FePest Parallelization of a FEM with Parallelized Equation Solver

Hello,

I'm wondering how FePest encompasses the parallelization of the PEST run and of each FEM model using parallelized equation solvers.

I have a FEFLOW model setup with the SAMG solver, which is supposed to make use of several CPU cores available when it is run independently. Now, If I want to use Pest Parallelization over that model, how will the FEM file be run?. If the master sends one instance of the fem file to a slave computer that is defined as having 3 slaves, Will it send 3 realizations of the fem file to each slave, and leave the slave computer to decide how to make use of other available local CPU cores to solve the FEM?

Another example is when the parallelization of the FePest run is made in the local computer. If one defines the number of slaves of the localhost as the maximum number of CPU cores, and FePest sends one realization of the fem file to each CPU core, seems logical that there will be no room for each CPU core to parallelize the equation solver. But, will it parallelize the equation solver if the number of slaves is less than the maximum number of CPU cores available?

Thanks
Javier.

Yes, that's correct. If three slaves are defined then these three slaves will solve the the model over and over again based on different parameters sets. If you use the default FEFLOW Global Settings then "the slave computer" will decide how to make use of other available local CPU cores to solve the FEM. In a similar fashion, if the the number of slaves is less than the maximum number of CPU cores available then FEFLOW will run inevitably run in parallel.

Thanks a lot Björn.
Javier

[quote author=Björn Kaiser link=topic=3117.msg6970#msg6970 date=1467730195]
Yes, that's correct. If three slaves are defined then these three slaves will solve the the model over and over again based on different parameters sets. If you use the default FEFLOW Global Settings then "the slave computer" will decide how to make use of other available local CPU cores to solve the FEM. In a similar fashion, if the the number of slaves is less than the maximum number of CPU cores available then FEFLOW will run inevitably run in parallel.
[/quote]

Can more than one instance of FEFLOW run on a multi-core machine with a standard license?

If you are using SAMG, is there an advantage to having multiple instances of FEFLOW running if there are fewer cores available to the solver (presumably increasing the run time)?

If you have one single-seat license available you cannot run several models at the same time.

Your second question cannot be answered with yes or no, because other dependencies (e.g. model settings, total number of cores etc.) play an important role. Accordingly, in one configuration the answer would be yes, while in another configuration the answer would be now.

An extreme example: Let's say you have a large number of cores (e.g. 48) and you have only few computational mesh nodes (e.g. 20,000), then this large number of cores would even slow down the simulation, because the internal communication of the threads overprint the actual solution process. In this case fewer cores would be the better option.