----- Original Message -----
From: "Aleksandar Donev" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, December 15, 2003 4:29 PM
Subject: Re: Fortran 95 on Opteron
> What exactly does 64-bit mode get you for number-crunching programs?
Less than you expect really. Sure you have more registers and a vastly
increased addressable space. You'll be able to run bigger problems
faster but not necessarily with any greater accuracy. If it's a
commodity processor like Intel or AMD the fp calculations may be done
in extended precision but you'll have little or no control over that
unless your compiler supports the extended precision type which few
do. Some compilers support the long double type which is preferable
whether in 32- or 64-bit (addressable space) mode.
--
Ciao,
Gerry T.
______
"In a world in which the price of calculation continues to decrease
rapidly, but the price of theorem proving continues to hold steady or
increase, elementary economics indicates that we ought to spend a
larger and larger fraction of our time on calculation." -- J.W. Tukey.
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