Haypat Fourier Transformation Rewrite

fourier_part1_rewrite.py

#!/usr/bin/python
import sys
import cmath

from math import pi

N = 100
c01 = [0.0] * N
cN1 = [0.0] * N
c02 = [0.0] * N
cN2 = [0.0] * N
g1 = [0.0] * N
g2 = [0.0] * N


def readFile(filename):
    """
    Given a filename, yields the lines of the file.
    """
    with open(filename, 'r') as f:
        for line in f:
            yield line


def initialize_cArrays(a):
    global c01, c02, cN1, cN2
    if a[0] == 0:
        c01[int(a[3])] = a[1]
        c02[int(a[3])] = a[2]
    elif a[0] == (N - 1):
        cN1[int(a[3])] = a[1]
        cN2[int(a[3])] = a[2]


def print_results():
    for i in xrange(N-1):
        print i, g1[i], g2[i], "\n\n"


if __name__ == "__main__":
    global g1, g2
    for line in readFile(sys.argv[1]):
        a = [float(x) for x in line.strip()]
        initialize_cArrays(a)
        coeff = (
            cmath.exp(-2j * pi / N * k * a[0]) /
            (N * 100))

        g1[int(a[3])] = (
            g1[int(a[3])] +
            (a[1] -
             c01[int(a[3])] -
             ((a[0]-1) *
              (cN1[int(a[3])] - c01[int(a[3])]) /
              (N-1))) *
            coeff)

        g2[int(a[3])] = (
            g2[int(a[3])] +
            (a[2] -
             c02[int(a[3])] -
             ((a[0]-1) *
              (cN2[int(a[3])] - c02[int(a[3])]) /
              (N-1))) *
            coeff)

    print_results()