Implements L-BFGS optimization algorithm for structural relaxation. More...

#include <lbfgs.h>

Collaboration diagram for LBFGS:

Public Member Functions
void	allocate (const int _size)
	Initialize L-BFGS parameters.

void	relax_step (const ModuleBase::matrix _force, UnitCell &ucell, const double &etot)
	Perform one L-BFGS relaxation step.

Private Member Functions
void	prepare_step (std::vector< std::vector< double > > &force, std::vector< std::vector< double > > &pos, std::vector< std::vector< double > > &H, std::vector< double > &pos0, std::vector< double > &force0, std::vector< std::vector< double > > &dpos, UnitCell &ucell, const double &etot)
	Prepare optimization step parameters.

void	is_restrain (std::vector< std::vector< double > > &dpos)
	Judge if the cell is restrain.

void	calculate_largest_grad (const ModuleBase::matrix &_force, UnitCell &ucell)
	Calculate maximum gradient component.

void	get_pos (UnitCell &ucell, std::vector< std::vector< double > > &pos)
	Extract atomic positions from unit cell.

void	get_pos_taud (UnitCell &ucell, std::vector< std::vector< double > > &pos_taud)
	Get fractional positions from unit cell.

void	update (std::vector< std::vector< double > > &pos_taud, std::vector< double > &pos_taud0, std::vector< double > &force, std::vector< double > &force0, UnitCell &ucell, int iteration, int memory, std::vector< std::vector< double > > &s, std::vector< std::vector< double > > &y, std::vector< double > &rho)
	Update L-BFGS history buffers.

void	determine_step (std::vector< double > &steplength, std::vector< std::vector< double > > &dpos, double &maxstep)
	Determine optimal step lengths.

void	update_pos (UnitCell &ucell)
	Update atomic positions in unit cell.

Private Attributes
double	alpha
	Initial Hessian diagonal element.

double	maxstep
	Maximum allowed step length.

int	size
	Number of atoms in system.

int	memory
	Number of previous steps to store.

double	H0
	Initial inverse Hessian approximation.

int	iteration
	Current iteration count.

double	energy
	Current system energy.

double	alpha_k
	Step size parameter.

ModuleESolver::ESolver *	solver
	Structure solver.

std::vector< std::vector< double > >	H
	Inverse Hessian approximation.

std::vector< double >	force0
	Previous step forces.

std::vector< std::vector< double > >	force
	Force history.

std::vector< double >	pos0
	Previous positions.

std::vector< std::vector< double > >	pos
	Position history.

std::vector< double >	pos_taud0
	Previous fractional positions.

std::vector< std::vector< double > >	pos_taud
	Fractional position history.

std::vector< std::vector< double > >	dpos
	Position displacements.

std::vector< std::vector< double > >	s
	Position difference vectors.

std::vector< std::vector< double > >	y
	Force difference vectors.

std::vector< double >	rho
	Scalar products for L-BFGS update.

std::vector< double >	steplength
	Step lengths for each atom.

Detailed Description

Implements L-BFGS optimization algorithm for structural relaxation.

Member Function Documentation

◆ allocate()

void LBFGS::allocate ( const int _size )

Initialize L-BFGS parameters.

Parameters

_size Number of atoms in system

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◆ calculate_largest_grad()

void LBFGS::calculate_largest_grad	(	const ModuleBase::matrix &	_force,
		UnitCell &	ucell
	)

private

Calculate maximum gradient component.

Parameters

_force	Current force matrix
ucell	Unit cell being optimized

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◆ determine_step()

void LBFGS::determine_step	(	std::vector< double > &	steplength,
		std::vector< std::vector< double > > &	dpos,
		double &	maxstep
	)

private

Determine optimal step lengths.

Parameters

steplength	Output step lengths
dpos	Position displacements
maxstep	Maximum allowed step length

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◆ get_pos()

void LBFGS::get_pos	(	UnitCell &	ucell,
		std::vector< std::vector< double > > &	pos
	)

private

Extract atomic positions from unit cell.

Parameters

ucell	Unit cell to read
pos	Output position vector

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◆ get_pos_taud()

void LBFGS::get_pos_taud	(	UnitCell &	ucell,
		std::vector< std::vector< double > > &	pos_taud
	)

private

Get fractional positions from unit cell.

Parameters

ucell	Unit cell to read
pos_taud	Output fractional positions

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◆ is_restrain()

void LBFGS::is_restrain ( std::vector< std::vector< double > > & dpos )

private

Judge if the cell is restrain.

