chainerx.sigmoid_cross_entropy

chainerx.sigmoid_cross_entropy(x1, x2)

Element-wise cross entropy loss for pre-sigmoid activations.

Parameters

  • x1 (ndarray) – An array whose (i, j)-th element indicates the unnormalized log probability of the j-th unit at the i-th example.

  • x2 (ndarray) – An array whose (i, j)-th element indicates a signed integer vector of ground truth labels 0 or 1. If x2[i, j] == -1, corresponding x1[i, j] is ignored. Loss is zero if all ground truth labels are -1.

Returns

An array of the cross entropy.

Return type

ndarray

Note

During backpropagation, this function propagates the gradient of the output array to the input array x1 only.