ModuleBase::Opt_DCsrch Class Reference

A interface to line search. More...

#include <opt_DCsrch.h>

Collaboration diagram for ModuleBase::Opt_DCsrch:

Public Member Functions
	Opt_DCsrch ()
	~Opt_DCsrch ()
void	set_paras (double ftol=1e-4, double gtol=2e-1, double xtol=1e-12, double stpmin=0., double stpmax=ModuleBase::PI)
	Reset following parameters. The default setting in PROFESS is TN ftol = 1e-4 gtol = 2e-1 CG ftol = 1e-4 gtol = 1e-2 BFGS ftol = 1e-4 gtol = 2e-1.
void	dcSrch (double &f, double &g, double &rstp, char *rtask)
	Interface to dcsrch, finding the optimal step length with line search.

Private Attributes
double	ftol_ = 1e-4
double	gtol_ = 2e-1
double	xtol_ = 1e-12
double	stpmin_ = 0.
double	stpmax_ = ModuleBase::PI
int *	isave_ = nullptr
double *	dsave_ = nullptr

Detailed Description

A interface to line search.

Constructor & Destructor Documentation

Opt_DCsrch()

ModuleBase::Opt_DCsrch::Opt_DCsrch ( )

inline

~Opt_DCsrch()

ModuleBase::Opt_DCsrch::~Opt_DCsrch ( )

inline

Member Function Documentation

dcSrch()

void ModuleBase::Opt_DCsrch::dcSrch	(	double &	f,
		double &	g,
		double &	rstp,
		char *	rtask
	)

Interface to dcsrch, finding the optimal step length with line search.

Parameters

f	the value of the function at x on initial entry. On subsequent entries f is the value of the function at x + stp * d.
g	the derivative of the function at 0 on initial entry. On subsequent entries g is the derivative of the function at x + stp * d.
rstp	the optimized step length, assert the initial value is larger than zero.
rtask	a character variable of length at least 60. On initial entry task must be set to 'START'. On exit task indicates the required action: If task(1:2) = 'FG' then evaluate the function and derivative at stp and call dcsrch again. If task(1:4) = 'CONV' then the search is successful. If task(1:4) = 'WARN' then the subroutine is not able to satisfy the convergence conditions. The exit value of stp contains the best point found during the search. If task(1:5) = 'ERROR' then there is an error in the input arguments.

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set_paras()

void ModuleBase::Opt_DCsrch::set_paras ( double  ftol = 1e-4, double  gtol = 2e-1, double  xtol = 1e-12, double  stpmin = 0., double  stpmax = ModuleBase::PI  )

inline

Reset following parameters. The default setting in PROFESS is TN ftol = 1e-4 gtol = 2e-1 CG ftol = 1e-4 gtol = 1e-2 BFGS ftol = 1e-4 gtol = 2e-1.

Parameters

ftol	nonnegative tolerance for the sufficient decrease condition.
gtol	nonnegative tolerance for the curvature condition.
xtol	nonnegative relative tolerance for an acceptable step. The subroutine exits with a warning if the relative difference between sty and stx is less than xtol.
stpmin	nonnegative lower bound for the step.
stpmax	nonnegative upper bound for the step.

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Member Data Documentation

dsave_

double* ModuleBase::Opt_DCsrch::dsave_ = nullptr

private

ftol_

double ModuleBase::Opt_DCsrch::ftol_ = 1e-4

private

gtol_

double ModuleBase::Opt_DCsrch::gtol_ = 2e-1

private

isave_

int* ModuleBase::Opt_DCsrch::isave_ = nullptr

private

stpmax_

double ModuleBase::Opt_DCsrch::stpmax_ = ModuleBase::PI

private

stpmin_

double ModuleBase::Opt_DCsrch::stpmin_ = 0.

private

xtol_

double ModuleBase::Opt_DCsrch::xtol_ = 1e-12

private

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The documentation for this class was generated from the following files:

• /home/runner/work/abacus-develop/abacus-develop/source/source_base/opt_DCsrch.h
• /home/runner/work/abacus-develop/abacus-develop/source/source_base/opt_DCsrch.cpp