Parameters

dpos	Position displacements to constrain

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◆ prepare_step()

void LBFGS::prepare_step	(	std::vector< std::vector< double > > &	force,
		std::vector< std::vector< double > > &	pos,
		std::vector< std::vector< double > > &	H,
		std::vector< double > &	pos0,
		std::vector< double > &	force0,
		std::vector< std::vector< double > > &	dpos,
		UnitCell &	ucell,
		const double &	etot
	)

private

Prepare optimization step parameters.

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◆ relax_step()

void LBFGS::relax_step	(	const ModuleBase::matrix	_force,
		UnitCell &	ucell,
		const double &	etot
	)

Perform one L-BFGS relaxation step.

Parameters

_force	Current force
ucell	Unit cell to optimize
etot	Current total energy
p_esolver	Structure solver

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◆ update()

void LBFGS::update	(	std::vector< std::vector< double > > &	pos_taud,
		std::vector< double > &	pos_taud0,
		std::vector< double > &	force,
		std::vector< double > &	force0,
		UnitCell &	ucell,
		int	iteration,
		int	memory,
		std::vector< std::vector< double > > &	s,
		std::vector< std::vector< double > > &	y,
		std::vector< double > &	rho
	)

private

Update L-BFGS history buffers.

Parameters

pos_taud	Current fractional positions
pos_taud0	Previous fractional positions
force	Current forces
force0	Previous forces
ucell	Unit cell being optimized
iteration	Current step number
memory	History buffer size
s	Position differences buffer
y	Force differences buffer
rho	Scalar products buffer

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◆ update_pos()

void LBFGS::update_pos ( UnitCell & ucell )

private

Update atomic positions in unit cell.

Parameters

ucell Unit cell to update

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Member Data Documentation

◆ alpha

double LBFGS::alpha

private

Initial Hessian diagonal element.

◆ alpha_k

double LBFGS::alpha_k

private

Step size parameter.

◆ dpos

std::vector<std::vector<double> > LBFGS::dpos

private

Position displacements.

◆ energy

double LBFGS::energy

private

Current system energy.

◆ force

std::vector<std::vector<double> > LBFGS::force

private

Force history.

◆ force0

std::vector<double> LBFGS::force0

private

Previous step forces.

◆ H

std::vector<std::vector<double> > LBFGS::H

private

Inverse Hessian approximation.

◆ H0

double LBFGS::H0

private

Initial inverse Hessian approximation.

◆ iteration

int LBFGS::iteration

private

Current iteration count.

◆ maxstep

double LBFGS::maxstep

private

Maximum allowed step length.

◆ memory

int LBFGS::memory

private

Number of previous steps to store.

◆ pos

std::vector<std::vector<double> > LBFGS::pos

private

Position history.

◆ pos0

std::vector<double> LBFGS::pos0

private

Previous positions.

◆ pos_taud

std::vector<std::vector<double> > LBFGS::pos_taud

private

Fractional position history.

◆ pos_taud0

std::vector<double> LBFGS::pos_taud0

private

Previous fractional positions.

◆ rho

std::vector<double> LBFGS::rho

private

Scalar products for L-BFGS update.

◆ s

std::vector<std::vector<double> > LBFGS::s

private

Position difference vectors.

◆ size

int LBFGS::size

private

Number of atoms in system.

◆ solver

ModuleESolver::ESolver* LBFGS::solver

private

Structure solver.

◆ steplength

std::vector<double> LBFGS::steplength

private

Step lengths for each atom.

◆ y

std::vector<std::vector<double> > LBFGS::y

private

Force difference vectors.

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

/home/runner/work/abacus-develop/abacus-develop/source/source_relax/lbfgs.h
/home/runner/work/abacus-develop/abacus-develop/source/source_relax/lbfgs.cpp

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Function Documentation

◆ allocate()

◆ calculate_largest_grad()

◆ determine_step()

◆ get_pos()

◆ get_pos_taud()

◆ is_restrain()

◆ prepare_step()

◆ relax_step()

◆ update()

◆ update_pos()

Member Data Documentation

◆ alpha

◆ alpha_k

◆ dpos

◆ energy

◆ force

◆ force0

◆ H

◆ H0

◆ iteration

◆ maxstep

◆ memory

◆ pos

◆ pos0

◆ pos_taud

◆ pos_taud0

◆ rho

◆ s

◆ size

◆ solver

◆ steplength

◆ y