Cumulative sum of rainfall

I require cumulative sum of rainfall of 5 days and so. For first 4 days, rainfall will be same as observed on that day, rainfall of 5th day will be sum of first 5 days rainfall, 6th day rainfall will be 2 to 6 day rainfall and son on. Please suggest script for that kind of computation. I have daily rainfall from 1950 to 2013.

Answer 1

[Andrei Bobrov]

Use function of MATLAB - conv2:

R = randi(45,20,1); % Let R - your data of rainfall
out = conv2(R(:),ones(5,1)/5,'same');