org.apache.lucene.util

Class MathUtil

java.lang.Object

org.apache.lucene.util.MathUtil

public final class MathUtil
extends Object

Math static utility methods.

Method Summary

Methods

Modifier and Type	Method and Description
static long	gcd(long a, long b) Return the greatest common divisor of a and b, consistently with BigInteger.gcd(BigInteger).
static int	log(long x, int base) Returns x <= 0 ? 0 : Math.floor(Math.log(x) / Math.log(base))

Methods inherited from class java.lang.Object

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

Method Detail

log

public static int log(long x,
      int base)

Returns x <= 0 ? 0 : Math.floor(Math.log(x) / Math.log(base))

Parameters:

base - must be > 1

gcd

public static long gcd(long a,
       long b)

Return the greatest common divisor of a and b, consistently with BigInteger.gcd(BigInteger).

NOTE: A greatest common divisor must be positive, but 2^64 cannot be expressed as a long although it is the GCD of Long.MIN_VALUE and 0 and the GCD of Long.MIN_VALUE and Long.MIN_VALUE. So in these 2 cases, and only them, this method will return Long.MIN_VALUE.