multiply along

~EDITED'

Hi there, I have a long matrix 1000 x 34 want to do the cumulative multiplication left to right to give a 1000 x 1 matrix then the sum of the multiplication going downwards. So like a sum function but multiplying each element going sideways then downwards.

EDITED THIS ANSWER HAS BEEN ANSWERED but need a follow on answer...

Answer 1

[Oleg Komarov]

sum(cumprod(A))

[Mate 2u]

What if their are zeros. Is there a line code to change all zeros to 1s?

[Walter Roberson]

T = A;

T(T==0) = 1;

sum(cumprod(T))

Answer 2

[Walter Roberson]

If the numbers are strictly positive, you could log() and cumsum() and exp() the result.