1.8. 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_01/
* - 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

Found task: square

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

Found task: add

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

Found task: multiply

Invoking tasks

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

compss_barrier()

Stop the runtime

ipycompss.stop(sync=True)

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

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

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