# PARALLEL

An optionally section to run PoPy in parallel to increase the speed of the program by separating tasks amongst the different nodes of a computer.

You can add the PARALLEL section to the following scripts:-

- Tut Script
- Gen Script
- Fit Script
- Sim Script
- Comp Script
- MTut Script
- MGen Script
- MFit Script
- MSim Script
- MComp Script
- Grph Script
- Vpc Script

i.e. Any script that does a significant amount of processing over all individuals in the population.

If you leave out the parallel section then the script will be executed in serial, i.e. using one processor.

## Example PARALLEL section

You can make your PoPy script use parallel processing by adding the following:-

    PARALLEL:
        MPI_WORKERS:
            n_workers: 4

This section invokes the ‘MPI_WORKERS’ parallel method, that uses mpi to process individuals in parallel where possible.

The ‘n_workers’ parameter requests 4 separate processors. You can also use:-

    PARALLEL:
        MPI_WORKERS:
            n_workers: auto

To utilise all processors on a given machine.

Note if you leave out the the ‘PARALLEL’ section from your script, this is equivalent to using the following:-

    PARALLEL: {SINGLE: {}}

That requests using a single processor.