EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TaoCreate_OWLQN"
PetscErrorCode TaoCreate_OWLQN(Tao tao)
{
TAO_OWLQN *lmP;
const char *owarmijo_type = TAOLINESEARCHOWARMIJO;
PetscErrorCode ierr;
PetscFunctionBegin;
tao->ops->setup = TaoSetUp_OWLQN;
tao->ops->solve = TaoSolve_OWLQN;
tao->ops->view = TaoView_OWLQN;
tao->ops->setfromoptions = TaoSetFromOptions_OWLQN;
tao->ops->destroy = TaoDestroy_OWLQN;
ierr = PetscNewLog(tao,&lmP);CHKERRQ(ierr);
lmP->D = 0;
lmP->M = 0;
lmP->GV = 0;
lmP->Xold = 0;
lmP->Gold = 0;
lmP->lambda = 1.0;
tao->data = (void*)lmP;
tao->max_it = 2000;
tao->max_funcs = 4000;
tao->fatol = 1e-4;
tao->frtol = 1e-4;
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm,&tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch,owarmijo_type);CHKERRQ(ierr);
ierr = TaoLineSearchUseTaoRoutines(tao->linesearch,tao);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PETSC_EXTERN PetscErrorCode TaoCreate_BLMVM(Tao tao)
{
TAO_BLMVM *blmP;
const char *morethuente_type = TAOLINESEARCHMT;
PetscErrorCode ierr;
PetscFunctionBegin;
tao->ops->setup = TaoSetup_BLMVM;
tao->ops->solve = TaoSolve_BLMVM;
tao->ops->view = TaoView_BLMVM;
tao->ops->setfromoptions = TaoSetFromOptions_BLMVM;
tao->ops->destroy = TaoDestroy_BLMVM;
tao->ops->computedual = TaoComputeDual_BLMVM;
ierr = PetscNewLog(tao,&blmP);CHKERRQ(ierr);
blmP->H0 = NULL;
tao->data = (void*)blmP;
/* Override default settings (unless already changed) */
if (!tao->max_it_changed) tao->max_it = 2000;
if (!tao->max_funcs_changed) tao->max_funcs = 4000;
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm, &tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch, morethuente_type);CHKERRQ(ierr);
ierr = TaoLineSearchUseTaoRoutines(tao->linesearch,tao);CHKERRQ(ierr);
ierr = TaoLineSearchSetOptionsPrefix(tao->linesearch,tao->hdr.prefix);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TaoCreate_SQPCON"
PetscErrorCode TaoCreate_SQPCON(Tao tao)
{
TAO_SQPCON *sqpconP;
PetscErrorCode ierr;
const char *morethuente_type = TAOLINESEARCHMT;
PetscFunctionBegin;
tao->ops->setup = TaoSetup_SQPCON;
tao->ops->solve = TaoSolve_SQPCON;
tao->ops->view = TaoView_SQPCON;
tao->ops->setfromoptions = TaoSetFromOptions_SQPCON;
tao->ops->destroy = TaoDestroy_SQPCON;
ierr = PetscNewLog(tao,&sqpconP);CHKERRQ(ierr);
tao->data = (void*)sqpconP;
tao->max_it=200;
tao->fatol=1e-4;
tao->frtol=1e-4;
tao->gatol=1e-4;
tao->grtol=1e-4;
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm, &tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch, morethuente_type);CHKERRQ(ierr);
ierr = TaoLineSearchUseTaoRoutines(tao->linesearch,tao);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PETSC_EXTERN PetscErrorCode TaoCreate_GPCG(Tao tao)
{
TAO_GPCG *gpcg;
PetscErrorCode ierr;
PetscFunctionBegin;
tao->ops->setup = TaoSetup_GPCG;
