XOR Re-upload Classifier

module xor_classifier;
@seed(17);
param w: Angle = 0.4;
fn main() {
  let q = qreg[2];
  encode(sample_row(), q, method: "reupload");
  CNOT(q[0], q[1]);
  Ry(q[1], w);
  let cost = expect Z(q[1]);
  train {
    objective: minimize cost;
    optimizer: adam(lr = 0.2);
    steps: 40;
    dataset: xor_2d;
    loss: mse;
  }
  return cost;
}