Your local machine is making use of maxNumCompThreads, which is set to the number of physical cores on your machine. The 'parallelism' is threads, not processes, that are spawned by eigs onto those cores.
When you call batch, you can pass it a pool argument, specifying how many workers (processes) should start up. batch will request one additional worker to act as your proxy MATLAB client. For example,
will reqest 4 workers run on your cluster. As you've noticed, you don't need additional workers for your code. You just need the single worker that batch will request, which in turn needs to spawn threads (across several cores).
Your question then is, why does eigs run with multiple threads locally, but only a single thread on the cluster? By default, MATLAB will only request a single thread per worker. To increase this, set the number of threads per worker, as such (8 is only an example)
c = parcluster(name-of-cluster-profile);
c.NumThreads = 8;
j = c.batch('myfile');
If, for some reason, that doesn't work, you can call maxNumCompThreads in myfile. The caveat is that setting NumThreads should request additional cores (needed for the additional threads). If setting NumThreads didn't work, you'll only get a single core. Then, calling maxNumCompThreads may have one of the following consequences
- Starting threads on cores you don't own
- Starting all on the same core, if cgroups are implemented
Neither is desireable.
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