#!/usr/bin/python

import pylab as pl

from polyfuncs import polsize

def clcoef(Q, degQ):

    """Function to clear zero leading coefficient matrices

    of a Polynomial Matrix"""

    rQ, cQ = polsize(Q, degQ)

    if pl.allclose(Q, pl.zeros_like(Q)):

        P = pl.zeros((rQ,cQ))

        degP = 0

    else:

        P, degP = Q, degQ

        rP, cP = rQ, cQ

        j = degP

        while j>=0:

            if pl.norm(P[:, -cP:], pl.inf) < 1e-8 *pl.norm(P, pl.inf):

                P = P[:, :j*cP]

                degP = degP-1

            else:

                j=0

            j -= 1

    return P, degP

if __name__== "__main__":

    s = """P = pl.array([[1, 2, 3, 4, 0, 0, 0, 0],

           [9, 10, 11, 12, 0, 0, 0, 0],

           [5, 6, 7, 8, 0, 0, 0, 0]])"""

    t = """degP = 3"""

    print s, t

    exec(s)

    exec(t)

    print clcoef(P, degP)