edu.stanford.math.plex

Class SimplexStream.Stack

java.lang.Object

edu.stanford.math.plex.SimplexStream

edu.stanford.math.plex.SimplexStream.Stack

All Implemented Interfaces:

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

Enclosing class:

SimplexStream

public static class SimplexStream.Stack
extends SimplexStream

Stack is a multiway segmented stack for sorted storage of simplices.

The class SimplexStream.Stack provides a simple, fast, scalable implementation of SimplexStream. Instances are arrays of segmented stacks of simplices, simplices are less than, equivalent, or greater than one another (for the purposes of the Persistence computations) if and only if the corresponding indices for their segmented stacks are <, ==, or >. In addition, the next() method drops references to the segments as soon as possible, which means that the stack consumes progressively less memory as its contents are processed.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	SimplexStream.Stack.Segment
protected static class	SimplexStream.Stack.StackIterator Instances provide Iterator for non-destructive iterating over Stack entries.

Nested classes/interfaces inherited from class edu.stanford.math.plex.SimplexStream

SimplexStream.ComparisonType, SimplexStream.Head, SimplexStream.Stack, SimplexStream.Tail

Field Summary

Fields

Modifier and Type	Field and Description
protected int	dimension_bound
protected int	findex_bound
protected int	segment_length
protected SimplexStream.Stack.Segment[]	segments
protected int	segments_index
protected int	simplex_index
protected int	size
protected static int	STACK_SEGMENT_LENGTH

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SimplexStream.Stack()
	SimplexStream.Stack(int max_findex, int max_d) Constructor for Stack.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	hasNext() Is there a next Simplex in the stream?
java.util.Iterator<Simplex>	iterator() Make a non-destructive iterator for the Stack.
java.util.Iterator<Simplex>	iterator(int d) Make a non-destructive iterator for fixed dimensional entries in the Stack.
int	maxDimension() Max dimension of simplices in the stream.
Simplex	next() Return the next Simplex in the stream.
Simplex	push(Simplex s) Push a Simplex into the stream.
protected int	simplexIndex(Simplex s)
int	size() How many simplices are in the stream?
java.lang.String	toString()

Methods inherited from class edu.stanford.math.plex.SimplexStream

convert_filtration_index, convertInterval, convertInterval, remove, verify

Methods inherited from class java.lang.Object

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

Field Detail

STACK_SEGMENT_LENGTH

protected static int STACK_SEGMENT_LENGTH

segments

protected final SimplexStream.Stack.Segment[] segments

findex_bound

protected final int findex_bound

dimension_bound

protected final int dimension_bound

segment_length

protected final int segment_length

size

protected int size

segments_index

protected int segments_index

simplex_index

protected int simplex_index

Constructor Detail

SimplexStream.Stack

protected SimplexStream.Stack()

SimplexStream.Stack

public SimplexStream.Stack(int max_findex,
                   int max_d)

Constructor for Stack.

Make a multi-way stack that automatically sorts simplices.

Parameters:

max_findex - Maximum Filtration Index we'll use.

max_d - Maximum dimension of a Simplex to be pushed.

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

simplexIndex

protected int simplexIndex(Simplex s)

push

public Simplex push(Simplex s)

Push a Simplex into the stream.

Add the Simplex s to the stream so that it will be retrieved in the proper order.

Parameters:

s - Simplex instance to push.

Returns:

s

size

public int size()

How many simplices are in the stream?

Specified by:

size in class SimplexStream

Returns:

The number of simplices in the stream.

maxDimension

public int maxDimension()

Max dimension of simplices in the stream.

Specified by:

maxDimension in class SimplexStream

Returns:

Max dimension of simplices in the stream.

hasNext

public boolean hasNext()

Is there a next Simplex in the stream?

Specified by:

hasNext in interface java.util.Iterator<Simplex>

Specified by:

hasNext in class SimplexStream

Returns:

Return true if the stream is not yet empty.

next

public Simplex next()

Return the next Simplex in the stream. This operations removes the simplex returned from the stream, so repeated iterations are impossible with the method.

Specified by:

next in interface java.util.Iterator<Simplex>

Specified by:

next in class SimplexStream

Returns:

The smallest remaining Simplex instance.

iterator

public java.util.Iterator<Simplex> iterator()

Make a non-destructive iterator for the Stack.

Returns:

Iterator instance for the stack.

See Also:

Iterator

iterator

public java.util.Iterator<Simplex> iterator(int d)

Make a non-destructive iterator for fixed dimensional entries in the Stack.

Parameters:

d - dimension of entries we want to iterate over

Returns:

Iterator instance for the stack.

See Also:

Iterator