[jgs55]

Dear Foamers,

I would like to modify the Input/Output of OpenFOAM to be able to pass the required inputs as arguments and receive the corresponding outputs as a return of my call.

I would have my input files (constant, system, 0) saved as RAM variables, and I would save the output files (0+dt) also as RAM variables, instead of saving all these data files as hard disk variables.

I need to do so, because my algorithm requires executing a lot of small cases, and it spends the major part of the time reading/writing data files in the hard disk.

Could anyone give me some guidelines/examples/information of how to implement this modification? Thank you in advance!

[olesen]

Originally Posted by jgs55

Dear Foamers,

I would like to modify the Input/Output of OpenFOAM to be able to pass the required inputs as arguments and receive the corresponding outputs as a return of my call.

I would have my input files (constant, system, 0) saved as RAM variables, and I would save the output files (0+dt) also as RAM variables, instead of saving all these data files as hard disk variables.

I need to do so, because my algorithm requires executing a lot of small cases, and it spends the major part of the time reading/writing data files in the hard disk.

Could anyone give me some guidelines/examples/information of how to implement this modification? Thank you in advance!

I don't see how you would want this to work (ie, how variables are to be persistent in memory between different applications).
The closest I can think of is a RAM-disk, there are probably various FUSE implementations.

[jgs55]

Originally Posted by olesen

I don't see how you would want this to work (ie, how variables are to be persistent in memory between different applications).
The closest I can think of is a RAM-disk, there are probably various FUSE implementations.

Thank you for your reply Mr Olsen. Due to my application, I just need a particular solver (pimpleFoam) running a single time step on each call. So my idea is to modify pimpleFoam.C in order to accept as argument the input files (already done). Then, I need to modify where the variables are read from. For example, in the case of controlDict, I need to change from runTime.system to the variable where I saved the input argument. Summarizing, I would like to have an expresión like this:

p,U,omega,nut,k = pimpleFoam controlDict fvSchemes fvSolution p U omega nut k transportProperties turbulenceProperties polyMesh

[olesen]

Originally Posted by jgs55

Thank you for your reply Mr Olsen. Due to my application, I just need a particular solver (pimpleFoam) running a single time step on each call. So my idea is to modify pimpleFoam.C in order to accept as argument the input files (already done). Then, I need to modify where the variables are read from. For example, in the case of controlDict, I need to change from runTime.system to the variable where I saved the input argument. Summarizing, I would like to have an expresión like this:

p,U,omega,nut,k = pimpleFoam controlDict fvSchemes fvSolution p U omega nut k transportProperties turbulenceProperties polyMesh

Even if I don't really understand how you expect things to hang around in memory, but still exit and restart an application each time. It simply does not fit together unless you are using some other mechanism (eg, a RAM disk) to handle the memory persistence for you.


Having said that, it actually sounds like you have something more like an infinite loop of the pimpleFoam solver, with some modification of fields (on disk or in memory) between each loop. The normal description for that would be some time of a functionObject. There are plenty of ones already available but you'll have to code up your own. The external file coupling function object might be a reasonable place for you to start looking. It has a simple semaphore type of state tracking.