def test_compose(self):
"""Test compose method."""
# Random input test state
rho = DensityMatrix(self.rand_rho(2))
# UnitaryChannel evolution
chan1 = Kraus(self.UX)
chan2 = Kraus(self.UY)
chan = chan1.compose(chan2)
targ = rho @ Kraus(self.UZ)
self.assertEqual(rho @ chan, targ)
# 50% depolarizing channel
chan1 = Kraus(self.depol_kraus(0.5))
chan = chan1.compose(chan1)
targ = rho @ Kraus(self.depol_kraus(0.75))
self.assertEqual(rho @ chan, targ)
# Compose different dimensions
kraus1, kraus2 = self.rand_kraus(2, 4, 4), self.rand_kraus(4, 2, 4)
chan1 = Kraus(kraus1)
chan2 = Kraus(kraus2)
targ = rho @ chan1 @ chan2
chan = chan1.compose(chan2)
self.assertEqual(chan.dim, (2, 2))
self.assertEqual(rho @ chan, targ)
chan = chan1 @ chan2
self.assertEqual(chan.dim, (2, 2))
self.assertEqual(rho @ chan, targ)
def test_compose_front(self):
"""Test front compose method."""
# Random input test state
rho = self.rand_rho(2)
# UnitaryChannel evolution
chan1 = Kraus(self.UX)
chan2 = Kraus(self.UY)
chan = chan1.compose(chan2, front=True)
targ = Kraus(self.UZ)._evolve(rho)
self.assertAllClose(chan._evolve(rho), targ)
# 50% depolarizing channel
chan1 = Kraus(self.depol_kraus(0.5))
chan = chan1.compose(chan1, front=True)
targ = Kraus(self.depol_kraus(0.75))._evolve(rho)
self.assertAllClose(chan._evolve(rho), targ)
# Compose different dimensions
kraus1, kraus2 = self.rand_kraus(2, 4, 4), self.rand_kraus(4, 2, 4)
chan1 = Kraus(kraus1)
chan2 = Kraus(kraus2)
targ = chan2._evolve(chan1._evolve(rho))
chan = chan2.compose(chan1, front=True)
self.assertEqual(chan.dim, (2, 2))
self.assertAllClose(chan._evolve(rho), targ)
def test_compose_inplace(self):
"""Test inplace compose method."""
# Random input test state
rho = self.rand_rho(2)
# UnitaryChannel evolution
chan1 = Kraus(self.matX)
chan2 = Kraus(self.matY)
chan1.compose(chan2, inplace=True)
targ = Kraus(self.matZ)._evolve(rho)
self.assertAllClose(chan1._evolve(rho), targ)
# 50% depolarizing channel
chan = Kraus(self.depol_kraus(0.5))
chan.compose(chan, inplace=True)
targ = Kraus(self.depol_kraus(0.75))._evolve(rho)
self.assertAllClose(chan._evolve(rho), targ)
# Compose different dimensions
kraus1, kraus2 = self.rand_kraus(2, 4, 4), self.rand_kraus(4, 2, 4)
chan1 = Kraus(kraus1)
chan2 = Kraus(kraus2)
targ = chan2._evolve(chan1._evolve(rho))
chan1.compose(chan2, inplace=True)
self.assertEqual(chan1.dims, (2, 2))
self.assertAllClose(chan1._evolve(rho), targ)
chan1 = Kraus(kraus1)
chan2 = Kraus(kraus2)
chan1 @= chan2
self.assertEqual(chan1.dims, (2, 2))
self.assertAllClose(chan1._evolve(rho), targ)