def test_equiv(self):
"""Test equiv method"""
vec = np.array([1, 0, 0, -1j]) / np.sqrt(2)
phase = np.exp(-1j * np.pi / 4)
statevec = Statevector(vec)
self.assertTrue(statevec.equiv(phase * vec))
self.assertTrue(statevec.equiv(Statevector(phase * vec)))
self.assertFalse(statevec.equiv(2 * vec))
def test_equiv_on_circuit(self):
"""Test the equiv method on different types of input."""
statevec = Statevector([1, 0])
qc = QuantumCircuit(1)
self.assertTrue(statevec.equiv(qc))
qc.x(0)
self.assertFalse(statevec.equiv(qc))
def test_densitymatrix_to_statevector_pure(self):
"""Test converting a pure density matrix to statevector."""
state = 1 / np.sqrt(2) * (np.array([1, 0, 0, 0, 0, 0, 0, 1]))
psi = Statevector(state)
rho = DensityMatrix(psi)
phi = rho.to_statevector()
self.assertTrue(psi.equiv(phi))