[pypy-commit] benchmarks default: finding mersenne primes. finally some unproblematic microbench

[Raemi]

Author: Remi Meier <remi.meier at inf.ethz.ch>
Branch: 
Changeset: r273:fd2da4da8f33
Date: 2014-07-22 17:26 +0200
http://bitbucket.org/pypy/benchmarks/changeset/fd2da4da8f33/

Log:	finding mersenne primes. finally some unproblematic microbench

diff --git a/multithread/mersenne/mersenne.py b/multithread/mersenne/mersenne.py
new file mode 100644
--- /dev/null
+++ b/multithread/mersenne/mersenne.py
@@ -0,0 +1,89 @@
+# -*- coding: utf-8 -*-
+
+
+
+import sys
+import time, random
+from common.abstract_threading import (
+    atomic, Future, set_thread_pool, ThreadPool,
+    hint_commit_soon, print_abort_info)
+
+import itertools
+from collections import deque
+
+
+from sys import stdout
+from math import sqrt, log
+
+
+def chunks(iterable, size):
+    it = iter(iterable)
+    item = list(itertools.islice(it, size))
+    while item:
+        yield item
+        item = list(itertools.islice(it, size))
+
+
+def is_prime ( p ):
+    if p == 2: return True # Lucas-Lehmer test only works on odd primes
+    elif p <= 1 or p % 2 == 0: return False
+    else:
+        for i in range(3, int(sqrt(p))+1, 2 ):
+            if p % i == 0: return False
+    return True
+
+def is_mersenne_prime ( p ):
+    if p == 2:
+        return True
+    else:
+        m_p = ( 1 << p ) - 1
+        s = 4
+        for i in range(3, p+1):
+            s = (s ** 2 - 2) % m_p
+        return s == 0
+
+
+def work(ps, counter, upb_count):
+    if counter[0] >= upb_count:
+        return
+
+    for p in ps:
+        with atomic:
+            if is_prime(p) and is_mersenne_prime(p):
+                #print p
+                counter[0] += 1
+        if counter[0] >= upb_count:
+            break
+
+
+def run(threads=2, n=2000):
+    threads = int(threads)
+    n = int(n)
+
+    set_thread_pool(ThreadPool(threads))
+
+
+    precision = n   # maximum requested number of decimal places of 2 ** MP-1 #
+    long_bits_width = precision * log(10, 2)
+    upb_prime = int( long_bits_width - 1 ) / 2    # no unsigned #
+    upb_count = 45      # find 45 mprimes if int was given enough bits #
+
+    print " Finding Mersenne primes in M[2..%d]:" % upb_prime
+
+    counter = [0]
+    fs = []
+    for ps in chunks(xrange(2, upb_prime+1), 500):
+        fs.append(Future(work, ps, counter, upb_count))
+
+    [f() for f in fs]
+    print "found", counter[0]
+
+    # shutdown current pool
+    set_thread_pool(None)
+
+    return
+
+
+
+if __name__ == "__main__":
+    run()