From 4c4f6bd43b2c8be919d6e86303987175d2c972fe Mon Sep 17 00:00:00 2001 From: Daniel Tsvetkov Date: Mon, 3 Feb 2020 16:15:00 +0100 Subject: [PATCH] cnot is generalized to two qubit gate --- lib_q_computer_math.py | 68 ++++++++++++++---------------------------- 1 file changed, 23 insertions(+), 45 deletions(-) diff --git a/lib_q_computer_math.py b/lib_q_computer_math.py index 689d9e1..ee8e28c 100644 --- a/lib_q_computer_math.py +++ b/lib_q_computer_math.py @@ -428,8 +428,8 @@ class HermitianOperator(LinearOperator, HermitianMatrix): return str(self.m) -# TODO - How to add a CNOT gate to the Quantum Processor? -# Imagine if I have to act on a 3-qubit computer and CNOT(q1, q3) +# How to add a CNOT gate to the Quantum Processor? +# Imagine if I have to act on a 3-qubit computer and CNOT(q1, q3) # # Decomposed CNOT : # reverse engineered from @@ -454,8 +454,8 @@ class TwoQubitPartial(object): return str("-{}-".format(self.rpr)) -C_ = TwoQubitPartial("C") -x_ = TwoQubitPartial("x") +C_partial = TwoQubitPartial("C") +x_partial = TwoQubitPartial("x") class TwoQubitOperator(UnitaryOperator): @@ -468,13 +468,16 @@ class TwoQubitOperator(UnitaryOperator): self.A_p = A_p self.B_p = B_p + A.operator = self + B.operator = self + def verify_step(self, step): if not (step.count(self.A) == 1 and step.count(self.B) == 1): - raise RuntimeError("Both CONTROL and TARGET need to be defined in the same step exactly once") + raise RuntimeError("Both {} and {} need to be defined in the same step exactly once".format( + self.A, self.B + )) def compose(self, step, state): - # TODO: Hacky way to do CNOT - # Should generalize for a 2-Qubit gate # _0.x(_0) * Matrix(I.m) + _1.x(_1) * Matrix(X.m) outer_0, outer_1 = [], [] for s in step: @@ -555,11 +558,12 @@ Z = UnitaryOperator([[1, 0], name="Z") -# TODO: These are rotations that are specified commonly e.g. in +# These are rotations that are specified commonly e.g. in # https://www.quantum-inspire.com/kbase/rotation-operators/ # http://www.vcpc.univie.ac.at/~ian/hotlist/qc/talks/bloch-sphere-rotations.pdf # and elsewhere DO NOT equate X, Y and Z for theta=np.pi -# ?????????????????????????????????????????????????????? +# However - they are correct up to a global phase which is all that matters for measurement purposes +# def Rx(theta): return UnitaryOperator([[np.cos(theta / 2), -1j * np.sin(theta / 2)], @@ -578,11 +582,6 @@ def Rz(theta): [0, np.power(np.e, 1j * theta / 2)]], name="Rz") - -# def unitary(alpha, vector:Vector, theta): -# return np.exp(1j * alpha) - - H = UnitaryOperator([[1 / np.sqrt(2), 1 / np.sqrt(2)], [1 / np.sqrt(2), -1 / np.sqrt(2)], ], name="H") @@ -591,16 +590,7 @@ CNOT = TwoQubitOperator([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 0, 1], [0, 0, 1, 0], ], - TwoQubitPartial("C"), - TwoQubitPartial("x"), - I, - X) - -C, x = CNOT.A, CNOT.B - - -# TODO: End Hacky way to define 2-qbit gate -########################################################### + C_partial, x_partial, I, X) def assert_raises(exception, msg, callable, *args, **kwargs): @@ -664,7 +654,7 @@ class MeasurementOpeartor(HermitianOperator): def get_prob(self, state: State): state_ct = state.conjugate_transpose() - return np.asscalar(state_ct.m.dot(self.m.dot(state.m))) + return state_ct.m.dot(self.m.dot(state.m)).item() def test_measurement_ops(): @@ -939,24 +929,12 @@ class QuantumCircuit(object): self.add_row(row_data) def compose_quantum_state(self, step): - if C in step or x in step: - if not (step.count(C) == 1 and step.count(x) == 1): - raise RuntimeError("Both CONTROL and TARGET need to be defined in the same step exactly once") - # TODO: Hacky way to do CNOT - # Should generalize for a 2-Qubit gate - # _0.x(_0) * Matrix(I.m) + _1.x(_1) * Matrix(X.m) - outer_0, outer_1 = [], [] - for s in step: - if s == C: - outer_0.append(_0.x(_0)) - outer_1.append(_1.x(_1)) - elif s == x: - outer_0.append(Matrix(I.m)) - outer_1.append(Matrix(X.m)) - else: - outer_0.append(Matrix(s.m)) - outer_1.append(Matrix(s.m)) - return reduce((lambda x, y: x * y), outer_0) + reduce((lambda x, y: x * y), outer_1) + partials = [op for op in step if isinstance(op, TwoQubitPartial)] + # TODO: No more than 1 TwoQubitGate **OR** UnitaryOperator can be used in a step + for partial in partials: + two_qubit_op = partial.operator + two_qubit_op.verify_step() + return two_qubit_op.compose(step) return reduce((lambda x, y: x * y), step) def step(self): @@ -1077,9 +1055,9 @@ class QuantumProcessor(object): def test_quantum_processor(): # Produce Bell state between 0 and 2 qubit qc = QuantumCircuit(3) - qc.add_row([H, C]) + qc.add_row([H, C_partial]) qc.add_row([_, _]) - qc.add_row([_, x]) + qc.add_row([_, x_partial]) qc.print() qp = QuantumProcessor(qc) qp.get_sample(100)