Tamas, try scanl (+) 0 for the cumulative sum

From there the zipWith idea you mentioned seems like the way to go.

-Chad

Hi,

I have two lists, p and lambda (both are finite). I would like to calculate

1) the cumulative sum of lambda, ie if

lambda = [lambda1,lambda2,lambda3,...]

then

csum lambda = [lambda1,lambda1+lambda2,lambda1+lambda2+lambda3,...]

2) the cumulative sum of p*lambda (multiplication elementwise)

Once I know how to do the first, I know how to do the second I guess (doing the multiplication using zipWith to get the p*lambda list, but I would be interested in any other suggestions). Currently I take and sum, but then I am calculating the same sums many times.

Thanks,

Tamas