random-walk-R3.py

# Copyright (c) 2017 N.P. Rougier and F.C.Y. Benureau
# Release under the BSD 2-clause license
# Tested with 64-bit CPython 3.6.2 / macOS 10.12.6
import sys, subprocess, datetime, random

def compute_walk():
    x = 0
    walk = []
    for i in range(10):
        if random.uniform(-1, +1) > 0:
            x += 1
        else:
            x -= 1
        walk.append(x)
    return walk

# If repository is dirty, don't run anything
if subprocess.call(("git", "diff-index",
                    "--quiet", "HEAD")):
    print("Repository is dirty, please commit first")
    sys.exit(1)

# Get git hash if any
hash_cmd = ("git", "rev-parse", "HEAD")
revision = subprocess.check_output(hash_cmd)

# Unit test
random.seed(42)
assert compute_walk() == [1,0,-1,-2,-1,0,1,0,-1,-2]

# Random walk for 10 steps
seed = 1
random.seed(seed)
walk = compute_walk()

# Display & save results
print(walk)
results = {
    "data"     : walk,
    "seed"     : seed,
    "timestamp": str(datetime.datetime.utcnow()),
    "revision" : revision,
    "system"   : sys.version}
with open("results-R3.txt", "w") as fd:
    fd.write(str(results))