tr.edu.bilkent.cs.partitioning.ccp

Class PrefixSumImpl

java.lang.Object

tr.edu.bilkent.cs.partitioning.ccp.PrefixSumImpl

All Implemented Interfaces:

PrefixSum

public class PrefixSumImpl
extends java.lang.Object
implements PrefixSum

A default PrefixSum implementation. Date: 14.08.2005

Constructor Summary

Constructors

Constructor and Description
PrefixSumImpl(double[] sum) The ctor.

Method Summary

Modifier and Type	Method and Description
double	get(int i) The sum of weights up to item i, i.e., t_0 + t_1 + ...
double[]	getArray() The underlying core prefix-summed array.
double	getAt(int p) returns the actual value of the item at p.
double[]	getOriginalValues() The actual values.
double	getSum() sum of all items.
double	getSum(int i, int j) Get a partial of the range (j, i], i.e.
int	search(double v) search for the prefix sum value.
int	searchGreaterThan(double v) returns the index of the smallest index that has a prefix sum not smaller than v.
int	searchLessThan(double v) returns the index of the largest index that has a prefix sum not larger than v.
int	size() The number of tasks.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

PrefixSumImpl

public PrefixSumImpl(double[] sum)

The ctor. Note that, the parameter is used without being cloned.

Parameters:

sum - the prefix-summed array.

Method Detail

size

public int size()

Description copied from interface: PrefixSum

The number of tasks.

Specified by:

size in interface PrefixSum

Returns:

number of tasks.

get

public double get(int i)

Description copied from interface: PrefixSum

The sum of weights up to item i, i.e., t_0 + t_1 + ... + t_i

Specified by:

get in interface PrefixSum

Parameters:

i - the last task for the summation.

Returns:

the sum.

getSum

public double getSum(int i,
                     int j)

Description copied from interface: PrefixSum

Get a partial of the range (j, i], i.e. \sum_{k=j+1}^i w_k.

Specified by:

getSum in interface PrefixSum

Parameters:

i - the index of the last weight to be summed.

j - the index of the task prior to the first task to be summed.

Returns:

sum of the range.

getSum

public double getSum()

Description copied from interface: PrefixSum

sum of all items.

Specified by:

getSum in interface PrefixSum

Returns:

total sum.

search

public int search(double v)

Description copied from interface: PrefixSum

search for the prefix sum value. returns the index of the nearest.

Specified by:

search in interface PrefixSum

Parameters:

v - the prefix sum value to be searched.

Returns:

nearest index.

searchLessThan

public int searchLessThan(double v)

Description copied from interface: PrefixSum

returns the index of the largest index that has a prefix sum not larger than v.

Specified by:

searchLessThan in interface PrefixSum

Parameters:

v - the prefix sum value to be searched.

Returns:

the index of the largest index that has a prefix sum not larger than v.

searchGreaterThan

public int searchGreaterThan(double v)

Description copied from interface: PrefixSum

returns the index of the smallest index that has a prefix sum not smaller than v.

Specified by:

searchGreaterThan in interface PrefixSum

Parameters:

v - the prefix sum value to be searched.

Returns:

the index of the smallest index that has a prefix sum not smaller than v.

getAt

public double getAt(int p)

Description copied from interface: PrefixSum

returns the actual value of the item at p.

Specified by:

getAt in interface PrefixSum

Parameters:

p - the index of the desired item.

Returns:

the actual value of the item at p.

getArray

public double[] getArray()

Description copied from interface: PrefixSum

The underlying core prefix-summed array. The implementations may return the internal structure for efficiency, thus, modifying this array is highly discouraged.

Specified by:

getArray in interface PrefixSum

Returns:

the internal prefix summed array.

getOriginalValues

public double[] getOriginalValues()

Description copied from interface: PrefixSum

The actual values. The implementations of this method are expected to calculate the original array. A new array is allocated and returned.

Specified by:

getOriginalValues in interface PrefixSum

Returns:

the original array.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object