dot function

Tensor<Scalar> dot(Tensor<Vector> a, Tensor<Vector> b)

Implementation

Tensor<Scalar> dot(Tensor<Vector> a, Tensor<Vector> b) {
  int N = a.value.length;
  Scalar outValue = 0.0;
  for (int i = 0; i < N; i++) {
    outValue += a.value[i] * b.value[i];
  }
  Tensor<Scalar> out = Tensor<Scalar>(outValue);
  out.creator = Node(
    [a, b],
    () {
      for (int i = 0; i < a.value.length; i++) {
        a.grad[i] += out.grad * b.value[i];
        b.grad[i] += out.grad * a.value[i];
      }
    },
    opName: 'dot', // This name is already unique
    cost: 2 * N,
  );
  return out;
}