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From: martin@entropy.ms.washington.edu (Don Martin)
Newsgroups: comp.lang.c
Subject: Re: float ==
Message-ID: <562@entropy.ms.washington.edu>
Date: Wed, 8-Apr-87 23:42:34 EST
Article-I.D.: entropy.562
Posted: Wed Apr  8 23:42:34 1987
Date-Received: Mon, 13-Apr-87 04:10:07 EST
References: <6529@brl-adm.ARPA>
Organization: UW MathStat, Seattle
Lines: 14
Summary: float == sometimes useful


There are several occasions where an exact test of equality
is needed for floating point numbers. One is for missing
value codes in statistical systems. I have also senn a few
numerical algorithms that are designed to converge for all
bits in a number.

I admit that usually when you see float == float that it is
a beginners error but there are some legit uses for this
construct. Various numerical analysts have complained about
APL which calls float1 == float2 if abs( float1 -float2 )
is less than "fuzz".

Don Martin     martin@entropy