class Chainer::Functions::Activation::SigmoidGrad
Logistic sigmoid gradient function.
Public Class Methods
new(inputs)
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# File lib/chainer/functions/activation/sigmoid_grad.rb, line 6 def initialize(inputs) @x, = inputs end
Public Instance Methods
backward(indexes, grad_outputs)
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# File lib/chainer/functions/activation/sigmoid_grad.rb, line 17 def backward(indexes, grad_outputs) y, gy = get_retained_inputs g, = grad_outputs [g * gy * ( 1 -2 * y), g * y * (1 - y)] end
forward(inputs)
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# File lib/chainer/functions/activation/sigmoid_grad.rb, line 10 def forward(inputs) retain_inputs([0, 1]) y, gy = inputs one = 1 [Utils::Array.force_array(gy * y * (one - y))] end