def two_mode_squeeze(r, theta, trunc):
r"""The two-mode squeezing operator :math:`S_2(re^{i\theta})`.
Args:
r (float): two-mode squeezing magnitude
theta (float): two-mode squeezing phase
trunc (int): Fock ladder cutoff
"""
ret = two_mode_squeezing_tw(r, theta, cutoff=trunc)
# Transpose needed because of different conventions in SF and The Walrus.
ret = np.transpose(ret, [0, 2, 1, 3])
return ret
def single_two_mode_squeezing_matrix(theta, phi, cutoff, dtype=def_type.as_numpy_dtype):
"""creates a single mode two-mode squeezing matrix"""
theta = theta.numpy()
phi = phi.numpy()
gate = two_mode_squeezing_tw(theta, phi, cutoff, dtype)
gate = np.transpose(gate, [0, 2, 1, 3])
def grad(dy):
Dr, Dphi = grad_two_mode_squeezing_tw(np.transpose(gate, [0, 2, 1, 3]), theta, phi)
Dr = np.transpose(Dr, [0, 2, 1, 3])
Dphi = np.transpose(Dphi, [0, 2, 1, 3])
grad_r = tf.math.real(tf.reduce_sum(dy * tf.math.conj(Dr)))
grad_phi = tf.math.real(tf.reduce_sum(dy * tf.math.conj(Dphi)))
return grad_r, grad_phi, None
return gate, grad