CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Problem to get the double precision

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree1Likes
  • 1 Post By ghorrocks

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   May 2, 2011, 20:48
Default Problem to get the double precision
  #1
Member
 
Domenico
Join Date: Sep 2009
Location: Cranfield
Posts: 48
Rep Power: 16
c120613 is on a distinguished road
Hi All,

in some simulation with CFX solver at the beginning of the job I got the following line:
'Added /SIMULATION CONTROL/EXECUTION CONTROL/EXECUTABLE SELECTION/Double precision = off'

Does anyone knows how I can get back to the double precision?

Thank you in advance

D
c120613 is offline   Reply With Quote

Old   May 3, 2011, 00:11
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,665
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
In the solver manager select the double precision solver. Or if running from the command line use the -double flag. Or stick a item in the CEL in /SIMULATION CONTROL/EXECUTION CONTROL/EXECUTABLE SELECTION/Double precision = on

Any of these options will work.
Lionel Trébuchon likes this.
ghorrocks is offline   Reply With Quote

Old   January 24, 2012, 10:09
Default
  #3
Member
 
Julian Krick
Join Date: May 2009
Location: Guelph
Posts: 88
Rep Power: 16
Julian K. is on a distinguished road
Hi!

I solved the problem by activating "Execution Control > Run Definition > Executable Selection > Double Precision" in the CFX-Pre GUI.
__________________
grid generation: ICEM CFD 13.0
solver: CFX 13.0
Julian K. is offline   Reply With Quote

Old   January 24, 2012, 10:18
Default double precision
  #4
Member
 
Domenico
Join Date: Sep 2009
Location: Cranfield
Posts: 48
Rep Power: 16
c120613 is on a distinguished road
Hi,

in some cases, particularly when the definition file is too big that option goes back to OFF automatically. Although you change that option from the interface does not work anyway. Have you never gone through this problem so far?

Cheers
c120613 is offline   Reply With Quote

Old   January 24, 2012, 17:42
Default
  #5
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,665
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
I have never seen it turn double precision off because it got too big. I have generated def files with double precision which have been too big to run many times so I doubt what you are saying. Sounds like it flipped back to single precision for another reason.
ghorrocks is offline   Reply With Quote

Old   January 26, 2012, 09:07
Default
  #6
Senior Member
 
Lance
Join Date: Mar 2009
Posts: 669
Rep Power: 22
Lance is on a distinguished road
Sometimes I get the same error:

+--------------------------------------------------------------------+
| |
| CFX Command Language Upgrade |
| |
+--------------------------------------------------------------------+

Added /SIMULATION CONTROL/EXECUTION CONTROL/EXECUTABLE SELECTION/Double
Precision = Off.

Deleted /SIMULATION CONTROL/EXECUTION CONTROL/SOLVER STEP
CONTROL/PARALLEL ENVIRONMENT/Number of Processes since we are in
Distributed Parallel mode.

even though I start with the -double switch from the command line. However, I still think that the solver runs with double precision because later on the in the outfile is:

+--------------------------------------------------------------------+
| Mesh Statistics |
+--------------------------------------------------------------------+
| Domain Name | Orthog. Angle | Exp. Factor | Aspect Ratio |
+----------------------+---------------+--------------+--------------+
| | Minimum [deg] | Maximum | Maximum |
+----------------------+---------------+--------------+--------------+
| Default Domain | 17.5 ! | 7 ok | 3439 OK |
+----------------------+---------------+--------------+--------------+

For single precision runs the limit for an "OK" for Aspect Ratio is < 100 while for double precision it is < 10000, and since I get an "OK" for 3439 I assume (hope?) that is runs in double.
Lance is offline   Reply With Quote

Old   January 26, 2012, 17:22
Default
  #7
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,665
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
I did not know that. That must be a new feature they snuck in a recent release. Thanks for the info Lance.
ghorrocks is offline   Reply With Quote

Old   July 8, 2014, 06:54
Default
  #8
Member
 
Derwin Parkin
Join Date: Feb 2010
Posts: 35
Rep Power: 16
derz is on a distinguished road
Hey guys, just wanted to add something here.

I had this problem yesterday...I selected double precision EVERYWHERE possible, even the "Override default" selections, but it kept solving in Single Precision mode. It actually said "Double Precision - On" in the output file towards the top, and then later down decided "Double Precision - Off" was what it wanted to do, for no reason...

I talked to my colleague and he had a similar problem once, and said after rebooting the computer the solver stopped putting in extra lines that no-one requested, so I tried that and, low and behold, it is now solving in double precision.

So bare that in mind...erroneous precision switching may just be some problem that has developed during the many runs preceding it - a Restart is all that's required.
derz is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Double precision & User Fortran Martijn CFX 3 April 4, 2009 06:43
UDF & Double precision; Please help?? Asghari FLUENT 0 January 31, 2007 14:14
how to use double precision ? lenson Siemens 8 August 25, 2006 11:15
Double precision CFX Vanessa CFX 8 August 13, 2006 05:34
Double precision Mark Render Main CFD Forum 6 January 18, 2003 02:21


All times are GMT -4. The time now is 18:23.