sigmoid function

Tensor<Vector> sigmoid(
  1. Tensor<Vector> v
)

Implementation

Tensor<Vector> sigmoid(Tensor<Vector> v) {
  int N = v.value.length;
  Vector outValue = [];
  for (int i = 0; i < N; i++) {
    outValue.add(1.0 / (1.0 + exp(-v.value[i])));
  }
  Tensor<Vector> out = Tensor<Vector>(outValue);
  out.creator = Node(
    [v],
    () {
      for (int i = 0; i < v.value.length; i++) {
        v.grad[i] += out.grad[i] * (out.value[i] * (1 - out.value[i]));
      }
    },
    opName: 'sigmoid_vector', // <-- Renamed for clarity
    cost: N,
  );
  return out;
}