tao->ops->solve = TaoSolve_GPCG;
tao->ops->view = TaoView_GPCG;
tao->ops->setfromoptions = TaoSetFromOptions_GPCG;
tao->ops->destroy = TaoDestroy_GPCG;
tao->ops->computedual = TaoComputeDual_GPCG;
ierr = PetscNewLog(tao,&gpcg);CHKERRQ(ierr);
tao->data = (void*)gpcg;
/* Override default settings (unless already changed) */
if (!tao->max_it_changed) tao->max_it=500;
if (!tao->max_funcs_changed) tao->max_funcs = 100000;
#if defined(PETSC_USE_REAL_SINGLE)
if (!tao->fatol_changed) tao->fatol=1e-6;
if (!tao->frtol_changed) tao->frtol=1e-6;
if (!tao->gatol_changed) tao->grtol=1e-6;
if (!tao->grtol_changed) tao->grtol=1e-6;
#else
if (!tao->fatol_changed) tao->fatol=1e-12;
if (!tao->frtol_changed) tao->frtol=1e-12;
if (!tao->gatol_changed) tao->grtol=1e-12;
if (!tao->grtol_changed) tao->grtol=1e-12;
#endif
/* Initialize pointers and variables */
gpcg->n=0;
gpcg->maxgpits = 8;
gpcg->pg_ftol = 0.1;
gpcg->gp_iterates=0; /* Cumulative number */
gpcg->total_gp_its = 0;
/* Initialize pointers and variables */
gpcg->n_bind=0;
gpcg->n_free = 0;
gpcg->n_upper=0;
gpcg->n_lower=0;
gpcg->subset_type = TAO_SUBSET_MASK;
gpcg->Hsub=NULL;
gpcg->Hsub_pre=NULL;
ierr = KSPCreate(((PetscObject)tao)->comm, &tao->ksp);CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(tao->ksp, tao->hdr.prefix);CHKERRQ(ierr);
ierr = KSPSetType(tao->ksp,KSPNASH);CHKERRQ(ierr);
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm, &tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch, TAOLINESEARCHGPCG);CHKERRQ(ierr);
ierr = TaoLineSearchSetObjectiveAndGradientRoutine(tao->linesearch, GPCGObjectiveAndGradient, tao);CHKERRQ(ierr);
ierr = TaoLineSearchSetOptionsPrefix(tao->linesearch,tao->hdr.prefix);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
/* ---------------------------------------------------------- */
EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TaoCreate_ASILS"
PetscErrorCode TaoCreate_ASILS(Tao tao)
{
TAO_SSLS *asls;
PetscErrorCode ierr;
const char *armijo_type = TAOLINESEARCHARMIJO;
PetscFunctionBegin;
ierr = PetscNewLog(tao,&asls);CHKERRQ(ierr);
tao->data = (void*)asls;
tao->ops->solve = TaoSolve_ASILS;
tao->ops->setup = TaoSetUp_ASILS;
tao->ops->view = TaoView_SSLS;
tao->ops->setfromoptions = TaoSetFromOptions_SSLS;
tao->ops->destroy = TaoDestroy_ASILS;
tao->subset_type = TAO_SUBSET_SUBVEC;
asls->delta = 1e-10;
asls->rho = 2.1;
asls->fixed = NULL;
asls->free = NULL;
asls->J_sub = NULL;
asls->Jpre_sub = NULL;
asls->w = NULL;
asls->r1 = NULL;
asls->r2 = NULL;
asls->r3 = NULL;
asls->t1 = NULL;
asls->t2 = NULL;
asls->dxfree = NULL;
asls->identifier = 1e-5;
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm, &tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch, armijo_type);CHKERRQ(ierr);
ierr = TaoLineSearchSetFromOptions(tao->linesearch);CHKERRQ(ierr);
