3 ms·
I don't think this is right. An autodiff package will likely report +inf for the derivative of cuberoot at 0. The problem is really that there are a lot of way
by gugagore 7y ago
I don't think this is right. An autodiff package will likely report +inf for the derivative of cuberoot at 0.
The problem is really that there are a lot of ways the function can have infinite slope. The sqrt function also has infinite slope at 0.
Dividing by zero isn't where the NaN comes from.
- deleted 7y ago[deleted]
- tobmlt 7y agoMy mistake then. I did not intend to try and be so precise. I was thinking loosely. I have a very simple autodiff tool hand rolled (in Python) here to play with. I raise 0 to a negative exponent in the gradient of the cube root at 0. I do not get a NAN. Strictly speaking I get this: "ZeroDivisionError: 0.0 cannot be raised to a negative power" Is that satisfying? I do not claim anything more specific here. Sorry to be imprecise.
- deleted 7y ago[deleted]