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Re: multimin question
- To: Fabrice Rossi <rossi at ufrmd dot dauphine dot fr>
- Subject: Re: multimin question
- From: Brian Gough <bjg at network-theory dot co dot uk>
- Date: Mon, 10 Apr 2000 21:24:01 +0100 (BST)
- Cc: GSL mailing list <gsl-discuss at sourceware dot cygnus dot com>, Dave Morrison <dave at bnl dot gov>
- References: <38EF97A6.C8386086@bnl.gov><38F205DE.2A963773@ufrmd.dauphine.fr>
Assuming this is on intel, adding a call gsl_ieee_env_setup() and
running the test program with GSL_IEEE_MODE=double-precision will
avoid the use of extended-precision registers. Declaring the relevant
variables "volatile" should have the same effect. This will let you
test your theory for any -O level.
If extended precision is the problem then the simplest workaround is
"volatile", with a comment explaining why it is needed.
Fabrice Rossi writes:
> This is really beyond my understanding of compilers and of ieee
> floating point representation... I guess it might be related to the
> fact that registers store floating with a higher precision than
> requested by ieee. Anyway, I don't know what to do and I really
> need help on this point.
> Fabrice Rossi