[Numpy-discussion] Familiar w/ reduce ?

[Pierre GM]

All,
I have a (m_1+1,m_2+1) matrix of 0 and 1, and I need to compute a second 
matrix U by recurrence.
A double-loop as such
#............................
U = empty((m_1+1, m_2+1))
U[:,0] = C[:,0]
U[0,:] = C[0,:]
for i in range(1,m_1+1):
    for j in range(1,m_2+1):
        U[i,j] = C[i,j] * (U[i,j-1] + U[i-1,j])
#............................
does the trick, but I suspect there is not a simpler, more elegant solution. 
Would anybody have any idea ?
Thanks a lot in advance, and all my apologies for being a tad lazy...

(PS: FYI, it's for a reimplementation of the Kolmogorov-Smirnov test 
statistic, where ties occur)

P.