Re: speed up calculation suggestions

rleavitt@xxxxxxxxxxxxxxxx wrote:
I am an actuary and not a system professional and so please bear with
me. We use Fortran for some or our calculations and are being hampered
by long calculation times. There is nothing fancy in the code... I
process many millions of records from text files through some fairly
simple calculations, and write out the results. I want to speed up
this process, but am really not sure where to devote my efforts. I
have a new (dual core) windows XP machine with F95 compiled by
absoft. (I think version 7.5). I do not have much system support and
not too much time for experimentation, but am willing to tinker a
little. I am interested in other's thoughts.

Options:

1. Optimize my code: I am not sure what this means... It is pretty
stripped down now.
2 Get an updated compiler (any suggestions?)
3 Switch to Linux
4. Vectorize my code and use multiple processors (not sure how hard
this is).
5. Upgrade my computer (are some CPU's better at computation than
others?)
6. Other suggestions?

Of course, I do several of things, but really want help deciding what
will give me the biggest improvement for the least effort.

Thanks, Rick

The obvious things to do first are:

(i) try out any opimisation options available for your compiler, and conversely, switch off any "debugging"-related options that might affect execution speed;

(ii) look out for the code-related stuff that is well-known to affect exection speed ... in particular (a) use of BACKSPACE when reading files; (b) inefficient ordrering of array subscripts.

As for the dual-core bit, you might try running two jobs simultaneously for greater throughput without effort as, typically, a single run would only use about 50% of your machine's capacity (unless your complier has the capability of targetting multi-core CPU's which is unlikely if it is moderately old). Check in Task Manager to see what CPU usage is like.
.

Relevant Pages

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