefunction = vi->computeuserfunction; PetscFunctionReturn(0); } /* Compute Merit function */ ierr = SNESVIComputeMeritFunction(vi->phi,&vi->merit,&vi->phinorm);CHKERRQ(ierr); ierr = VecNormBegin(X,NORM_2,&xnorm);CHKERRQ(ierr); /* xnorm <- ||x|| */ ierr = VecNormEnd(X,NORM_2,&xnorm);CHKERRQ(ierr); SNESCheckFunctionNorm(snes,vi->merit); ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr); snes->norm = vi->phinorm; ierr = PetscObjectSAWsGrantAccess((PetscObject)snes);CHKERRQ(ierr); ierr = SNESLogConvergenceHistory(snes,vi->phinorm,0);CHKERRQ(ierr); ierr = SNESMonitor(snes,0,vi->phinorm);CHKERRQ(ierr); /* test convergence */ ierr = (*snes->ops->converged)(snes,0,0.0,0.0,vi->phinorm,&snes->reason,snes->cnvP);CHKERRQ(ierr); if (snes->reason) { sdm->ops->computefunction = vi->computeuserfunction; 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); } /* Solve J Y = Phi, where J is the semismooth jacobian */ /* Get the jacobian -- note that the function must be the original function for snes_fd and snes_fd_color to work for this*/ sdm->ops->computefunction = vi->computeuserfunction; ierr = SNESComputeJacobian(snes,X,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); SNESCheckJacobianDomainerror(snes); sdm->ops->computefunction = SNESVIComputeFunction; /* Get the diagonal shift and row scaling vectors */ ierr = SNESVIComputeBsubdifferentialVectors(snes,X,F,snes->jacobian,vi->Da,vi->Db);CHKERRQ(ierr); /* Compute the semismooth jacobian */ ierr = SNESVIComputeJacobian(snes->jacobian,snes->jacobian_pre,vi->Da,vi->Db);CHKERRQ(ierr); /* Compute the merit function gradient */ ierr = SNESVIComputeMeritFunctionGradient(snes->jacobian,vi->phi,vi->dpsi);CHKERRQ(ierr); ierr = KSPSetOperators(snes->ksp,snes->jacobian,snes->jacobian_pre);CHKERRQ(ierr); ierr = KSPSolve(snes->ksp,vi->phi,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 (snes->ops->precheck) { PetscBool changed_y = PETSC_FALSE; ierr = (*snes->ops->precheck)(snes,X,Y,snes->precheck,&changed_y);CHKERRQ(ierr); } if (PetscLogPrintInfo) { ierr = SNESVICheckResidual_Private(snes,snes->jacobian,F,Y,G,W);CHKERRQ(ierr); } */ /* Compute a (scaled) negative update in the line search routine: Y <- X - lambda*Y and evaluate G = function(Y) (depends on the line search). */ ierr = VecCopy(Y,snes->vec_sol_update);CHKERRQ(ierr); ynorm = 1; gnorm = vi->phinorm; ierr = SNESLineSearchApply(snes->linesearch, X, vi->phi, &gnorm, Y);CHKERRQ(ierr); ierr = SNESLineSearchGetReason(snes->linesearch, &lssucceed);CHKERRQ(ierr); ierr = SNESLineSearchGetNorms(snes->linesearch, &xnorm, &gnorm, &ynorm);CHKERRQ(ierr); ierr = PetscInfo4(snes,"fnorm=%18.16e, gnorm=%18.16e, ynorm=%18.16e, lssucceed=%d\n",(double)vi->phinorm,(double)gnorm,(double)ynorm,(int)lssucceed);CHKERRQ(ierr); if (snes->reason == SNES_DIVERGED_FUNCTION_COUNT) break; if (snes->domainerror) { snes->reason = SNES_DIVERGED_FUNCTION_DOMAIN; sdm->ops->computefunction = vi->computeuserfunction; PetscFunctionReturn(0); } if (lssucceed) { if (++snes->numFailures >= snes->maxFailures) { PetscBool ismin; snes->reason = SNES_DIVERGED_LINE_SEARCH; ierr = SNESVICheckLocalMin_Private(snes,snes->jacobian,vi->phi,X,gnorm,&ismin);CHKERRQ(ierr); if (ismin) snes->reason = SNES_DIVERGED_LOCAL_MIN; break; } } /* Update function and solution vectors */ vi->phinorm = gnorm; vi->merit = 0.5*vi->phinorm*vi->phinorm; /* Monitor convergence */ ierr = PetscObjectSAWsTakeAccess((PetscObject)snes);CHKERRQ(ierr); snes->iter = i+1; snes->norm = vi->phinorm; snes->xnorm = xnorm; snes->ynorm = ynorm; 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, xnorm = || X || */ if (snes->ops->converged != SNESConvergedSkip) { ierr = VecNorm(X,NORM_2,&xnorm);CHKERRQ(ierr); } ierr = (*snes->ops->converged)(snes,snes->iter,xnorm,ynorm,vi->phinorm,&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; } sdm->ops->computefunction = vi->computeuserfunction; PetscFunctionReturn(0); }