tr.edu.bilkent.cs.partitioning.ccp

Class Utils

java.lang.Object

tr.edu.bilkent.cs.partitioning.ccp.Utils

public class Utils
extends java.lang.Object

Several utility and factory methods. Date: 22.09.2005

Method Summary

Modifier and Type	Method and Description
static void	fullGc() performs a full garbage collection.
static double	getMax(PrefixSum pSum) max item of the prefix summed array.
static double	getMin(PrefixSum pSum) min item of the prefix summed array.
static PrefixSum	getRandomOrdering(PrefixSum origPSum, int seed) returns a prefix-summed random ordering of the given prefix summed chain.
static PrefixSum	getRandomProcessors(int p) The default random processor chain factory.
static PrefixSum	getRandomProcessors(int p, int seed, int range) Returns random processors.
static PrefixSum	getRandomProcessorsDouble(int p, int seed, int range) Returns random processors.
static PrefixSum	getRandomProcessorsNormal(int p, int seed, double mean, double deviation) Returns random processors.
static PrefixSum	getRandomProcessorsNormalSquare(int p, int seed, double mean, double deviation) Returns random processors.
static PrefixSum	getRandomProcessorsOrdered(int p, int seed, int range) Returns random processors.
static RunningStatistics	getStatistics(PrefixSum sequence) calculates and returns the statistics based on the sequence.
static PrefixSum	getUniformProcessors(int p) Returns a prefix summed processor speed array, with all processor speeds are 1.
static PrefixSum	prefixSum(double[] array) calculates the prefix sum of the array.
static PrefixSum	prefixSum(double[] array, boolean clone) calculates the prefix sum of the array.
static double[]	readArray(java.lang.String fileName) Reads the contents of the task array from a w-formatted file.

Methods inherited from class java.lang.Object

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

Method Detail

prefixSum

public static PrefixSum prefixSum(double[] array)

calculates the prefix sum of the array. The array is cloned for prefix sum.

Parameters:

array - the core array.

Returns:

the prefix sum of the array.

prefixSum

public static PrefixSum prefixSum(double[] array,
                                  boolean clone)

calculates the prefix sum of the array.

Parameters:

array - the core array.

clone - whether the array should be cloned, or the array can be used for the prefix sum.

Returns:

the prefix sum of the array.

readArray

public static double[] readArray(java.lang.String fileName)
                          throws java.io.IOException

Reads the contents of the task array from a w-formatted file. A w-formatted file is simply a text file: first line is an integer representing the number of tasks (n) and the next n lines hold n doubles as the weights of the tasks.

Parameters:

fileName - the filename to be read.

Returns:

the task array.

Throws:

java.io.IOException - if some exception occurs while reading.

getUniformProcessors

public static PrefixSum getUniformProcessors(int p)

Returns a prefix summed processor speed array, with all processor speeds are 1.

Parameters:

p - the number of processors.

Returns:

the prefix summed processor speed array.

getRandomProcessors

public static PrefixSum getRandomProcessors(int p,
                                            int seed,
                                            int range)

Returns random processors. The chosen processor indices are uniformly distributed integers in the range [1, range].

Parameters:

p - the number of processors.

seed - the seed.

range - the range.

Returns:

prefix summed processor speed array.

getRandomProcessorsOrdered

public static PrefixSum getRandomProcessorsOrdered(int p,
                                                   int seed,
                                                   int range)

Returns random processors. The chosen processor indices are uniformly distributed integers in the range [1, range]. Then the processors are sorted in increasing order.

Parameters:

p - the number of processors.

seed - the seed.

range - the range.

Returns:

prefix summed processor speed array.

getRandomProcessorsDouble

public static PrefixSum getRandomProcessorsDouble(int p,
                                                  int seed,
                                                  int range)

Returns random processors. The chosen processor indices are uniformly distributed doubles in the range [1, range].

Parameters:

p - the number of processors.

seed - the seed.

range - the range.

Returns:

prefix summed processor speed array.

getRandomProcessorsNormal

public static PrefixSum getRandomProcessorsNormal(int p,
                                                  int seed,
                                                  double mean,
                                                  double deviation)

Returns random processors. The chosen processor indices are normally distributed doubles with mean and deviation as given.

Parameters:

p - the number of processors.

seed - the seed.

mean - the mean.

deviation - the standard deviation.

Returns:

prefix summed processor speed array.

getRandomProcessorsNormalSquare

public static PrefixSum getRandomProcessorsNormalSquare(int p,
                                                        int seed,
                                                        double mean,
                                                        double deviation)

Returns random processors. The chosen processor indices are normal-squared distributed doubles with mean and deviation as given.

Parameters:

p - the number of processors.

seed - the seed.

mean - the mean.

deviation - the standard deviation.

Returns:

prefix summed processor speed array.

fullGc

public static void fullGc()

performs a full garbage collection.

getRandomProcessors

public static PrefixSum getRandomProcessors(int p)

The default random processor chain factory.

Parameters:

p - the number of processors.

Returns:

the prefix summed processor-chain.

getRandomOrdering

public static PrefixSum getRandomOrdering(PrefixSum origPSum,
                                          int seed)

returns a prefix-summed random ordering of the given prefix summed chain.

Parameters:

origPSum - original prefix sum.

seed - seed.

Returns:

the prefix summed reordered chain.

getMax

public static double getMax(PrefixSum pSum)

max item of the prefix summed array. Note that, this method searches the items one-by-one, resulting in an O(N)-time complexity.

Parameters:

pSum - the prefix summed array.

Returns:

max.

getMin

public static double getMin(PrefixSum pSum)

min item of the prefix summed array. Note that, this method searches the items one-by-one, resulting in an O(N)-time complexity.

Parameters:

pSum - the prefix summed array.

Returns:

min.

getStatistics

public static RunningStatistics getStatistics(PrefixSum sequence)

calculates and returns the statistics based on the sequence.

Parameters:

sequence - the sequence to be investigated.

Returns:

the statistics.