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From: carl@bdaemon.UUCP (carl)
Newsgroups: net.lang.c
Subject: Re:  C Floating point arithmetic
Message-ID: <336@bdaemon.UUCP>
Date: Fri, 29-Nov-85 13:15:54 EST
Article-I.D.: bdaemon.336
Posted: Fri Nov 29 13:15:54 1985
Date-Received: Thu, 5-Dec-85 04:50:48 EST
References: <123@brl-tgr.ARPA> <1078@lll-crg.ARpA>
Organization: Daemon Assoc., Boulder, CO
Lines: 23

.......
> >analyst should make the determination.  I have seen enough
> >computations that produced total garbage to make me believe
> >that the naive user should get double precision by default.
> >
> 
> This argument is hard to swallow. You are suggesting protection
> for the user by not giving him what he has asked for in his
> code.  Any intelligent scientific programmer trys it both ways
> on his own and determines whether single precision is adequate
> (without the help of a numerical analyst, an analyst is consulted
> when one wants to understand the root of the problem in an attempt
> to rearrange the computation so that single precision is sufficient
> should it fail).  .... more stuff, largely irrelevant .....

I hope never to have the misfortune to have to use one of your programs.
The notion that "trying it both" ways guarantees a program that will never
blow up is patently absurd and in fact accounts for many of the horror
stories that give the use of computers a bad name.  Consulting a numerical
analyst *before* developing a program serves the same purpose as consulting
a statistician well versed in experimental design before starting data
collection -- the chances of wasting the client's money and time are
greatly reduced.