1 #!/usr/bin/python

     2 

     3 import pylab as pl

     4 from polyfuncs import polsize

     5 

     6 def clcoef(Q, degQ):

     7     """Function to clear zero leading coefficient matrices

     8     of a Polynomial Matrix"""

     9     rQ, cQ = polsize(Q, degQ)

    10     

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

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

    13         degP = 0

    14     else:

    15         P, degP = Q, degQ

    16         rP, cP = rQ, cQ

    17         j = degP

    18         while j>=0:

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

    20                 P = P[:, :j*cP]

    21                 degP = degP-1

    22             else:

    23                 j=0

    24             j -= 1

    25     return P, degP

    26 

    27 if __name__== "__main__":

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

    29            [9, 10, 11, 12, 0, 0, 0, 0],

    30            [5, 6, 7, 8, 0, 0, 0, 0]])"""

    31     t = """degP = 3"""

    32     print s, t

    33     exec(s)

    34     exec(t)

    35     

    36     print clcoef(P, degP)