# cypress/FileTransfer/Example: sum_primes.py

File sum_primes.py, 2.5 KB (added by cmaggio, 7 years ago) |
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1 | # File: sum_primes.py |

2 | # Author: VItalii Vanovschi |

3 | # Desc: This program demonstrates parallel computations with pp module |

4 | # It calculates the sum of prime numbers below a given integer in parallel |

5 | # Parallel Python Software: http://www.parallelpython.com |

6 | |

7 | import math, sys, time |

8 | import pp |

9 | |

10 | def isprime(n): |

11 | """Returns True if n is prime and False otherwise""" |

12 | if not isinstance(n, int): |

13 | raise TypeError("argument passed to is_prime is not of 'int' type") |

14 | if n < 2: |

15 | return False |

16 | if n == 2: |

17 | return True |

18 | max = int(math.ceil(math.sqrt(n))) |

19 | i = 2 |

20 | while i <= max: |

21 | if n % i == 0: |

22 | return False |

23 | i += 1 |

24 | return True |

25 | |

26 | def sum_primes(n): |

27 | """Calculates sum of all primes below given integer n""" |

28 | return sum([x for x in xrange(2,n) if isprime(x)]) |

29 | |

30 | print """Usage: python sum_primes.py [ncpus] |

31 | [ncpus] - the number of workers to run in parallel, |

32 | if omitted it will be set to the number of processors in the system |

33 | """ |

34 | |

35 | # tuple of all parallel python servers to connect with |

36 | ppservers = () |

37 | #ppservers = ("10.0.0.1",) |

38 | |

39 | if len(sys.argv) > 1: |

40 | ncpus = int(sys.argv[1]) |

41 | # Creates jobserver with ncpus workers |

42 | job_server = pp.Server(ncpus, ppservers=ppservers) |

43 | else: |

44 | # Creates jobserver with automatically detected number of workers |

45 | job_server = pp.Server(ppservers=ppservers) |

46 | |

47 | print "Starting pp with", job_server.get_ncpus(), "workers" |

48 | |

49 | # Submit a job of calulating sum_primes(100) for execution. |

50 | # sum_primes - the function |

51 | # (100,) - tuple with arguments for sum_primes |

52 | # (isprime,) - tuple with functions on which function sum_primes depends |

53 | # ("math",) - tuple with module names which must be imported before sum_primes execution |

54 | # Execution starts as soon as one of the workers will become available |

55 | job1 = job_server.submit(sum_primes, (100,), (isprime,), ("math",)) |

56 | |

57 | # Retrieves the result calculated by job1 |

58 | # The value of job1() is the same as sum_primes(100) |

59 | # If the job has not been finished yet, execution will wait here until result is available |

60 | result = job1() |

61 | |

62 | print "Sum of primes below 100 is", result |

63 | |

64 | start_time = time.time() |

65 | |

66 | # The following submits 8 jobs and then retrieves the results |

67 | inputs = (100000, 100100, 100200, 100300, 100400, 100500, 100600, 100700) |

68 | jobs = [(input, job_server.submit(sum_primes,(input,), (isprime,), ("math",))) for input in inputs] |

69 | for input, job in jobs: |

70 | print "Sum of primes below", input, "is", job() |

71 | |

72 | print "Time elapsed: ", time.time() - start_time, "s" |

73 | job_server.print_stats() |

74 | |

75 | # Parallel Python Software: http://www.parallelpython.com |