edu.stanford.math.plex

Class SimplexStream

java.lang.Object

edu.stanford.math.plex.SimplexStream

All Implemented Interfaces:

java.lang.Iterable<Simplex>, java.util.Iterator<Simplex>

Direct Known Subclasses:

Cone, ExplicitStream, LazyWitnessStream, PointData.Discrete.DSS, RipsStream, SimplexStream.Stack, TmpStream, WitnessStream

public abstract class SimplexStream
extends java.lang.Object
implements java.lang.Iterable<Simplex>, java.util.Iterator<Simplex>

An instance of the abstract class SimplexStream provides the simplices of a filtered complex in lexicographic order on persistence index and dimension. The ordering is unspecified beyond that point, and may even vary from instance to instance. The reason that SimplexStream has both hasNext() and next() methods and implements the Iterable interface is that the internal iteration methods are allowed to be destructive. That is, it is possible (and in fact does happen) that stream.next() will remove simplices from stream, making it impossible to use this method to iterate over stream a second time. Therefore, unless you are prepared to consume the stream, use the Iterable interface.

Version:

$Id$

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SimplexStream.ComparisonType
static class	SimplexStream.Head A Head provides the FO part of a FIFO queue when attached to a Tail to which simplices have been enqueued.
static class	SimplexStream.Stack Stack is a multiway segmented stack for sorted storage of simplices.
static class	SimplexStream.Tail An instance of Tail provides the FI part of a FIFO queue.

Constructor Summary

Constructors

Constructor and Description
SimplexStream()

Method Summary

Methods

Modifier and Type	Method and Description
double	convert_filtration_index(int fi) Convert a filtration index into a persistence parameter (i.e., double) -- gets overloaded by some subclasses.
PersistenceBasisInterval.Float	convertInterval(PersistenceBasisInterval p) convert a PersistenceBasisInterval into Float format in a stream-specific manner.
PersistenceInterval.Float	convertInterval(PersistenceInterval p) Convert a PersistenceInterval into Float format in a stream-specific manner.
abstract boolean	hasNext() Is there a next Simplex in the stream?
abstract int	maxDimension() Max dimension of simplices in the stream.
abstract Simplex	next() Next Simplex in the stream.
void	remove() Unsupported remove() operation.
abstract int	size() How many simplices are in the stream?
boolean	verify() Check the stream as much as possible.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

iterator

Constructor Detail

SimplexStream

public SimplexStream()

Method Detail

hasNext

public abstract boolean hasNext()

Is there a next Simplex in the stream?

Specified by:

hasNext in interface java.util.Iterator<Simplex>

Returns:

Return true if the stream is not yet empty.

next

public abstract Simplex next()

Next Simplex in the stream.

Specified by:

next in interface java.util.Iterator<Simplex>

Returns:

Return the smallest remaining Simplex instance.

remove

public void remove()

Unsupported remove() operation.

Specified by:

remove in interface java.util.Iterator<Simplex>

Throws:

java.lang.UnsupportedOperationException

size

public abstract int size()

How many simplices are in the stream?

Returns:

The number of simplices in the stream.

maxDimension

public abstract int maxDimension()

Max dimension of simplices in the stream.

Returns:

Max dimension of simplices in the stream.

convertInterval

public PersistenceInterval.Float convertInterval(PersistenceInterval p)

Convert a PersistenceInterval into Float format in a stream-specific manner.

Parameters:

p - PersistenceInterval to convert.

Returns:

Converted PersistenceInterval.Float.

convertInterval

public PersistenceBasisInterval.Float convertInterval(PersistenceBasisInterval p)

convert a PersistenceBasisInterval into Float format in a stream-specific manner.

Parameters:

p - PersistenceBasisInterval to convert.

Returns:

Converted PersistenceBasisInterval.Float.

convert_filtration_index

public double convert_filtration_index(int fi)

Convert a filtration index into a persistence parameter (i.e., double) -- gets overloaded by some subclasses.

Parameters:

fi - Filtration index to convert.

Returns:

double persistence parameter.

verify

public boolean verify()

Check the stream as much as possible.

Returns:

True if the stream is consistent, else false.