Public Member Functions
	SQNM (int ndim_, int nhistx_, double alpha_)
	Construct a new SQNM::SQNM object using default parameters. More...

	SQNM (int ndim_, int nhistx_, double alpha_, double alpha0_, double eps_subsp_)
	Construct a new SQNM::SQNM object using custom parameters. More...

Eigen::VectorXd	step (Eigen::VectorXd &x, double &f_of_x, Eigen::VectorXd &df_dx)
	Calculates new coordinates that are closer to local minimum that the current coordinates. This function should be used the following way: More...

double	lower_bound ()
	Estimates a lower bound of the energy of the local minimum. More...

Private Member Functions
double	calc_gainratio (double &f)

void	adjust_stepsize (double &gainratio)

Eigen::MatrixXd	calc_ovrlp ()

Private Attributes
int	ndim

int	nhistx

double	eps_subsp = 1.e-3

double	alpha0 = 1.e-2

std::unique_ptr< hlist_space::HistoryList >	xlist

std::unique_ptr< hlist_space::HistoryList >	flist

double	alpha

Eigen::VectorXd	dir_of_descent

double	prev_f

Eigen::VectorXd	prev_df_dx

Eigen::VectorXd	expected_positions

Eigen::MatrixXd	h_subsp

Eigen::MatrixXd	h_evec_subsp

Eigen::MatrixXd	h_evec

Eigen::VectorXd	h_eval

Eigen::VectorXd	res

Eigen::SelfAdjointEigenSolver< Eigen::MatrixXd >	esolve

Eigen::VectorXd	res_temp

int	nhist = 0

bool	estimate_step_size = false

Detailed Description

Definition at line 20 of file sqnm.hpp.

Constructor & Destructor Documentation

◆ SQNM() [1/2]

vcsqnm::sqnm_space::SQNM::SQNM	(	int	ndim_,
		int	nhistx_,
		double	alpha_
	)

inline

Construct a new SQNM::SQNM object using default parameters.

Parameters

ndim_	number of dimensions of target function
nhistx_	Maximal number of steps that will be stored in the history list. Use a value between 3 and 20. Must be <= than ndim_.
alpha_	initial step size. default is 1.0. For systems with hard bonds (e.g. C-C) use a value between and 1.0 and 2.5 Should be approximately the inverse of the largest eigenvalue of the Hessian matrix. If alpha is negative, the inial step size is estimated using the mechanism from section 6.4 of the vc-sqnm paper: https://arxiv.org/abs/2206.07339 beta will then be equal to minus alpha. Good choices for beta are 0.1 in hartee / bohr^2 and 0.001 in eV / A^2

Definition at line 56 of file sqnm.hpp.

◆ SQNM() [2/2]

vcsqnm::sqnm_space::SQNM::SQNM	(	int	ndim_,
		int	nhistx_,
		double	alpha_,
		double	alpha0_,
		double	eps_subsp_
	)

inline

Construct a new SQNM::SQNM object using custom parameters.

Parameters

ndim_	number of dimensions of target function
nhistx_	Maximal number of steps that will be stored in the history list. Use a value between 3 and 20. Must be <= than ndim_.
alpha_	initial step size. default is 1.0. For systems with hard bonds (e.g. C-C) use a value between and 1.0 and 2.5. Should be approximately the inverse of the largest eigenvalue of the Hessian matrix. If alpha is negative, the inial step size is estimated using the mechanism from section 6.4 of the vc-sqnm paper: https://arxiv.org/abs/2206.07339 beta will then be equal to minus alpha. Good choices for beta are 0.1 in hartee / bohr^2 and 0.001 in eV / A^2
alpha0_	*
alpha0	Lower limit on the step size. 1.e-2 is the default.
eps_subsp_	Lower limit on linear dependencies of basis vectors in history list. Default 1.e-4.

Definition at line 86 of file sqnm.hpp.

Member Function Documentation

◆ step()

Eigen::VectorXd vcsqnm::sqnm_space::SQNM::step	(	Eigen::VectorXd &	x,
		double &	f_of_x,
		Eigen::VectorXd &	df_dx
	)

inline

Calculates new coordinates that are closer to local minimum that the current coordinates. This function should be used the following way:

calculate f(x) and the derivative.
call the step function.
add return value of step function to x.
repeat.

Parameters

x	Current position vector
f_of_x	value of the target function evaluated at position x.
df_dx	derivative of the target function evaluated at x.

Returns: VectorXd displacent that can be added to x in order to get new improved coordinates.

Definition at line 115 of file sqnm.hpp.

◆ lower_bound()

double vcsqnm::sqnm_space::SQNM::lower_bound ( )

inline

Estimates a lower bound of the energy of the local minimum.

