Proposed new feature or change:

Mailing list post

Add a reverse argument to accumulating functions that, when true, causes the accumulation to be performed in reverse. Examples:

• ufunc.accumulate
• cumsum
• nancumsum
• cumprod
• nancumprod

Currently, this can be done via two flips, before and after the operation. But it might be more efficient to do it directly at the low level.