This isn't really easy to solve. I'm only (a little) familiar with Chapel which I think is the most widely used high level HPC language; how data is distributed

This isn't really easy to solve. I'm only (a little) familiar with Chapel which I think is the most widely used high level HPC language; how data is distributed needs a lot of thought and is specified by the programmer according to language constructs of "locale" and "distribution". The other hard problem an HPC language needs to handle is error handling. What happens when a processor goes down, data isn't received in a timely fashion, etc. How a data processing job might get rerouted to a different server and how intermediate data calculations might get checkpointed so the loss of one result doesn't mean redoing the whole computation.