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#-------------------------------------------------------------
/*
* Tanh nonlinearity layer.
*/
source("nn/layers/sigmoid.dml") as sigmoid
forward = function(matrix[double] X)
return (matrix[double] out) {
/*
* Computes the forward pass for a tanh nonlinearity layer.
*
* ```
* tanh(x) = (e^x - e^-x) / (e^x + e^-x)
* ```
*
* Inputs:
* - X: Inputs, of shape (any, any).
*
* Outputs:
* - out: Outputs, of same shape as `X`.
*/
out = tanh(X)
}
backward = function(matrix[double] dout, matrix[double] X)
return (matrix[double] dX) {
/*
* Computes the backward pass for a tanh nonlinearity layer.
*
* Inputs:
* - dout: Gradient wrt `out` from upstream, of same shape as `X`.
* - X: Inputs, of shape (any, any).
*
* Outputs:
* - dX: Gradient wrt `X`, of same shape as `X`.
*/
out = tanh(X)
dX = (1-out^2) * dout
}