What are practical uses for STL's 'partial_sum'?

Question

What/where are the practical uses of the partial_sum algorithm in STL?

What are some other interesting/non-trivial examples or use-cases?

Answer 1

Last time I (would have) used it is when converting a discrete probability distribution (an array of p(X = k)) into a cumulative distribution (an array of p(X <= k)). To select once from the distribution, you can pick a number from [0-1) randomly, then binary search into the cumulative distribution.

That code wasn't in C++, though, so I did the partial sum myself.