PGI User Forum

[tangoman]

MattD,
Thanks. I used PGI 6.1 on SuSE 9.2 x86-64 Linux.
% pgf90 -V

pgf90 6.1-2 64-bit target on x86-64 Linux
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Copyright 2000-2005, STMicroelectronics, Inc. All Rights Reserved.

The follwing test code failed to vectorize.

[MattD]

tangoman,

I tried the code you posted, and I get the same optimization report that you listed (no vectorization).

However, if I change COMPLEX to REAL (for a, b, and sum), it does vectorize.

So it seems that the compiler does not auto-vectorize complex math in this example. I can't think offhand why it wouldn't, though.

You could vectorize it yourself if the performance was really critical. It shouldn't be that tough for this example (as opposed to the problem you presented in the first post in this thread).

You may also get better performance from using SUM rather than loops. I haven't timed it for this example, but it's usually better optomized:

sum1 = sum1 + sum(sum(sum(a*b,1),1),1)

Also, you must rename your `sum' variable if you want to use the SUM function. Array operations are nice. Use them when possible. (They also tend to have a better chance of auto-vectorizing than explicitly written loops.)

Good luck,

-Matt