Matlab cumsum reset at NaN?

Question

If I have a vector of either 1\'s or NaN\'s like this:

[1 1 1 NaN 1 1 NaN 1 1 1 1]

How can I reset the cumsum to zero at the location of th

Answer 1

You can try the following two 'vectorized' lines:

A(isnan(A)) = 1-diff([0 find(isnan(A))]);
cumsum(A)

ans =

  1     2     3     0     1     2     0     1     2     3     4

The trick is to substitute NaN with a value that will reset cumsum to 0 at those points.