Vectorization of transcendentals with gfortran.

[Toon Moene]

On 2/5/19 10:57 AM, Martin Liška wrote:

> Great, I'm very curious about a speed up you application got?
> 
> Martin

Jerry asked this too (in private). My answer to him was:

'No [speed up], but I didn't expect any, for our code. This was all 
developed in a time that "everyone knew" transcendentals were very 
expensive, so the code works with a lot of pre-computed tables - and 
that's were the sin/cos/log/exp comes from ...'

Note that most weather codes ran on Crays in those days and therefore 
used 64 bit reals with no choice (I run it at home using 32 bit reals - 
works.).

The cost of transcendentals was such a problem that the Cray run time 
library even offered a "half-precision" exp function - just for speed - 
to those of us who had no use for the extra 30-odd bits of mantissa.

Kind regards,

-- 
Toon Moene - e-mail: toon@moene.org - phone: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
At home: http://moene.org/~toon/; weather: http://moene.org/~hirlam/
Progress of GNU Fortran: http://gcc.gnu.org/wiki/GFortran#news