Returns: double Lower bound estimate

Definition at line 245 of file sqnm.hpp.

◆ calc_gainratio()

double vcsqnm::sqnm_space::SQNM::calc_gainratio ( double & f )

inlineprivate

Definition at line 255 of file sqnm.hpp.

◆ adjust_stepsize()

void vcsqnm::sqnm_space::SQNM::adjust_stepsize ( double & gainratio )

inlineprivate

Definition at line 260 of file sqnm.hpp.

◆ calc_ovrlp()

Eigen::MatrixXd vcsqnm::sqnm_space::SQNM::calc_ovrlp ( )

inlineprivate

Definition at line 265 of file sqnm.hpp.

Member Data Documentation

◆ ndim

int vcsqnm::sqnm_space::SQNM::ndim

private

Definition at line 22 of file sqnm.hpp.

◆ nhistx

int vcsqnm::sqnm_space::SQNM::nhistx

private

Definition at line 23 of file sqnm.hpp.

◆ eps_subsp

double vcsqnm::sqnm_space::SQNM::eps_subsp = 1.e-3

private

Definition at line 24 of file sqnm.hpp.

◆ alpha0

double vcsqnm::sqnm_space::SQNM::alpha0 = 1.e-2

private

Definition at line 25 of file sqnm.hpp.

◆ xlist

std::unique_ptr<hlist_space::HistoryList> vcsqnm::sqnm_space::SQNM::xlist

private

Definition at line 26 of file sqnm.hpp.

◆ flist

std::unique_ptr<hlist_space::HistoryList> vcsqnm::sqnm_space::SQNM::flist

private

Definition at line 27 of file sqnm.hpp.

◆ alpha

double vcsqnm::sqnm_space::SQNM::alpha

private

Definition at line 28 of file sqnm.hpp.

◆ dir_of_descent

Eigen::VectorXd vcsqnm::sqnm_space::SQNM::dir_of_descent

private

Definition at line 29 of file sqnm.hpp.

◆ prev_f

double vcsqnm::sqnm_space::SQNM::prev_f

private

Definition at line 30 of file sqnm.hpp.

◆ prev_df_dx

Eigen::VectorXd vcsqnm::sqnm_space::SQNM::prev_df_dx

private

Definition at line 31 of file sqnm.hpp.

◆ expected_positions

Eigen::VectorXd vcsqnm::sqnm_space::SQNM::expected_positions

private

Definition at line 32 of file sqnm.hpp.

◆ h_subsp

Eigen::MatrixXd vcsqnm::sqnm_space::SQNM::h_subsp

private

Definition at line 33 of file sqnm.hpp.

◆ h_evec_subsp

Eigen::MatrixXd vcsqnm::sqnm_space::SQNM::h_evec_subsp

private

Definition at line 34 of file sqnm.hpp.

◆ h_evec

Eigen::MatrixXd vcsqnm::sqnm_space::SQNM::h_evec

private

Definition at line 35 of file sqnm.hpp.

◆ h_eval

Eigen::VectorXd vcsqnm::sqnm_space::SQNM::h_eval

private

Definition at line 36 of file sqnm.hpp.

◆ res

Eigen::VectorXd vcsqnm::sqnm_space::SQNM::res

private

Definition at line 37 of file sqnm.hpp.

◆ esolve

Eigen::SelfAdjointEigenSolver<Eigen::MatrixXd> vcsqnm::sqnm_space::SQNM::esolve

private

Definition at line 38 of file sqnm.hpp.

◆ res_temp

Eigen::VectorXd vcsqnm::sqnm_space::SQNM::res_temp

private

Definition at line 39 of file sqnm.hpp.

◆ nhist

int vcsqnm::sqnm_space::SQNM::nhist = 0

private

Definition at line 40 of file sqnm.hpp.

◆ estimate_step_size

bool vcsqnm::sqnm_space::SQNM::estimate_step_size = false

private

Definition at line 41 of file sqnm.hpp.

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

sqnm.hpp

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SQNM() [1/2]

◆ SQNM() [2/2]

Member Function Documentation

◆ step()

◆ lower_bound()

◆ calc_gainratio()

◆ adjust_stepsize()

◆ calc_ovrlp()

Member Data Documentation

◆ ndim

◆ nhistx

◆ eps_subsp

◆ alpha0

◆ xlist

◆ flist

◆ alpha

◆ dir_of_descent

◆ prev_f

◆ prev_df_dx

◆ expected_positions

◆ h_subsp

◆ h_evec_subsp

◆ h_evec

◆ h_eval

◆ res

◆ esolve

◆ res_temp

◆ nhist

◆ estimate_step_size