smile.sort

Class DoubleHeapSelect

java.lang.Object

smile.sort.DoubleHeapSelect

public class DoubleHeapSelect
extends Object

This class tracks the smallest values seen thus far in a stream of values. This implements a single-pass selection for large data sets. That is, we have a stream of input values, each of which we get to see only once. We want to be able to report at any time, say after n values, the i-th smallest value see so far.

Author:

Haifeng Li

Constructor Summary

Constructors

Constructor and Description
DoubleHeapSelect(double[] heap) Constructor.
DoubleHeapSelect(int k) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	add(double datum) Assimilate a new value from the stream.
double	get(int i) Returns the i-th smallest value seen so far.
double	peek() Returns the k-th smallest value seen so far.
void	sort() Sort the smallest values.

Methods inherited from class java.lang.Object

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

Constructor Detail

DoubleHeapSelect

public DoubleHeapSelect(int k)

Constructor.

Parameters:

k - the heap size.

DoubleHeapSelect

public DoubleHeapSelect(double[] heap)

Constructor.

Parameters:

heap - the array to store smallest values to track.

Method Detail

add

public void add(double datum)

Assimilate a new value from the stream.

peek

public double peek()

Returns the k-th smallest value seen so far.

get

public double get(int i)

Returns the i-th smallest value seen so far. i = 0 returns the smallest value seen, i = 1 the second largest, ..., i = k-1 the last position tracked. Also, i must be less than the number of previous assimilated.

sort

public void sort()

Sort the smallest values.