Optimise my ray tracer - comp.lang.java.programmer

Message from discussion Optimise my ray tracer

Patricia Shanahan

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More options 2 Jun 2005, 19:46

Newsgroups: comp.lang.java.programmer

From: Patricia Shanahan <p...@acm.org>

Date: Thu, 02 Jun 2005 18:46:57 GMT

Local: Thurs 2 Jun 2005 19:46

Subject: Re: Optimise my ray tracer

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Lasse Reichstein Nielsen wrote:
> Jon Harrop <use...@jdh30.plus.com> writes:
...
>> 2. Where is the floating-point machine epsilon in the
>> Java libraries?

> I'm not sure what epsilon is to you, but you might want
> Double.MIN_VALUE, the smalles positive value
> representable as a double.

That is one definition of machine epsilon.

The other one I've seen is the gap between 1.0 and the
smallest number greater than 1.0. For Java doubles, it is
Math.ulp(1.0). In general, the gap between a Java double d
and the smallest double greater than d is Math.ulp(d).

Patricia

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