def test_compose_front(self):
"""Test deprecated front compose method."""
# Random input test state
rho_init = DensityMatrix(self.rand_rho(2))
# UnitaryChannel evolution
chan1 = Stinespring(self.UX)
chan2 = Stinespring(self.UY)
chan = chan1.compose(chan2, front=True)
rho_targ = rho_init @ Stinespring(self.UZ)
self.assertEqual(rho_init.evolve(chan), rho_targ)
# 50% depolarizing channel
chan1 = Stinespring(self.depol_stine(0.5))
chan = chan1.compose(chan1, front=True)
rho_targ = rho_init @ Stinespring(self.depol_stine(0.75))
self.assertEqual(rho_init.evolve(chan), rho_targ)
# Compose different dimensions
stine1, stine2 = self.rand_matrix(16, 2), self.rand_matrix(8, 4)
chan1 = Stinespring(stine1, input_dims=2, output_dims=4)
chan2 = Stinespring(stine2, input_dims=4, output_dims=2)
rho_targ = rho_init @ chan1 @ chan2
chan = chan2.compose(chan1, front=True)
self.assertEqual(chan.dim, (2, 2))
self.assertEqual(rho_init.evolve(chan), rho_targ)
def test_compose_front(self):
"""Test front compose method."""
# Random input test state
rho = self.rand_rho(2)
# UnitaryChannel evolution
chan1 = Stinespring(self.matX)
chan2 = Stinespring(self.matY)
chan = chan1.compose(chan2, front=True)
targ = Stinespring(self.matZ)._evolve(rho)
self.assertAllClose(chan._evolve(rho), targ)
# 50% depolarizing channel
chan1 = Stinespring(self.depol_stine(0.5))
chan = chan1.compose(chan1, front=True)
targ = Stinespring(self.depol_stine(0.75))._evolve(rho)
self.assertAllClose(chan._evolve(rho), targ)
# Compose different dimensions
stine1, stine2 = self.rand_matrix(16, 2), self.rand_matrix(8, 4)
chan1 = Stinespring(stine1, input_dim=2, output_dim=4)
chan2 = Stinespring(stine2, input_dim=4, output_dim=2)
targ = chan2._evolve(chan1._evolve(rho))
chan = chan2.compose(chan1, front=True)
self.assertEqual(chan.dims, (2, 2))
self.assertAllClose(chan._evolve(rho), targ)