ierr = KSPCreate(((PetscObject)tao)->comm, &tao->ksp);CHKERRQ(ierr);
ierr = KSPSetFromOptions(tao->ksp);CHKERRQ(ierr);
tao->max_it = 2000;
tao->max_funcs = 4000;
tao->fatol = 0;
tao->frtol = 0;
tao->gttol = 0;
tao->grtol = 0;
#if defined(PETSC_USE_REAL_SINGLE)
tao->gatol = 1.0e-6;
tao->fmin = 1.0e-4;
#else
tao->gatol = 1.0e-16;
tao->fmin = 1.0e-8;
#endif
PetscFunctionReturn(0);
}
/*MC
TAOGPCG - gradient projected conjugate gradient algorithm is an active-set
conjugate-gradient based method for bound-constrained minimization
Options Database Keys:
+ -tao_gpcg_maxpgits - maximum number of gradient projections for GPCG iterate
- -tao_subset_type - "subvec","mask","matrix-free", strategies for handling active-sets
Level: beginner
M*/
EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TaoCreate_GPCG"
PetscErrorCode TaoCreate_GPCG(Tao tao)
{
TAO_GPCG *gpcg;
PetscErrorCode ierr;
PetscFunctionBegin;
tao->ops->setup = TaoSetup_GPCG;
tao->ops->solve = TaoSolve_GPCG;
tao->ops->view = TaoView_GPCG;
tao->ops->setfromoptions = TaoSetFromOptions_GPCG;
tao->ops->destroy = TaoDestroy_GPCG;
tao->ops->computedual = TaoComputeDual_GPCG;
ierr = PetscNewLog(tao,&gpcg);CHKERRQ(ierr);
tao->data = (void*)gpcg;
tao->max_it = 500;
tao->max_funcs = 100000;
#if defined(PETSC_USE_REAL_SINGLE)
tao->fatol = 1e-6;
tao->frtol = 1e-6;
#else
tao->fatol = 1e-12;
tao->frtol = 1e-12;
#endif
/* Initialize pointers and variables */
gpcg->n=0;
gpcg->maxgpits = 8;
gpcg->pg_ftol = 0.1;
gpcg->gp_iterates=0; /* Cumulative number */
gpcg->total_gp_its = 0;
/* Initialize pointers and variables */
gpcg->n_bind=0;
gpcg->n_free = 0;
gpcg->n_upper=0;
gpcg->n_lower=0;
gpcg->subset_type = TAO_SUBSET_MASK;
/* gpcg->ksp_type = GPCG_KSP_STCG; */
ierr = KSPCreate(((PetscObject)tao)->comm, &tao->ksp);CHKERRQ(ierr);
ierr = KSPSetType(tao->ksp,KSPNASH);CHKERRQ(ierr);
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm, &tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch, TAOLINESEARCHGPCG);CHKERRQ(ierr);
ierr = TaoLineSearchSetObjectiveAndGradientRoutine(tao->linesearch, GPCGObjectiveAndGradient, tao);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
/*@
TaoLineSearchSetFromOptions - Sets various TaoLineSearch parameters from user
options.
Collective on TaoLineSearch
Input Paremeter:
. ls - the TaoLineSearch context
Options Database Keys:
+ -tao_ls_type <type> - The algorithm that TAO uses (more-thuente, gpcg, unit)
. -tao_ls_ftol <tol> - tolerance for sufficient decrease
. -tao_ls_gtol <tol> - tolerance for curvature condition
. -tao_ls_rtol <tol> - relative tolerance for acceptable step
. -tao_ls_stepmin <step> - minimum steplength allowed
. -tao_ls_stepmax <step> - maximum steplength allowed
. -tao_ls_max_funcs <n> - maximum number of function evaluations allowed
- -tao_ls_view - display line-search results to standard output
