Fix an incorrect implementation of celu (#21213)
Summary:
Fixing an incorrect implementation of the CELU activation function. The existing implementation works by a chance combination of errors that seem to cancel each other out. This change makes the code more readable, aligns the parameter names correctly, and is consistent with the cuda implementation.
I came across this issue while working on version counters... I attempted to specify a gradient in derivatives.yaml for CELU due to a failed test, but the derivative couldn't be specified correctly without fixing the celu implementation.
https://github.com/pytorch/pytorch/pull/20612
Pull Request resolved: https://github.com/pytorch/pytorch/pull/21213
Differential Revision: D15678823
Pulled By: nairbv
fbshipit-source-id: 29fa76b173a66c2c44ed2e0b7959e77f95d19c43
