import PreferredDirectionConstraint from 'Artistoo/src/hamiltonian/PreferredDirectionConstraint.js'
public class

PreferredDirectionConstraint

Extends:

ConstraintSoftConstraint → PreferredDirectionConstraint

Implements a global bias direction of motion. This constraint computes the unnormalized dot product between copy attempt vector and target direction vector.

Supply the target direction vector in normalized form, or use the length of the vector to influence the strength of this bias.

Works for torus grids, if they are "big enough".

Example:

// Build a CPM and add the constraint
let CPM = require( "path/to/build" )
let C = new CPM.CPM( [200,200], { T : 20 } )
LAMBDA_DIR : [0,50],
DIR : [[0,0],[1,1]]
} ) )

Constructor Summary

 Public Constructor public constructor(conf: object) The constructor of the PreferredDirectionConstraint requires a conf object with parameters.

Method Summary

 Public Methods public This method checks that all required parameters are present in the object supplied to the constructor, and that they are of the right format. public deltaH(src_i: IndexCoordinate, tgt_i: IndexCoordinate, src_type: CellId, tgt_type: CellId): number Method to compute the Hamiltonian for this constraint.

Inherited Summary

 From class Constraint public get abstract This method is actually implemented in the subclass. public set CPM(C: CPM) This function attaches the relevant CPM to this constraint, so that information about this cpm can be requested from the constraint. public get parameters: object: * Get the parameters of this constraint from the conf object. public C: CPM CPM on which this constraint acts. public Configuration object for this constraint. public abstract cellParameter(param: string, cid: CellId): any Get a cellid or cellkind-specific parameter for a constraint. public abstract The optional confChecker method should verify that all the required conf parameters are actually present in the conf object and have the right format. public paramOfCell(param: string, cid: CellId): any Get a cellId specific parameter, only used if CPMEvol is used: looks whether the requested parameter is overwritten in an @object Cell and otherwise returns @function paramOfKind public paramOfKind(param: string, cid: CellId): any Returns a cellKind specfic variable: Assumes that the parameter is indexable by cellkind.
 From class SoftConstraint public get Let the CPM know that this is a soft constraint, so return 'soft'. public abstract deltaH(src_i: IndexCoordinate, tgt_i: IndexCoordinate, src_type: CellId, tgt_type: CellId): number Soft constraints must have a deltaH method to compute the Hamiltonian.

Public Constructors

publicconstructor(conf: object) source

The constructor of the PreferredDirectionConstraint requires a conf object with parameters.

Override:

Constraint#constructor

Params:

 Name Type Attribute Description conf object parameter object for this constraint conf.LAMBDA_DIR PerKindNonNegative strength of the constraint per cellkind. conf.DIR 'vector' with the preferred direction. This is an array with the ArrayCoordinates of the start and endpoints of this vector.

Public Methods

publicconfChecker() source

This method checks that all required parameters are present in the object supplied to the constructor, and that they are of the right format. It throws an error when this is not the case.

Override:

Constraint#confChecker

publicdeltaH(src_i: IndexCoordinate, tgt_i: IndexCoordinate, src_type: CellId, tgt_type: CellId): number source

Method to compute the Hamiltonian for this constraint.

Override:

SoftConstraint#deltaH

Params:

 Name Type Attribute Description src_i IndexCoordinate coordinate of the source pixel that tries to copy. tgt_i IndexCoordinate coordinate of the target pixel the source is trying to copy into. src_type CellId cellid of the source pixel. tgt_type CellId cellid of the target pixel. This argument is not actually used but is given for consistency with other soft constraints; the CPM always calls this method with four arguments.

Return:

 number the change in Hamiltonian for this copy attempt and this constraint.