byteswap ifort question

[Arlindo da Silva]

On Wed, Jul 15, 2009 at 6:18 PM, JEFFREY S GALL <jsg229 at psu.edu> wrote:

> When I compile a FORTRAN program using ifort, I need to add the
> command 'OPTIONS byteswapped'


Do not use "OPTIONS byteswapped", this construct is deprecated. Instead,
explicitly state the endianess of of your data

OPTIONS little_endian

(if you are using ifort, good chance you have a little endian machine.)
Although you can tell the compiler to automatically convert your data to big
endian as Ryo suggests,

    $ ifort -convert big_endian yourprog.f90

this is not recommended unless you expect to use your data on a big-endian
machine (these are becoming more of a rarity these days.)  If you do this
big-endian conversion, every time you use your data on a little endian
machine (such as i686, x86_64 platforms, including Linux, Windows, Mac OS
X/Intel) GrADS will be doing a byte swap for each byte it reads - kind of
inefficient.

   Arlindo




--
Arlindo da Silva
dasilva at alum.mit.edu
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