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Keeping randn in TwoQubitWeylDecomposition but seeded (#3653) 

* seeding randn

* use np.random.RandomState

* i

* cleaning up

* test case

* Update test/python/quantum_info/test_synthesis.py

Co-Authored-By: Ali Javadi-Abhari <ajavadia@users.noreply.github.com>

* Update qiskit/quantum_info/synthesis/two_qubit_decompose.py

Co-authored-by: Ali Javadi-Abhari <ajavadia@users.noreply.github.com>
This commit is contained in:
Luciano Bello 2019-12-28 20:44:07 -05:00 committed by Ali Javadi-Abhari
parent 5dd98aac56
commit 2d75ea7b46
2 changed files with 9 additions and 2 deletions
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5
qiskit/quantum_info/synthesis/two_qubit_decompose.py
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@ -161,8 +161,9 @@ class TwoQubitWeylDecomposition:
# M2 is a symmetric complex matrix. We need to decompose it as M2 = P D P^T where
# P ∈ SO(4), D is diagonal with unit-magnitude elements.
# D, P = la.eig(M2) # this can fail for certain kinds of degeneracy
for _ in range(100): # FIXME: this randomized algorithm is horrendous
M2real = np.random.randn()*M2.real + np.random.randn()*M2.imag
for i in range(100): # FIXME: this randomized algorithm is horrendous
state = np.random.RandomState(i)
M2real = state.randn()*M2.real + state.randn()*M2.imag
_, P = la.eigh(M2real)
D = P.T.dot(M2).dot(P).diagonal()
if np.allclose(P.dot(np.diag(D)).dot(P.T), M2, rtol=1.0e-13, atol=1.0e-13):

6
test/python/quantum_info/test_synthesis.py
View File

@ -542,6 +542,12 @@ class TestTwoQubitDecomposeExact(QiskitTestCase):
U = execute(qc, sim).result().get_unitary()
self.assertEqual(two_qubit_cnot_decompose.num_basis_gates(U), 3)
def test_seed_289(self):
"""This specific case failed when PR #3585 was applied
See https://github.com/Qiskit/qiskit-terra/pull/3652"""
unitary = random_unitary(4, seed=289)
self.check_exact_decomposition(unitary.data, two_qubit_cnot_decompose)
# FIXME: need to write tests for the approximate decompositions