How to shorten calculation time for dynamic analysis

RE: How to shorten calculation time for dynamic analysis

Stefanos Papavasileiou — Wed, 30 Mar 2022 15:36:03 GMT

Sure, if you specify each of the phases to run on 1 core then if you have 8 cores you can run up to 8 phases at the same time.

Just set the following parameter to 1 core:

RE: How to shorten calculation time for dynamic analysis

Mustafa Erten — Wed, 30 Mar 2022 13:55:23 GMT

Thank you Stefanos for your answer, I have another question. I have seven dynamic analysis cases and all of them start after the initial phase. Basically, I am looking at the performance of the slope for different earthquake events. Since these dynamic cases are not dependent on each other, can I run them simultaneously using different CPUs?

RE: How to shorten calculation time for dynamic analysis

Stefanos Papavasileiou — Wed, 30 Mar 2022 09:42:00 GMT

Dear Mustafa,

When using more cores, the calculation kernel will need to divide the calculation over the different processors (cores/CPUs). However, this comes with some costs: the calculation needs to be split, and then the results should be merged. After some testing, we found out that a small number of elements divided over too many cores actually becomes slower to calculate. For that reason, we have a threshold value for the number of degrees of freedom (dof) per core, which is about 10,000 dofs.
So, if this number becomes too low, we just use fewer cores not to slow down the calculation.

For larger models, you will see an increase in the number of cores used. Note that your model contains 1235 elements in total.

For some more background on cores and performance, please see:

https://communities.bentley.com/products/geotechnical1/w/wiki/45817/multicore-cpu-and-32-64-bit
https://communities.bentley.com/products/geotechnical1/w/wiki/45816/is-plaxis-3d-enabled-for-multicore
includes info about running parallel phases simultaneously