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# Python - Paralelismo En Python

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## Paralelismo En Python

Publicado por Fernando_Python (7 intervenciones) el 24/08/2013 07:36:24
Hola quisiera saber de que se trata el modulo llamado Parallel Python.
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## Paralelismo En Python

Publicado por Fernando_Python (7 intervenciones) el 24/08/2013 08:07:14
Me encontre este codigo, alguien me puede explicar como funciona

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```#!/usr/bin/python
```
```# File: sum_primes.py
```
```# Author: VItalii Vanovschi
```
```# Desc: This program demonstrates parallel computations with pp module
```
```# It calculates the sum of prime numbers below a given integer in parallel
```
```# Parallel Python Software: http://www.parallelpython.com
```
` `
`import math, sys, time`
`import pp`
` `
`def isprime(n):`
`    """Returns True if n is prime and False otherwise"""`
`    if not isinstance(n, int):`
`        raise TypeError("argument passed to is_prime is not of 'int' type")`
`    if n < 2:`
`        return False`
`    if n == 2:`
`        return True`
`    max = int(math.ceil(math.sqrt(n)))`
`    i = 2`
`    while i <= max:`
`        if n % i == 0:`
`            return False`
`        i += 1`
`    return True`
` `
`def sum_primes(n):`
`    """Calculates sum of all primes below given integer n"""`
`    return sum([x for x in xrange(2,n) if isprime(x)])`
` `
`print """Usage: python sum_primes.py [ncpus]`
```    [ncpus] - the number of workers to run in parallel,
```
```    if omitted it will be set to the number of processors in the system
```
`"""`
` `
```# tuple of all parallel python servers to connect with
```
`ppservers = ()`
```#ppservers = ("10.0.0.1",)
```
` `
`if len(sys.argv) > 1:`
`    ncpus = int(sys.argv[1])`
```    # Creates jobserver with ncpus workers
```
`    job_server = pp.Server(ncpus, ppservers=ppservers)`
`else:`
```    # Creates jobserver with automatically detected number of workers
```
`    job_server = pp.Server(ppservers=ppservers)`
` `
`print "Starting pp with", job_server.get_ncpus(), "workers"`
` `
```# Submit a job of calulating sum_primes(100) for execution.
```
```# sum_primes - the function
```
```# (100,) - tuple with arguments for sum_primes
```
```# (isprime,) - tuple with functions on which function sum_primes depends
```
```# ("math",) - tuple with module names which must be imported before sum_primes execution
```
```# Execution starts as soon as one of the workers will become available
```
`job1 = job_server.submit(sum_primes, (100,), (isprime,), ("math",))`
` `
```# Retrieves the result calculated by job1
```
```# The value of job1() is the same as sum_primes(100)
```
```# If the job has not been finished yet, execution will wait here until result is available
```
`result = job1()`
` `
`print "Sum of primes below 100 is", result`
` `
`start_time = time.time()`
` `
```# The following submits 8 jobs and then retrieves the results
```
`inputs = (100000, 100100, 100200, 100300, 100400, 100500, 100600, 100700)`
`jobs = [(input, job_server.submit(sum_primes,(input,), (isprime,), ("math",))) for input in inputs]`
`for input, job in jobs:`
`    print "Sum of primes below", input, "is", job()`
` `
`print "Time elapsed: ", time.time() - start_time, "s"`
`job_server.print_stats()`

Alguien me puede explicar como funciona
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