#!/usr/bin/python

# given A and B arrays, returns C = [<-A-> 0

#                                    0  <-B->] with B shifted east by N cols

import pylab as pl

from scipy import signal

def seshft(A, B, N):

    Arows, Acols = pl.atleast_2d(A).shape

    Brows, Bcols = pl.atleast_2d(B).shape

    if N>=0:

        n = Arows+Brows

        m = max(Acols, Bcols+N)

        C = pl.zeros((n, m))

        C[:Arows, :Acols] = A

        C[Arows:, N:N+Bcols] = B

    else:

        N = -N

        n = Arows+Brows

        m = max(Acols+N, Bcols)

        C = pl.zeros((n, m))

        C[:Arows, N:N+Arows] = A

        C[Arows:, :Bcols] = B

    return C

if __name__== "__main__":

    a = "A = pl.eye(3)"

    b = "B = pl.eye(10)"

    n = "N = 0"

    exec(a)

    exec(b)

    exec(n)

    print a, b, n

    C = seshft(A, B, N)

    print C