polyrun

Class PolytopeRunner

java.lang.Object

polyrun.PolytopeRunner

public class PolytopeRunner
extends Object

Represents runner that can generates samples from a polytope using any RandomWalk.

Constructor Summary

Constructors

Constructor and Description
PolytopeRunner(ConstraintsSystem constraintsSystem)
PolytopeRunner(ConstraintsSystem constraintsSystem, boolean removeRedundantConstraints, boolean skipZeroElements)
PolytopeRunner(ConstraintsSystem constraintsSystem, GLPSolver glpSolver, boolean skipZeroElements)
PolytopeRunner(ConstraintsSystem constraintsSystem, GLPSolver glpSolver, boolean skipZeroElements, double eps)

Method Summary

Modifier and Type	Method and Description
double[][]	chain(RandomWalk randomWalk, ThinningFunction thinningFunction, int numberOfSamples) Generates a chain of samples starting from startPoint.
void	chain(RandomWalk randomWalk, ThinningFunction thinningFunction, int numberOfSamples, SampleConsumer consumer) Generates a chain of samples starting from startPoint.
double[]	getStartPoint() Gets start point used as an initial point in methods chain and neighborhood.
double[][]	neighborhood(RandomWalk randomWalk, int numberOfSamples) Generates samples from the neighborhood of startPoint.
void	neighborhood(RandomWalk randomWalk, int numberOfSamples, SampleConsumer consumer) Generates samples from the neighborhood of startPoint.
void	setAnyStartPoint() Sets start point for methods chain and neighborhood.
void	setAnyStartPoint(GLPSolver glpSolver) Sets start point for methods chain and neighborhood.
void	setStartPoint(double[] startPoint) Sets start point for methods chain and neighborhood.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PolytopeRunner

public PolytopeRunner(ConstraintsSystem constraintsSystem)

Parameters:

constraintsSystem - system of constraints

PolytopeRunner

public PolytopeRunner(ConstraintsSystem constraintsSystem,
                      boolean removeRedundantConstraints,
                      boolean skipZeroElements)

Parameters:

constraintsSystem - system of constraints

removeRedundantConstraints - whether to remove redundant constraints (after initial transformation) or not; use for better performance if there may be some redundant constrains

skipZeroElements - whether RandomWalk should iterate over array of indices of non-zero elements or directly over entire transformed matrix A (from constraintsSystem)

PolytopeRunner

public PolytopeRunner(ConstraintsSystem constraintsSystem,
                      GLPSolver glpSolver,
                      boolean skipZeroElements)

Parameters:

constraintsSystem - system of constraints

glpSolver - solver; if not null redundant constrains will be removed; provide for better performance if there may be some redundant constrains

skipZeroElements - whether RandomWalk should iterate over array of indices of non-zero elements or directly over entire transformed matrix A (from constraintsSystem)

PolytopeRunner

public PolytopeRunner(ConstraintsSystem constraintsSystem,
                      GLPSolver glpSolver,
                      boolean skipZeroElements,
                      double eps)

Parameters:

constraintsSystem - system of constraints

glpSolver - solver; if not null redundant constrains will be removed; provide for better performance if there may be some redundant constrains

skipZeroElements - whether RandomWalk should iterate over array of indices of non-zero elements or directly over entire transformed matrix A (from constraintsSystem)

eps - absolute error to accept in floating point comparisons (non-negative, default 1e-10)

Method Detail

chain

public void chain(RandomWalk randomWalk,
                  ThinningFunction thinningFunction,
                  int numberOfSamples,
                  SampleConsumer consumer)

Generates a chain of samples starting from startPoint. The method uses startPoint for storing next steps and finally startPoint is set to the last sample from the chain - to be a start point in next call of chain or neighborhood.

Parameters:

randomWalk - sampler

thinningFunction - thinningFunction (see polyrun.thinning)

numberOfSamples - number of samples

consumer - samples consumer

neighborhood

public void neighborhood(RandomWalk randomWalk,
                         int numberOfSamples,
                         SampleConsumer consumer)

Generates samples from the neighborhood of startPoint. The method does not change startPoint.

Parameters:

randomWalk - sampler

numberOfSamples - number of samples

consumer - samples consumer

chain

public double[][] chain(RandomWalk randomWalk,
                        ThinningFunction thinningFunction,
                        int numberOfSamples)

Generates a chain of samples starting from startPoint. The method uses startPoint for storing next steps and finally it is set to the last sample from the chain to be a start point in next call of chain or neighborhood.

Parameters:

randomWalk - sampler

thinningFunction - thinning function (see polyrun.thinning)

numberOfSamples - number of samples

Returns:

array of generated samples

neighborhood

public double[][] neighborhood(RandomWalk randomWalk,
                               int numberOfSamples)

Generates samples from the neighborhood of startPoint. The method does not change startPoint.

Parameters:

randomWalk - sampler

numberOfSamples - number of samples

Returns:

array of generated samples

setAnyStartPoint

public void setAnyStartPoint()
                      throws UnboundedSystemException,
                             InfeasibleSystemException

Sets start point for methods chain and neighborhood. Set point is calculated by slack maximization between edges.

Throws:

UnboundedSystemException - if a polytope is tried to be built on top of unbounded system of constraints (in such a case polytope cannot be sampled)

InfeasibleSystemException - if a polytope is tried to be built on top of infeasible system of constraints (in such a case polytope cannot be sampled)

setAnyStartPoint

public void setAnyStartPoint(GLPSolver glpSolver)
                      throws UnboundedSystemException,
                             InfeasibleSystemException

Sets start point for methods chain and neighborhood. Set point is calculated by slack maximization between edges.

Parameters:

glpSolver - solver for General Linear Programing problem (e.g., CommonsMathGLPSolverWrapper)

Throws:

UnboundedSystemException - if a polytope is tried to be build on top of unbounded system of constraints (in such a case polytope cannot be sampled)

InfeasibleSystemException - if a polytope is tried to be build on top of infeasible system of constraints (in such a case polytope cannot be sampled)

setStartPoint

public void setStartPoint(double[] startPoint)

Sets start point for methods chain and neighborhood.

Parameters:

startPoint - point to be set

Throws:

IllegalArgumentException - if a startPoint is not an interior point of the polytope

getStartPoint

public double[] getStartPoint()

Gets start point used as an initial point in methods chain and neighborhood.

Returns:

start point