ShiftedLVMMMinimizer Class Reference
[Energy Minimizer]

Shifted limited-memory variable metric methods minimizer. More...

#include <shiftedLVMM.h>

Inheritance diagram for ShiftedLVMMMinimizer:


Public Types
Enums
enum	UpdateMethod { RANK_1 = 1, RANK_2 = 2 }
	The different variationally derived methods implemented. More...
enum	CorrectionParameter { UNIT_VALUE = 1, BALANCING_VALUE = 2, SQUARE_ROOT = 3, GEOMETRIC_MEAN = 4, RATIO_OF_SHIFT_PARAMS = 5 }
	The different correction parameters implemented. More...
Public Member Functions
Constructors and Destructors
	ShiftedLVMMMinimizer ()
	Default constructor.
	ShiftedLVMMMinimizer (ForceField &force_field)
	Constructor expecting a valid force field.
	ShiftedLVMMMinimizer (ForceField &force_field, SnapShotManager *ssm)
	Constructor expecting a valid force field and a snapshot manager.
	ShiftedLVMMMinimizer (ForceField &force_field, SnapShotManager *ssm, const Options &options)
	Constructor expecting a valid force field, a snapshot manager and options.
	ShiftedLVMMMinimizer (ForceField &force_field, const Options &options)
	Constructor expecting a valid force field and options.
	ShiftedLVMMMinimizer (const ShiftedLVMMMinimizer &rhs)
	Copy constructor.
virtual	~ShiftedLVMMMinimizer ()
	Destructor.
Assignments
const ShiftedLVMMMinimizer &	operator= (const ShiftedLVMMMinimizer &rhs)
	Assignment operator.
Setup methods. They do all necessary preparations.
virtual bool	specificSetup ()
	Specific setup.
Accessors
void	setUpdateMethod (UpdateMethod updt)
	Set explicitly the update method.
UpdateMethod	getUpdateMethod () const
	Return the update method.
void	setCorrectionParameter (CorrectionParameter corr)
	Set explicitly the correction parameter.
CorrectionParameter	getCorrectionParameter () const
	Return the correction parameter.
void	setMaxNumOfColumns (Size num)
	Set explicitly the maximum number of columns of the factor of the shifted inverse hessian approximation.
Size	getMaxNumOfColumns () const
	Return the maximum number of columns of the factor of the shifted inverse hessian approximation.
virtual double	findStep ()
	Calculate the next step.
virtual void	updateDirection ()
	Update the shifted inverse hessian approximation.
virtual bool	minimize (Size iterations=0, bool resume=false)
	Minimize the energy of the system.
Protected Attributes
Protected Attributes
LineSearch	line_search_
	The line search.
bool	first_iter_
	Is this an initial first iteration?
Size	number_of_atoms_
	Number of movable atoms.
Size	max_number_of_cols_
	Maximum number of columns of the factor of the shifted inverse hessian approximation.
Size	curr_number_of_cols_
	Current number of columns of the factor of the shifted inverse hessian approximation.
Size	updt_method_
	Update method.
Size	corr_par_
	Correction parameter.
double	prev_shift_val_
	Shift value of the previous iteration.
vector< Vector3 >	shift_s_
	Shifted previous step.
vector< Vector3 >	grad_diff_
	Current gradient difference.
vector< float >	updt_u_
	Needed vector for the update.
vector< float >	updt_v_
	Needed vector for the update.
vector< Vector3 >	shifted_direction_
	Direction of the shifted step, i. e. $-U_k \cdot U_k^T \cdot g_k$ .
vector< Vector3 >	hess_factor_
	Factor of the shifted inverse hessian approximation in column order, in [3].
vector< Vector3 >	initial_atoms_
	Positions of the movable atoms when we start an iteration.

Detailed Description

Shifted limited-memory variable metric methods minimizer.

A minimizer for geometry optimization based upon the shifted limited-memory variable metric methods proposed in

[1] Vlcek J., Luksan L.. New variable metric methods for unconstrained minimization covering the large-scale case. Report V-876, Prague, ICS AS CR, 2002.

