Jug

Jug Documentation and Tutorial

Short Jug example

Here is a one minute example. Save the following to a file called primes.py:

from jug import TaskGenerator
from time import sleep

@TaskGenerator
def is_prime(n):
    sleep(1.)
    for j in range(2,n-1):
        if (n % j) == 0:
            return False
    return True

primes100 = map(is_prime, list(range(2,101)))

Of course, this is only for didactical purposes, normally you would use a better method. Similarly, the sleep function is so that it does not run too fast.

Now type jug status primes.py to get:

Task name                    Waiting       Ready    Finished     Running
------------------------------------------------------------------------
primes.is_prime                    0          99           0           0
........................................................................
Total:                             0          99           0           0

This tells you that you have 99 tasks called primes.is_prime ready to run. So run jug execute primes.py &. You can even run multiple instances in the background (if you have multiple cores, for example). After starting 4 instances and waiting a few seconds, you can check the status again (with jug status primes.py):

Task name                    Waiting       Ready    Finished     Running
------------------------------------------------------------------------
primes.is_prime                    0          63          32           4
........................................................................
Total:                             0          63          32           4

Now you have 32 tasks finished, 4 running, and 63 still ready. Eventually, they will all finish and you can inspect the results with jug shell primes.py. This will give you an ipython shell. The [primes100]{.title-ref} variable is available, but it is an ugly list of [jug.Task]{.title-ref} objects. To get the actual value, you call the [value]{.title-ref} function:

In [1]: primes100 = value(primes100)

In [2]: primes100[:10]
Out[2]: [True, True, False, True, False, True, False, False, False, True]

Jug links

• Jug documentation
• Jug Manuscript: Jug: Software for parallel reproducible computation in Python by Luis Pedro Coelho in JORS 2017