1.7. PyCOMPSs: Using objects, lists, and synchronization. Managing fault-tolerance.

In this example we will see how classes and objects can be used from PyCOMPSs, and that class methods can become tasks. The example also illustrates the current fault-tolerance management provided by the runtime.

Import the PyCOMPSs library

import pycompss.interactive as ipycompss

Start the 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=False, debug=False)

********************************************************
**************** PyCOMPSs Interactive ******************
********************************************************
*          .-~~-.--.           ______         ______   *
*         :         )         |____  \       |____  \  *
*   .~ ~ -.\       /.- ~~ .      __) |          __) |  *
*   >       `.   .'       <     |__  |         |__  |  *
*  (         .- -.         )   ____) |   _    ____) |  *
*   `- -.-~  `- -'  ~-.- -'   |______/  |_|  |______/  *
*     (        :        )           _ _ .-:            *
*      ~--.    :    .--~        .-~  .-~  }            *
*          ~-.-^-.-~ \_      .~  .-~   .~              *
*                   \ \ '     \ '_ _ -~                *
*                    \`.\`.    //                      *
*           . - ~ ~-.__\`.\`-.//                       *
*       .-~   . - ~  }~ ~ ~-.~-.                       *
*     .' .-~      .-~       :/~-.~-./:                 *
*    /_~_ _ . - ~                 ~-.~-._              *
*                                     ~-.<             *
********************************************************
* - Starting COMPSs runtime...                         *
* - Log path : /home/user/.COMPSs/Interactive_07/
* - PyCOMPSs Runtime started... Have fun!              *
********************************************************

Importing task and arguments directionality modules

Import task module before annotating functions or methods

from pycompss.api.api import compss_barrier
from pycompss.api.api import compss_wait_on
from pycompss.api.task import task
from pycompss.api.parameter import *

Declaring a class

%%writefile my_shaper.py

from pycompss.api.task import task
from pycompss.api.on_failure import on_failure
from pycompss.api.parameter import IN
import sys

class Shape(object):
    def __init__(self,x,y):
        self.x = x
        self.y = y
        description = "This shape has not been described yet"

    @task(returns=int, target_direction=IN)
    def area(self):
        return self.x * self.y

    @task()
    def scaleSize(self,scale):
        self.x = self.x * scale
        self.y = self.y * scale

    # management='IGNORE' | 'RETRY' | 'FAIL' | 'CANCEL_SUCCESSORS'
    @on_failure(management="CANCEL_SUCCESSORS")
    @task()
    def downScale(self,scale):
        if (scale <= 0):
            sys.exit(1)
        else:
            self.x = self.x/scale
            self.y = self.y/scale

    @task(returns=int, target_direction=IN)
    def perimeter(self):
        return 2 * self.x + 2 * self.y

    def describe(self,text):
        self.description = text

    @task(target_direction=IN)
    def infoShape(self):
        print('Shape x=', self.x, 'y= ', self.y)

Overwriting my_shaper.py

Invoking tasks

from my_shaper import Shape

my_shapes = []
my_shapes.append(Shape(100,45))
my_shapes.append(Shape(50,50))
my_shapes.append(Shape(10,100))
my_shapes.append(Shape(20,30))
my_shapes.append(Shape(200,25))

all_perimeters = []

i=4
for this_shape in my_shapes:
    this_shape.scaleSize(2)
    this_shape.area()
    i = i - 1
    this_shape.downScale(i)
    all_perimeters.append(this_shape.perimeter())

Synchronizing results from tasks

all_perimeters = compss_wait_on(all_perimeters)
print(all_perimeters)

WARNING: Could not retrieve the object /home/user/.COMPSs/Interactive_07/tmpFiles/pycompsssqo27tt9/de05df52-7264-11ee-96af-c8f75057b763-12 since the task that produces it may have been IGNORED or CANCELLED. Please, check the logs. Returning None.
WARNING: Could not retrieve the object /home/user/.COMPSs/Interactive_07/tmpFiles/pycompsssqo27tt9/de05df52-7264-11ee-96af-c8f75057b763-15 since the task that produces it may have been IGNORED or CANCELLED. Please, check the logs. Returning None.
[193.33333333333334, 200.0, 440.0, None, None]

INFO: The ERRMGR displayed some error or warnings.

Stop the runtime

ipycompss.stop(sync=False)

********************************************************
***************** STOPPING PyCOMPSs ********************
********************************************************
Checking if any issue happened.

[ERRMGR]  -  WARNING: file /home/user/.COMPSs/Interactive_07/tmpFiles/pycompsssqo27tt9/de05df52-7264-11ee-96af-c8f75057b763-12:linux-2e63 was accessed but the file information not found. Maybe it has been previously canceled
[ERRMGR]  -  WARNING: No version available. Returning null
[ERRMGR]  -  WARNING: file /home/user/.COMPSs/Interactive_07/tmpFiles/pycompsssqo27tt9/de05df52-7264-11ee-96af-c8f75057b763-15:linux-2e63 was accessed but the file information not found. Maybe it has been previously canceled
[ERRMGR]  -  WARNING: No version available. Returning null

Warning: some of the variables used with PyCOMPSs may
         have not been brought to the master.
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