FWIW, I sketched a little histogram Combiner:
Very simple; nothing fancy. Probably several of these lurking around.
Explanation and example in the code. Look okay?
I'll put together some test cases soon. I've also got a discrete value
histogram Combiner that I'll put on github.
Please lemme know if you have suggestions or corrections.
Keith Turner 2013-06-27, 13:29