dot function

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

Implementation

Tensor<Scalar> dot(Tensor<Vector> a, Tensor<Vector> b) {
  int N = a.data.length;
  double outValue = 0.0;
  for (int i = 0; i < N; i = i + 1) {
    outValue = outValue + (a.data[i] * b.data[i]);
  }
  Tensor<Scalar> out = Tensor<Scalar>(outValue);
  out.creator = Node(
    [a, b],
        () {
      for (int i = 0; i < N; i = i + 1) {
        a.grad[i] = a.grad[i] + out.grad[0] * b.data[i];
        b.grad[i] = b.grad[i] + out.grad[0] * a.data[i];
      }
    },
    opName: 'dot',
    cost: 2 * N,
  );
  return out;
}