#!/usr/bin/env python

""" This module demonstrates some features of the libstreampy

We take an iterable and split it into even and odd then scan it

Comparing a static implementation to the stream.py implementation

Depends on the stream module from https://github.com/aht/stream.py.

"""

from __future__ import print_function

import sys

sys.path.append("~/Code/streaming/libstreampy/")

from time import time

import math

import stream

from stream import fold

from stream import tee

from stream import filter

from stream import item

import operator as ops

if __name__ == '__main__':

if len(sys.argv) != 2:

print("Usage: ./split_xform.py N", file=sys.stderr)

sys.exit(1)

N = int(sys.argv[1])

instream = [float(i) for i in range(N)]

def scan(op, seq):

return l

def my_sqrt(x):

for i in x:

yield math.sqrt(i)

#static computation in a time block

ts = time()

evens = instream[::2]

odds = instream[1::2]

evens = map(math.sqrt, evens)

odds = map(math.sqrt, odds)

even_ans = scan(ops.add, evens)

odd_ans = reduce(ops.add, odds )

static_time = time() - ts

#streaming computation

# create our filters

cong_2 = lambda x: x%2==0

evens = filter(cong_2)

odds = filter(lambda x: not cong_2(x))

ts = time()

# wire the split into the filters

instream >> tee(evens)

instream >> odds

# wire up the map and fold (scan/accumulate)

foldedevens = (evens >> stream.map(math.sqrt) >> fold(ops.add))

print(time() - ts)

sqrtodds = odds >> (stream.Processor(my_sqrt))

print("established the sqrter %f" % (time() - ts))

foldedodd = sqrtodds >> stream.fold(ops.add)

print("made odd folder: %f" % (time() - ts))

# force execution

soans = foldedodd >> item[-1:]

print(soans)

print(time() - ts)

seans = foldedevens >> item[:]

print(time() - ts)

stream_time = time() - ts

#print(even_ans)

#print(seans >> item[:])

#print(odd_ans)

#print(soans >> item[:])

#check the answers

#assert ( seans == (even_ans))

#assert ( soans == (odd_ans))

assert ( seans == list(even_ans))

#assert ( soans == list(odd_ans))

# display the timing information

print("we got the same answer using the streams")

print("static_time: %f, ips: %f" % (static_time, N//static_time))

print("stream_time: %f, ips: %f" % (stream_time, N//stream_time))

print("streaming/static: %f" % (stream_time/static_time))