1.9. PyCOMPSs: Using constraints

In this example we will how to define task constraints with PyCOMPSs.

Import the PyCOMPSs library

import pycompss.interactive as ipycompss

Starting runtime

Initialize COMPSs runtime Parameters indicates if the execution will generate task graph, tracefile, monitor interval and debug information.

import os
if 'BINDER_SERVICE_HOST' in os.environ:
    ipycompss.start(graph=True, debug=False,
                    project_xml='../xml/project.xml',
                    resources_xml='../xml/resources.xml')
else:
    ipycompss.start(graph=True, monitor=1000, trace=True, debug=False)

********************************************************
**************** PyCOMPSs Interactive ******************
********************************************************
*          .-~~-.--.           ______         ______   *
*         :         )         |____  \       |____  \  *
*   .~ ~ -.\       /.- ~~ .      __) |          __) |  *
*   >       `.   .'       <     |__  |         |__  |  *
*  (         .- -.         )   ____) |   _    ____) |  *
*   `- -.-~  `- -'  ~-.- -'   |______/  |_|  |______/  *
*     (        :        )           _ _ .-:            *
*      ~--.    :    .--~        .-~  .-~  }            *
*          ~-.-^-.-~ \_      .~  .-~   .~              *
*                   \ \ '     \ '_ _ -~                *
*                    \`.\`.    //                      *
*           . - ~ ~-.__\`.\`-.//                       *
*       .-~   . - ~  }~ ~ ~-.~-.                       *
*     .' .-~      .-~       :/~-.~-./:                 *
*    /_~_ _ . - ~                 ~-.~-._              *
*                                     ~-.<             *
********************************************************
* - Starting COMPSs runtime...                         *
* - Log path : /home/user/.COMPSs/Interactive_09/
* - PyCOMPSs Runtime started... Have fun!              *
********************************************************

Importing task and arguments directionality modules

Import task module before annotating functions or methods

from pycompss.api.task import task
from pycompss.api.parameter import *
from pycompss.api.api import compss_barrier
from pycompss.api.constraint import constraint
from pycompss.api.implement import implement

Declaring tasks

Declare functions and decorate with @task those that should be tasks

@constraint(computing_units="2")
@task(returns=int)
def square(val1):
    return val1 * val1

@constraint(computing_units="1")
@task(returns=int)
def add(val2, val3):
    return val2 + val3

@constraint(computing_units="4")
@task(returns=int)
def multiply(val1, val2):
    return val1 * val2

Invoking tasks

for i in range(20):
    r1 = square(i)
    r2 = add(r1,i)
    r3 = multiply(r2,r1)

compss_barrier()

Found task: square
Found task: add
Found task: multiply

Stop the runtime

ipycompss.stop(sync=True)

********************************************************
***************** STOPPING PyCOMPSs ********************
********************************************************
Checking if any issue happened.
Synchronizing all future objects left on the user scope.
Found a future object: r1
Found a future object: r2
Found a future object: r3
********************************************************

print(r1)
print(r2)
print(r3)

361
380
137180