Hello,

I previously wrote a parfor loop within Matlab that called a GAMS model with the system() function (e.g., system(‘gams storageGAMS’) where storageGAMS is the filename of the model). Each loop run in parallel provided different underlying data to the same Model equations. The computer was able to successfully open 4 different instances of GAMS (for the 4 cores on my computer) and run each model independently. Each worker then creates and reads a results GDX file to bring the results backs to Matlab.

For various reasons, I need to move from Matlab to R. I moved all the code over to R and wrote the loop with the foreach() function. Everything works correctly when I run it in serial computation mode (using %do% instead of %dopar%). When I try to run it in parallel, it quits the loop very quickly and says it can’t find the unloaded GDX file with the results in it. However, it quits the loop fast enough that it couldn’t possibly have even made it to the call to GAMS.

I created the parallel cluster using: cl<-makeCluster(4); registerDoParallel(cl)

I am loading the required packages into the parallel environment (gdxrrw and reshape2). Using .verbose=TRUE I made sure all the required functions and variables were being exported to each worker. Instead of the system() function in R, I tried using shell(), system2() and even the gams() function from the gdxrrw package to call the GAMS model but none of that worked.

Any ideas on how to make this work? It seems like it might have something to do with different underlying mechanics of the system() methods in Matlab and R but I am not savvy enough to understand the computer science.

Thanks,

Mike

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