xref: /petsc/src/tao/linesearch/impls/unit/unit.c (revision aaa7dc30da3270cff6cb10b1db605b2ca746f216)

#include <petscvec.h>
#include <taosolver.h>
#include <petsc-private/taolinesearchimpl.h>

#undef __FUNCT__
#define __FUNCT__ "TaoLineSearchDestroy_Unit"
static PetscErrorCode TaoLineSearchDestroy_Unit(TaoLineSearch ls)
{
  PetscErrorCode ierr;
  PetscFunctionBegin;
  ierr = PetscFree(ls->data);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "TaoLineSearchSetFromOptions_Unit"
static PetscErrorCode TaoLineSearchSetFromOptions_Unit(TaoLineSearch ls)
{
  PetscErrorCode ierr;
  PetscFunctionBegin;
  ierr = PetscOptionsHead("No Unit line search options");CHKERRQ(ierr);
  ierr = PetscOptionsTail();CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "TaoLineSearchView_Unit"
static PetscErrorCode TaoLineSearchView_Unit(TaoLineSearch ls,PetscViewer viewer)
{

  PetscErrorCode ierr;
  PetscBool isascii;
  PetscFunctionBegin;

  ierr = PetscObjectTypeCompare((PetscObject)viewer, PETSCVIEWERASCII, &isascii);CHKERRQ(ierr);
  if (isascii) {
      ierr=PetscViewerASCIIPrintf(viewer,"  Line Search: Unit Step.\n");CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "TaoLineSearchApply_Unit"
static PetscErrorCode TaoLineSearchApply_Unit(TaoLineSearch ls,Vec x,PetscReal *f,Vec g,Vec step_direction)
{
  PetscErrorCode   ierr;
  PetscReal ftry;
  PetscReal startf = *f;

  PetscFunctionBegin;

  /* Take unit step (newx = startx + 1.0*step_direction) */
  ierr = VecAXPY(x,1.0,step_direction);CHKERRQ(ierr);

  ierr = TaoLineSearchComputeObjectiveAndGradient(ls,x,&ftry,g);CHKERRQ(ierr);
  ierr = PetscInfo1(ls,"Tao Apply Unit Step: %4.4e\n",1.0);CHKERRQ(ierr);
  if (startf < ftry){
    ierr = PetscInfo2(ls,"Tao Apply Unit Step, FINCREASE: F old:= %12.10e, F new: %12.10e\n",startf,ftry);CHKERRQ(ierr);
  }
  *f = ftry;
  ls->step = 1.0;
  ls->reason=TAOLINESEARCH_SUCCESS;
  PetscFunctionReturn(0);
}

EXTERN_C_BEGIN
#undef __FUNCT__
#define __FUNCT__ "TaoLineSearchCreate_Unit"
/*@C
   TaoCreateUnitLineSearch - Always use step length of 1.0

   Input Parameters:
.  tao - TaoSolver context


   Level: advanced

.keywords: TaoSolver, linesearch
@*/
PetscErrorCode TaoLineSearchCreate_Unit(TaoLineSearch ls)
{

  PetscFunctionBegin;
  ls->ops->setup = 0;
  ls->ops->apply = TaoLineSearchApply_Unit;
  ls->ops->view = TaoLineSearchView_Unit;
  ls->ops->destroy = TaoLineSearchDestroy_Unit;
  ls->ops->setfromoptions = TaoLineSearchSetFromOptions_Unit;

  PetscFunctionReturn(0);
}
EXTERN_C_END