gfortran -O3

[yuwb]

I have a code complied using gfortran -O3. I currently evaluating Intel Visual Fortran. What will be the equivalent flags to gfortran -O3?I the project properties, Iused Maximize Speed plus Higher Level Optimizations (/O3), however the code compiled by IVF is about 2-3 time slowers? Any suggestions?

[Steven_L_Intel1]

Can you show us the code? Sometimes there are differences not related to optimization (such as the size of I/O records).

[Steven_L_Intel1]

I suggest viewing this to see an overview of the VS environment.

Do you have any OPEN statements with RECL= keywords?

[yuwb]

I only count the time without I/O statements as my I/O are localized in the very beginning and at the very end.

[Steven_L_Intel1]

Try using -fast and see what it does for you.

[yuwb]

Thanks Steve for your help. However, how to activate this option through MS Visual Studio 2010?

[Steven_L_Intel1]

There is not a property for that. I did not realize you were using Visual Studio.

Let me suggest the following property settings:

Optimization > Optimization > O3
Optimization > Interprocedural Optimization > Multifile
Code Generation > Intel Processor-Specific Optimization > /QxHost
Floating Point > Floating Point Model > Fast=2

[yuwb]

I did as you suggested, the code runs for 866.031. Using gfortran, it runs for 438.328.

[Steven_L_Intel1]

Something is very wrong, but it's impossible to say what without seeing the code.

[yuwb]

Can you give me your email address for me to send you the code? I don't want to share it on the forum.

[Steven_L_Intel1]

You can provide it securely through Intel Premier Support. Please ask that the issue be assigned to Steve Lionel.