root/pyx.pyx

#!/usr/bin/env python
# encoding: utf-8
"""
pyx.pyx

Created by Shu Ning Bian on 2007-09-23.
Copyright (c) 2007 . All rights reserved.
"""

import sys
import os
def pix_sum(x,y):
        """Returns a tuple which is the sum of the tuples given"""
        return ((x[0])+y[0], x[1]+y[1], x[2]+y[2])

def pix_diff(x,y):
        """Returns a tuple which is the difference of the tuples given"""
        return ((x[0])-y[0], x[1]-y[1], x[2]-y[2])
        
def pyx_transform_array(input):
        """Performs wavelet transform on the input, destorys input"""
        length = len(input)
        output = [0]*length

        if length%2:
                length=length-1

        while(True):
                length=length/2
                for i from 0 <= i < length:
                        s = pix_sum(input[i*2], input[i*2+1])
                        d = pix_diff(input[i*2], input[i*2+1])
                        output[i] = s
                        output[length+i] = d
                        
                if length == 1:
                        return output
                else:
                        input = output
        raise Exception

def main():
        pass


if __name__ == '__main__':
        main()