signalproc.algorithms

Class Factorizer

java.lang.Object

signalproc.algorithms.Factorizer

public class Factorizer
extends java.lang.Object

Class Factorizer provides a method, factorize(n), that factors an integer n into its prime factors and returns them as a vector of integers. (It does not return the universal factor 1 in this vector unless n=1.) If given a negative integer, it returns a vector whose first element is -1 and whose remaining elements are the prime factors of n. If given an argument zero, it returns a single element 0.

Factorizer keeps track of previous integers it has factored in a static Hashtable, so that it can return their factorizations instead of doing it anew.

Constructor Summary

Constructors

Constructor and Description
Factorizer(boolean information) Constructor for Factorizer sets the verbose flag, to determine whether comments are written to System.out.

Method Summary

Methods

Modifier and Type	Method and Description
int[]	factorize(int n) Method factorize returns an integer vector containing the prime factors of the integer argument n.

Methods inherited from class java.lang.Object

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

Constructor Detail

Factorizer

public Factorizer(boolean information)

Constructor for Factorizer sets the verbose flag, to determine whether comments are written to System.out.

Method Detail

factorize

public int[] factorize(int n)

Method factorize returns an integer vector containing the prime factors of the integer argument n. Factors with multiplicity greater than 1 are repeated elements of the vector. The method finds all the prime factors less than or equal to the smaller of sqrt(n) and 151. Any prime factor larger than 151 is not found, but the residual quotient of n by all the found factors is returned as the last element of the vector. In this way, the product of all the elements of the vector is n.

If n is negative, the returned vector's first element is -1, then follow the factors of -n.

Parameters:

n - The number to be factored