Level: beginner
@*/
PetscErrorCode TaoLineSearchSetFromOptions(TaoLineSearch ls)
{
PetscErrorCode ierr;
const char *default_type=TAOLINESEARCHMT;
char type[256];
PetscBool flg;
PetscFunctionBegin;
PetscValidHeaderSpecific(ls,TAOLINESEARCH_CLASSID,1);
ierr = PetscObjectOptionsBegin((PetscObject)ls);CHKERRQ(ierr);
if (!TaoLineSearchInitialized) {
ierr = TaoLineSearchInitializePackage();CHKERRQ(ierr);
}
if (((PetscObject)ls)->type_name) {
default_type = ((PetscObject)ls)->type_name;
}
/* Check for type from options */
ierr = PetscOptionsFList("-tao_ls_type","Tao Line Search type","TaoLineSearchSetType",TaoLineSearchList,default_type,type,256,&flg);CHKERRQ(ierr);
if (flg) {
ierr = TaoLineSearchSetType(ls,type);CHKERRQ(ierr);
} else if (!((PetscObject)ls)->type_name) {
ierr = TaoLineSearchSetType(ls,default_type);
}
ierr = PetscOptionsInt("-tao_ls_max_funcs","max function evals in line search","",ls->max_funcs,&ls->max_funcs,0);CHKERRQ(ierr);
ierr = PetscOptionsReal("-tao_ls_ftol","tol for sufficient decrease","",ls->ftol,&ls->ftol,0);CHKERRQ(ierr);
ierr = PetscOptionsReal("-tao_ls_gtol","tol for curvature condition","",ls->gtol,&ls->gtol,0);CHKERRQ(ierr);
ierr = PetscOptionsReal("-tao_ls_rtol","relative tol for acceptable step","",ls->rtol,&ls->rtol,0);CHKERRQ(ierr);
ierr = PetscOptionsReal("-tao_ls_stepmin","lower bound for step","",ls->stepmin,&ls->stepmin,0);CHKERRQ(ierr);
ierr = PetscOptionsReal("-tao_ls_stepmax","upper bound for step","",ls->stepmax,&ls->stepmax,0);CHKERRQ(ierr);
ierr = PetscOptionsBool("-tao_ls_view","view TaoLineSearch info after each line search has completed","TaoLineSearchView",PETSC_FALSE,&ls->viewls,NULL);CHKERRQ(ierr);
if (ls->ops->setfromoptions) {
ierr = (*ls->ops->setfromoptions)(ls);CHKERRQ(ierr);
}
ierr = PetscOptionsEnd();CHKERRQ(ierr);
PetscFunctionReturn(0);
}
EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TaoCreate_SSFLS"
PetscErrorCode TaoCreate_SSFLS(Tao tao)
{
TAO_SSLS *ssls;
PetscErrorCode ierr;
const char *armijo_type = TAOLINESEARCHARMIJO;
PetscFunctionBegin;
ierr = PetscNewLog(tao,&ssls);CHKERRQ(ierr);
tao->data = (void*)ssls;
tao->ops->solve=TaoSolve_SSFLS;
tao->ops->setup=TaoSetUp_SSFLS;
tao->ops->view=TaoView_SSLS;
tao->ops->setfromoptions=TaoSetFromOptions_SSLS;
tao->ops->destroy = TaoDestroy_SSFLS;
ssls->delta = 1e-10;
ssls->rho = 2.1;
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm,&tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch,armijo_type);CHKERRQ(ierr);
ierr = TaoLineSearchSetFromOptions(tao->linesearch);
/* Linesearch objective and objectivegradient routines are set in solve routine */
ierr = KSPCreate(((PetscObject)tao)->comm,&tao->ksp);CHKERRQ(ierr);
tao->max_it = 2000;
tao->max_funcs = 4000;
tao->fatol = 0;
tao->frtol = 0;
tao->grtol=0;
tao->grtol=0;
#if defined(PETSC_USE_REAL_SINGLE)
