- Community Home
- >
- Servers and Operating Systems
- >
- Operating Systems
- >
- Operating System - Linux
- >
- Re: Different results with F90 higher level optimi...
Operating System - Linux
1753365
Members
6116
Online
108792
Solutions
Forums
Categories
Company
Local Language
юдл
back
Forums
Discussions
Forums
- Data Protection and Retention
- Entry Storage Systems
- Legacy
- Midrange and Enterprise Storage
- Storage Networking
- HPE Nimble Storage
Discussions
Discussions
Discussions
Forums
Forums
Discussions
юдл
back
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
- BladeSystem Infrastructure and Application Solutions
- Appliance Servers
- Alpha Servers
- BackOffice Products
- Internet Products
- HPE 9000 and HPE e3000 Servers
- Networking
- Netservers
- Secure OS Software for Linux
- Server Management (Insight Manager 7)
- Windows Server 2003
- Operating System - Tru64 Unix
- ProLiant Deployment and Provisioning
- Linux-Based Community / Regional
- Microsoft System Center Integration
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Blogs
Information
Community
Resources
Community Language
Language
Forums
Blogs
Go to solution
Topic Options
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО10-25-2007 01:43 AM
тАО10-25-2007 01:43 AM
We have a large (and old) code that performs heavy floating-point operations (thermal-hydraulic transient analysis). We have been compiling the code with +O1 optimization and with some other options, which yield identical results as the debug version. When we tried higher level of optimization, +O2 or +O3, we noticed that some problems yield different numerical results relative to the +O1 or debug version and sometimes even crash. I used the following options for conservative optimization to no avail.
+Ofltacc=strict +Onomoveflops +Oparmsoverlap +DAportable +Ofenvaccess
I would like to know if there are other options that can be used to avoid this much numerical sensitivity when going to higher level compiler optimization.
The operating system is:
HP-UX B.11.11 U 9000/785
Fortran version:
HP F90 v2.8.2
Thanks very much,
-Vefa Kucukboyaci
Solved! Go to Solution.
3 REPLIES 3
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО10-25-2007 06:17 PM
тАО10-25-2007 06:17 PM
Solution
>I used the following options for conservative optimization to no avail.
+Ofltacc=strict +Onomoveflops +Oparmsoverlap +DAportable +Ofenvaccess
(You may want to remove +DAportable.)
You seem to have used all of the PA options that control accuracy.
>sometimes even crash.
Any particular signal?
You should contact the Response Center to have them look into your issues.
+Ofltacc=strict +Onomoveflops +Oparmsoverlap +DAportable +Ofenvaccess
(You may want to remove +DAportable.)
You seem to have used all of the PA options that control accuracy.
>sometimes even crash.
Any particular signal?
You should contact the Response Center to have them look into your issues.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО10-26-2007 08:49 AM
тАО10-26-2007 08:49 AM
Re: Different results with F90 higher level optimization
Thanks very much for your response.
Removing +DAportable has helped somewhat; now results are closer but still not identical.
I might have misled you by using the word "crash". I realized it was the code that was stopping because the transient calculations were going to a different and unacceptable physical state (i.e., below some limits etc..). It is actually really bothering to see how sensitive the FP operations in this code are.
Anyways, I will keep trying few other things, and most likely we will keep running the code with O1 optimization, which is slow but at least consistent with the debug version.
Thanks again...
-Vefa
Removing +DAportable has helped somewhat; now results are closer but still not identical.
I might have misled you by using the word "crash". I realized it was the code that was stopping because the transient calculations were going to a different and unacceptable physical state (i.e., below some limits etc..). It is actually really bothering to see how sensitive the FP operations in this code are.
Anyways, I will keep trying few other things, and most likely we will keep running the code with O1 optimization, which is slow but at least consistent with the debug version.
Thanks again...
-Vefa
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО10-26-2007 02:55 PM
тАО10-26-2007 02:55 PM
Re: Different results with F90 higher level optimization
>I will keep trying few other things, and most likely we will keep running the code with O1 optimization, which is slow but at least consistent with the debug version.
I talked with our IPF expert and said this shouldn't happen on our Integrity compilers. With the right options, increasing the opt level should provide the same answers.
If you have a support contract you could contact the Response Center to see if this is a bug with the PA-RISC optimizer.
Have you looked at the "HP-UX Floating-Point Guide: HP 9000 Computers"?
http://docs.hp.com/en/B3906-90006/index.html
I talked with our IPF expert and said this shouldn't happen on our Integrity compilers. With the right options, increasing the opt level should provide the same answers.
If you have a support contract you could contact the Response Center to see if this is a bug with the PA-RISC optimizer.
Have you looked at the "HP-UX Floating-Point Guide: HP 9000 Computers"?
http://docs.hp.com/en/B3906-90006/index.html
- Tags:
- FP guide
The opinions expressed above are the personal opinions of the authors, not of Hewlett Packard Enterprise. By using this site, you accept the Terms of Use and Rules of Participation.
News and Events
Support
© Copyright 2024 Hewlett Packard Enterprise Development LP