ccx-buckling: multi-cpu gives different results

[thschrader]

Hi,
when running a buckling analysis on my intel i7 laptop,
the buckling-factors/eigenforms depending on the number of cpu I have activated in FEM-Preferences.
See also
viewtopic.php?t=74896&start=10

Test files.

DNV_B2_bucklingFrame_extended.FCStd

(22.95 KiB) Downloaded 36 times

buckling_U100_3D.FCStd

(8.83 KiB) Downloaded 33 times

The static/frequency calculations are not affected.
Can someone confirm this?

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.2.29177 +426 (Git)
Build type: Release
Branch: (HEAD detached from 0.20.2)
Hash: 930dd9a76203a3260b1e6256c70c1c3cad8c5cb8
Python 3.8.10, Qt 5.15.2, Coin 4.0.1, Vtk 8.2.0, OCC 7.6.3
Locale: German/Germany (de_DE)
Installed mods: 
  * BIM 2021.12.0
  * CfdOF 1.21.3
  * Curves 0.5.8
  * Defeaturing 1.2.0
  * DesignSPHysics 0.6.3(24-09-2022)
  * dodo
  * fasteners 0.4.4
  * Manipulator 1.4.9
  * Plot 2022.4.17
  * Reinforcement
  * WorkFeature

ccx_multi_cpu.JPG (155.66 KiB) Viewed 506 times

[NewJoker]

I submitted both of your cases using CalculiX without FreeCAD (v0.20) and the results were the same regardless of the number of CPUs. But I can confirm that there's a difference when submitting from FreeCAD 0.20.2. Perhaps it's just a fault of older ccx release.

EDIT: I checked in FreeCAD 0.21 dev and there's no such issue in that version, likely because different release of ccx is used.

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.21.0.31850 (Git)
Build type: Release
Branch: master
Hash: d8d3bb8120ad139cf1eb2acf0be0ae6c297ac7f3
Python 3.10.9, Qt 5.15.6, Coin 4.0.0, Vtk 9.1.0, OCC 7.6.3
Locale: Polish/Poland (pl_PL)

[thschrader]

...
EDIT: I checked in FreeCAD 0.21 dev and there's no such issue in that version, likely because different release of ccx is used.
...

Agree, no more differences between 2x cpu and 6x cpu.
Eigenvalues/Eigenforms are exactly the same.
Thanks for your help.

Done with:

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.21.0.31917 (Git)
Build type: Release
Branch: master
Hash: 4639283b459f9ff9093e289908cc003db8745b82
Python 3.8.16, Qt 5.15.6, Coin 4.0.0, Vtk 9.1.0, OCC 7.6.3
Locale: German/Germany (de_DE)
Installed mods: 
  * BIM 2021.12.0
  * CfdOF 1.21.3
  * Curves 0.5.8
  * Defeaturing 1.2.0
  * DesignSPHysics 0.6.3(24-09-2022)
  * dodo
  * fasteners 0.4.4
  * Manipulator 1.4.9
  * Plot 2022.4.17
  * Reinforcement
  * WorkFeature

frame_buckling.JPG (86.09 KiB) Viewed 381 times