# Buckling analysis using spooles

**URL:** <https://calculix.discourse.group/t/buckling-analysis-using-spooles/2051>\
**Category:** Uncategorized\
**Created:** [January 31, 2024, 6:54pm UTC](https://calculix.discourse.group/t/buckling-analysis-using-spooles/2051 "2024-01-31T18:54:49Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![tbrown](https://avatars.discourse-cdn.com/v4/letter/t/54ee81/32.png) [@tbrown](https://calculix.discourse.group/u/tbrown)\
**Post date:** [January 31, 2024, 6:54pm UTC](https://calculix.discourse.group/t/buckling-analysis-using-spooles/2051/1 "2024-01-31T18:54:49Z")

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It may have been captured elsewhere already, but using the test example provided “beamb.inp” runnning with Spooles solver and 4 processors gives the following buckle factors for the 1st mode when repeating the step 10 times.  
4.82E+01  
1.75E+00  
4.82E+01  
1.88E+00  
4.82E+01  
4.82E+01  
4.82E+01  
4.82E+01  
4.82E+01  
4.82E+01  
repeating the analysis does not give consistency either. Issue seems to be unique to spooles and OMP\_NUM\_THREADS \>2

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**Author:** ![Calc\_em](https://avatars.discourse-cdn.com/v4/letter/c/43a26b/32.png) [@Calc\_em](https://calculix.discourse.group/u/Calc_em)\
**Post date:** [January 31, 2024, 7:24pm UTC](https://calculix.discourse.group/t/buckling-analysis-using-spooles/2051/2 "2024-01-31T19:24:58Z")

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Today, I reported an issue, part of which is also that Spooles provides inconsistent results in each run when more than 2 cpus are used: [First buckling mode skipped when applied load is much bigger than buckling load · Issue #74 · Dhondtguido/CalculiX · GitHub](https://github.com/Dhondtguido/CalculiX/issues/74)

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**Author:** ![vicmw](https://avatars.discourse-cdn.com/v4/letter/v/6de8d8/32.png) [@vicmw](https://calculix.discourse.group/u/vicmw)\
**Post date:** [February 1, 2024, 7:22pm UTC](https://calculix.discourse.group/t/buckling-analysis-using-spooles/2051/3 "2024-02-01T19:22:47Z")

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Multithreaded Spooles (at least in CCX) is long known to have these bugs. I think nobody should ever use it.

Correct solvers:

- Single threaded Spooles
- MKL Pardiso
- Pastix with mixed precision turned off by an environment variable

Wrong solvers:

- Multithreaded Spooles
- Pastix with mixed precision turned on (default)