logarithms : Java Glossary

by Roedy Green ©1996-2009 Canadian Mind Products
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logarithms

Java’s Math.log computes natural logarithms (base e=2.718281828…) usually written by engineers as ln. To get base ten common logs, calculate Math.log(x)/Math.log(10). To get base 2 logs, calculate Math.log(x)/Math.log(2). In JDK 1.5+ there is a built-in Math. log10. For computing natural logs of values near 1, there is Math. log1p(x+1).

What you often want is the width in bits, or width in digits.

Learning More

Sun’s Javadoc on the log method : available:

on the web at java.sun.com
in the current JDK 1.6.0_14 or in the old JDK 1.5.0_19 on your local Windows J: drive.

Sun’s Javadoc on the log10 method : available:

on the web at java.sun.com
in the current JDK 1.6.0_14 or in the old JDK 1.5.0_19 on your local Windows J: drive.

Sun’s Javadoc on the log1p method : available:

on the web at java.sun.com
in the current JDK 1.6.0_14 or in the old JDK 1.5.0_19 on your local Windows J: drive.

Sun’s Javadoc on the exp method : available:

on the web at java.sun.com
in the current JDK 1.6.0_14 or in the old JDK 1.5.0_19 on your local Windows J: drive.

Sun’s Javadoc on the expm1 method : available:

on the web at java.sun.com
in the current JDK 1.6.0_14 or in the old JDK 1.5.0_19 on your local Windows J: drive.

bit count
exp
exponentiation
floating point
Jakarta Log4J
logging
power
root
width in bits
width in digits

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