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From: punch@cps.msu.edu (Bill Punch)
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: FP exceptions under FreeBSD
Date: 13 Jun 1997 15:31:25 GMT
Organization: MSU GARAGe
Lines: 30
Distribution: world
Message-ID: <5nrp4d$obd$1@msunews.cl.msu.edu>
NNTP-Posting-Host: ariel.cps.msu.edu
Originator: punch@ariel.cps.msu.edu
Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:42848

I have a program (called lilgp, a C program for genetic programming)
that I have used on a number of unix and pc platforms. For those that
don't know, a genetic program generates "programs", actually trees of
functions, to perform some operation.

When I do this under FreeBSD, and the programs use floating point
operations, I typically get FPE core dumps. Debugging shows some
pretty standard operations (*, +, etc.), albeit on either some very
large or small numbers (xyz**223, or abc**-103, numbers like
that). These numbers are generated randomly and so what they are
depends on the random seed.

The question is this. I find it hard to believe that this is really a
FP problem. If I run this program under conditions of little memory
usage, it seems to work. If I push it to use more memory, I get FPE
everywhere.  Could be a memory leak or something, but why would it
show up as an FPE? Or is there indeed a problem in FP I should be
aware of?

I'm running this on a portable 75MHz pentium, 16Mb memory. I've tried
various compile flags including -mno-ieee-float (or whatever it is to
turn off ieee fp).

Any help appreciated.

					>>>bill punch<<<
					punch@cps.msu.edu

-- 
Bill Punch