Re: [Numpy-discussion] nonuniform scatter operations

2008/9/28 Geoffrey Irving <irving@naml.us>:

Is there an efficient way to implement a nonuniform gather operation in numpy? Specifically, I want to do something like

n,m = 100,1000 X = random.uniform(size=n) K = random.randint(n, size=m) Y = random.uniform(size=m)

for k,y in zip(K,Y): X[k] += y

but I want it to be fast. The naive attempt "X[K] += Y" does not work, since the slice assumes the indices don't repeat.

I believe histogram can be persuaded to do this. Anne