tao->gatol = 1.0e-6;
tao->fmin = 1.0e-4;
#else
tao->gatol = 1.0e-16;
tao->fmin = 1.0e-8;
#endif
PetscFunctionReturn(0);
}
PetscErrorCode TaoLineSearchSetUp(TaoLineSearch ls)
{
PetscErrorCode ierr;
const char *default_type=TAOLINESEARCHMT;
PetscBool flg;
PetscFunctionBegin;
PetscValidHeaderSpecific(ls,TAOLINESEARCH_CLASSID,1);
if (ls->setupcalled) PetscFunctionReturn(0);
if (!((PetscObject)ls)->type_name) {
ierr = TaoLineSearchSetType(ls,default_type);CHKERRQ(ierr);
}
if (ls->ops->setup) {
ierr = (*ls->ops->setup)(ls);CHKERRQ(ierr);
}
if (ls->usetaoroutines) {
ierr = TaoIsObjectiveDefined(ls->tao,&flg);CHKERRQ(ierr);
ls->hasobjective = flg;
ierr = TaoIsGradientDefined(ls->tao,&flg);CHKERRQ(ierr);
ls->hasgradient = flg;
ierr = TaoIsObjectiveAndGradientDefined(ls->tao,&flg);CHKERRQ(ierr);
ls->hasobjectiveandgradient = flg;
} else {
if (ls->ops->computeobjective) {
ls->hasobjective = PETSC_TRUE;
} else {
ls->hasobjective = PETSC_FALSE;
}
if (ls->ops->computegradient) {
ls->hasgradient = PETSC_TRUE;
} else {
ls->hasgradient = PETSC_FALSE;
}
if (ls->ops->computeobjectiveandgradient) {
ls->hasobjectiveandgradient = PETSC_TRUE;
} else {
ls->hasobjectiveandgradient = PETSC_FALSE;
}
}
ls->setupcalled = PETSC_TRUE;
PetscFunctionReturn(0);
}
PETSC_EXTERN PetscErrorCode TaoCreate_SSFLS(Tao tao)
{
TAO_SSLS *ssls;
PetscErrorCode ierr;
const char *armijo_type = TAOLINESEARCHARMIJO;
PetscFunctionBegin;
ierr = PetscNewLog(tao,&ssls);CHKERRQ(ierr);
tao->data = (void*)ssls;
tao->ops->solve=TaoSolve_SSFLS;
tao->ops->setup=TaoSetUp_SSFLS;
tao->ops->view=TaoView_SSLS;
tao->ops->setfromoptions = TaoSetFromOptions_SSLS;
tao->ops->destroy = TaoDestroy_SSFLS;
ssls->delta = 1e-10;
ssls->rho = 2.1;
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm,&tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch,armijo_type);CHKERRQ(ierr);
ierr = TaoLineSearchSetOptionsPrefix(tao->linesearch,tao->hdr.prefix);CHKERRQ(ierr);
ierr = TaoLineSearchSetFromOptions(tao->linesearch);CHKERRQ(ierr);
/* Linesearch objective and objectivegradient routines are set in solve routine */
ierr = KSPCreate(((PetscObject)tao)->comm,&tao->ksp);CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(tao->ksp,tao->hdr.prefix);CHKERRQ(ierr);
/* Override default settings (unless already changed) */
if (!tao->max_it_changed) tao->max_it = 2000;
if (!tao->max_funcs_changed) tao->max_funcs = 4000;
if (!tao->fatol_changed) tao->fatol = 0;
if (!tao->frtol_changed) tao->frtol = 0;
if (!tao->gttol_changed) tao->gttol = 0;
if (!tao->grtol_changed) tao->grtol = 0;
#if defined(PETSC_USE_REAL_SINGLE)
if (!tao->gatol_changed) tao->gatol = 1.0e-6;
if (!tao->fmin_changed) tao->fmin = 1.0e-4;
#else
if (!tao->gatol_changed) tao->gatol = 1.0e-16;
if (!tao->fmin_changed) tao->fmin = 1.0e-8;
#endif
PetscFunctionReturn(0);
