[python-arrayfire] 18/250: Updating the monte carlo pi example

[Ghislain Vaillant]

This is an automated email from the git hooks/post-receive script.

ghisvail-guest pushed a commit to branch debian/master
in repository python-arrayfire.

commit 87ba2911a06bd89208d66868d1b4f18fa539552f
Author: Pavan Yalamanchili <pavan at arrayfire.com>
Date:   Mon Jun 22 10:01:39 2015 -0400

    Updating the monte carlo pi example
    
    - It now has benchmarks and a host version
---
 examples/monte_carlo_pi.py | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/examples/monte_carlo_pi.py b/examples/monte_carlo_pi.py
index cf03c9a..80471c9 100644
--- a/examples/monte_carlo_pi.py
+++ b/examples/monte_carlo_pi.py
@@ -1,13 +1,41 @@
 #!/usr/bin/python
+from random import random
+from time import time
 from arrayfire import (array, randu)
 import arrayfire as af
-import random
+
+#alias range / xrange because xrange is faster than range in python2
+try:
+    frange = xrange  #Python2
+except NameError:
+    frange = range   #Python3
+
 
 def calc_pi_device(samples):
     x = randu(samples)
     y = randu(samples)
     return 4 * af.sum((x * x  + y * y) < 1) / samples
 
+# Having the function outside is faster than the lambda inside
+def in_circle(x, y):
+    return (x*x + y*y) < 1
+
+def calc_pi_host(samples):
+    count = sum(1 for k in frange(samples) if in_circle(random(), random()))
+    return 4 * float(count) / samples
+
+def bench(calc_pi, samples=1000000, iters=25):
+    func_name = calc_pi.__name__[8:]
+    print("Monte carlo estimate of pi on %s with %d million samples: %f" % \
+          (func_name, samples/1e6, calc_pi(samples)))
+
+    start = time()
+    for k in frange(iters):
+        calc_pi(samples)
+    end = time()
+
+    print("Average time taken: %f ms" % (1000 * (end - start) / iters))
+
 if __name__ == "__main__":
-    samples=1000000
-    print("Monte carlo estimate of pi with %d samples: %f" % (samples, calc_pi_device(samples)))
+    bench(calc_pi_device)
+    bench(calc_pi_host)

-- 
Alioth's /usr/local/bin/git-commit-notice on /srv/git.debian.org/git/debian-science/packages/python-arrayfire.git