#!/usr/bin/python

import pylab as pl

from makezero import makezero

def cindep(S, gap=None):

    E = pl.finfo(float).eps

    if gap == None:

        gap = 1e8

    r, c = pl.atleast_2d(S).shape

    if r>c:

        ind = 0

    else:

        sigma = pl.svd(S)[1]

        l = len(sigma)

        if(sigma[-1]/sigma[0] < (E*max(1, c))):

            ind = 0

        else:

            if pl.any(sigma[:-1]/sigma[1:] >= gap):

                ind = 0

            else:

                ind = 1

    if ind:

        b = pl.array([])

    else:

        A, B = S[r-1,:], S[:r-1,:] 

        b = pl.lstsq(B.T, A.T)[0].T

        b = makezero(b, gap)

        b = b.squeeze()

    return pl.atleast_2d(b)

if __name__== "__main__":

    pass