#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements.  See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to You under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License.  You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

import sys
from random import random
from operator import add

from pyspark import SparkContext


if __name__ == "__main__":
    if len(sys.argv) == 1:
        print >> sys.stderr, "Usage: pi <master> [<slices>]"
        exit(-1)
    sc = SparkContext(sys.argv[1], "PythonPi")
    slices = int(sys.argv[2]) if len(sys.argv) > 2 else 2
    n = 100000 * slices
    def f(_):
        x = random() * 2 - 1
        y = random() * 2 - 1
        return 1 if x ** 2 + y ** 2 < 1 else 0
    count = sc.parallelize(xrange(1, n+1), slices).map(f).reduce(add)
    print "Pi is roughly %f" % (4.0 * count / n)