**by Neal R. Wagner**

**Copyright © 2002 by Neal R. Wagner. All rights reserved.**

**
NOTE: This site is obsolete. See book draft (in PDF):**

Java supplies a function to calculate natural logs, base
** e = 2.718281828459045**. To calculate logs
to other bases, you need to multiply by a fixed constant:
for a log base

// Logs.java: try out logarithm formulas public class Logs { // main function to try out Logs class public static void main (String[] args) { System.out.println("log base 2 of 1024 = " + log2(1024)); System.out.println("log base 10 of 1000 = " + log10(1000)); System.out.println("log 2 = " + Math.log(2)); System.out.println("1/log 2 = " + 1/Math.log(2)); System.out.println("log base 10 of 2 = " + log10(2)); } // end of main// log2: Logarithm base 2 public static double log2(double d) { return Math.log(d)/Math.log(2.0); } // log10: Logarithm base 10 public static double log10(double d) { return Math.log(d)/Math.log(10.0); }} /* Output: log base 2 of 1024 = 10.0 log base 10 of 1000 = 2.9999999999999996 log 2 = 0.6931471805599453 1/log 2 = 1.4426950408889634 log base 10 of 2 = 0.30102999566398114 */