[2] Vlcek J., Luksan L.. Additional properties of shifted variable metric methods. Report V-899, Prague, ICS AS CR, 2004.

[3] Vlcek J., Luksan L.. Shifted limited-memory variable metric methods for large-scale unconstrained optimization. Journal of Computational and Applied Mathematics 186 (2), pp. 365-390.

Member Enumeration Documentation

enum ShiftedLVMMMinimizer::CorrectionParameter

The different correction parameters implemented.

Enumeration values:

UNIT_VALUE Unit value, i.e.
rho = 1.0.

BALANCING_VALUE Balancing value.

SQUARE_ROOT Square root.

GEOMETRIC_MEAN Geometric mean.

RATIO_OF_SHIFT_PARAMS Ratio of shift parameters.

enum ShiftedLVMMMinimizer::UpdateMethod

The different variationally derived methods implemented.

Enumeration values:

RANK_1 Rank 1 variationally derived method.

RANK_2 Rank 2 variationally derived method.

Constructor & Destructor Documentation

ShiftedLVMMMinimizer::ShiftedLVMMMinimizer ( )

Default constructor.

virtual ShiftedLVMMMinimizer::~ShiftedLVMMMinimizer ( ) [virtual]

Destructor.

Member Function Documentation

virtual double ShiftedLVMMMinimizer::findStep ( ) [virtual]

Calculate the next step.
First, this method updates the model. Second, it performs a line search along the calculated direction afterwards.
Returns:
double $\geq 0$ if the line search found an acceptable solution, otherwise -1.

See also:
EnergyMinimizer::findStep

Reimplemented from EnergyMinimizer.

Size ShiftedLVMMMinimizer::getMaxNumOfColumns ( ) const

Return the maximum number of columns of the factor of the shifted inverse hessian approximation.

virtual bool ShiftedLVMMMinimizer::minimize ( Size iterations = 0,

bool resume = false

) [virtual]

Minimize the energy of the system.
This method executes at most iterations minimization steps. If the number of iterations is not given, the number specified in the options is taken.
Parameters:

iterations the maximum number of iterations

resume true to resume a previous run

See also:
EnergyMinimizer::minimize

Reimplemented from EnergyMinimizer.

void ShiftedLVMMMinimizer::setMaxNumOfColumns ( Size num )

Set explicitly the maximum number of columns of the factor of the shifted inverse hessian approximation.

virtual void ShiftedLVMMMinimizer::updateDirection ( ) [virtual]

Update the shifted inverse hessian approximation.
Afterwards, compute the search direction.
Reimplemented from EnergyMinimizer.

Member Data Documentation

Size ShiftedLVMMMinimizer::curr_number_of_cols_ [protected]

Current number of columns of the factor of the shifted inverse hessian approximation.

vector<Vector3> ShiftedLVMMMinimizer::grad_diff_ [protected]

Current gradient difference.

vector<Vector3> ShiftedLVMMMinimizer::hess_factor_ [protected]

Factor of the shifted inverse hessian approximation in column order, $U_k$ in [3].

vector<Vector3> ShiftedLVMMMinimizer::initial_atoms_ [protected]

Positions of the movable atoms when we start an iteration.
This is used to reduce slightly rounding errors

Size ShiftedLVMMMinimizer::max_number_of_cols_ [protected]

Maximum number of columns of the factor of the shifted inverse hessian approximation.

Size ShiftedLVMMMinimizer::number_of_atoms_ [protected]

Number of movable atoms.

double ShiftedLVMMMinimizer::prev_shift_val_ [protected]

Shift value of the previous iteration.

vector<Vector3> ShiftedLVMMMinimizer::shift_s_ [protected]

Shifted previous step.

vector<Vector3> ShiftedLVMMMinimizer::shifted_direction_ [protected]

Direction of the shifted step, i. e. $-U_k \cdot U_k^T \cdot g_k$ .

vector<float> ShiftedLVMMMinimizer::updt_u_ [protected]

Needed vector for the update.

vector<float> ShiftedLVMMMinimizer::updt_v_ [protected]

Needed vector for the update.

ShiftedLVMMMinimizer Class Reference [Energy Minimizer]

Public Types