}
PETSC_EXTERN PetscErrorCode TaoCreate_TRON(Tao tao)
{
TAO_TRON *tron;
PetscErrorCode ierr;
const char *morethuente_type = TAOLINESEARCHMT;
PetscFunctionBegin;
tao->ops->setup = TaoSetup_TRON;
tao->ops->solve = TaoSolve_TRON;
tao->ops->view = TaoView_TRON;
tao->ops->setfromoptions = TaoSetFromOptions_TRON;
tao->ops->destroy = TaoDestroy_TRON;
tao->ops->computedual = TaoComputeDual_TRON;
ierr = PetscNewLog(tao,&tron);CHKERRQ(ierr);
tao->data = (void*)tron;
/* Override default settings (unless already changed) */
if (!tao->max_it_changed) tao->max_it = 50;
#if defined(PETSC_USE_REAL_SINGLE)
if (!tao->steptol_changed) tao->steptol = 1.0e-6;
#else
if (!tao->steptol_changed) tao->steptol = 1.0e-12;
#endif
if (!tao->trust0_changed) tao->trust0 = 1.0;
/* Initialize pointers and variables */
tron->n = 0;
tron->maxgpits = 3;
tron->pg_ftol = 0.001;
tron->eta1 = 1.0e-4;
tron->eta2 = 0.25;
tron->eta3 = 0.50;
tron->eta4 = 0.90;
tron->sigma1 = 0.5;
tron->sigma2 = 2.0;
tron->sigma3 = 4.0;
tron->gp_iterates = 0; /* Cumulative number */
tron->total_gp_its = 0;
tron->n_free = 0;
tron->DXFree=NULL;
tron->R=NULL;
tron->X_New=NULL;
tron->G_New=NULL;
tron->Work=NULL;
tron->Free_Local=NULL;
tron->H_sub=NULL;
tron->Hpre_sub=NULL;
tao->subset_type = TAO_SUBSET_SUBVEC;
ierr = TaoLineSearchCreate(((PetscObject)tao)->comm, &tao->linesearch);CHKERRQ(ierr);
ierr = TaoLineSearchSetType(tao->linesearch,morethuente_type);CHKERRQ(ierr);
ierr = TaoLineSearchUseTaoRoutines(tao->linesearch,tao);CHKERRQ(ierr);
ierr = TaoLineSearchSetOptionsPrefix(tao->linesearch,tao->hdr.prefix);CHKERRQ(ierr);
ierr = KSPCreate(((PetscObject)tao)->comm, &tao->ksp);CHKERRQ(ierr);
ierr = KSPSetOptionsPrefix(tao->ksp, tao->hdr.prefix);CHKERRQ(ierr);
ierr = KSPSetType(tao->ksp,KSPSTCG);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
PetscObjectAllocateFortranPointers(*ls,NFUNCS);
if (!func) {
*ierr = TaoLineSearchSetObjectiveAndGTSRoutine(*ls,0,ctx);
} else {
((PetscObject)*ls)->fortran_func_pointers[OBJGTS] = (PetscVoidFunction)func;
*ierr = TaoLineSearchSetObjectiveAndGTSRoutine(*ls, ourtaolinesearchobjectiveandgtsroutine,ctx);
}
}
PETSC_EXTERN void PETSC_STDCALL taolinesearchsettype_(TaoLineSearch *ls, CHAR type_name PETSC_MIXED_LEN(len), PetscErrorCode *ierr PETSC_END_LEN(len))
{
char *t;
FIXCHAR(type_name,len,t);
*ierr = TaoLineSearchSetType(*ls,t);
FREECHAR(type_name,t);
}
PETSC_EXTERN void PETSC_STDCALL taolinesearchview_(TaoLineSearch *ls, PetscViewer *viewer, PetscErrorCode *ierr)
{
PetscViewer v;
PetscPatchDefaultViewers_Fortran(viewer,v);
*ierr = TaoLineSearchView(*ls,v);
}
PETSC_EXTERN void PETSC_STDCALL taolinesearchgetoptionsprefix_(TaoLineSearch *ls, CHAR prefix PETSC_MIXED_LEN(len), PetscErrorCode *ierr PETSC_END_LEN(len))
{
const char *name;
*ierr = TaoLineSearchGetOptionsPrefix(*ls,&name);
