def compile_ry(gate: RotationGateImpl,
controlled_rotation: bool = False) -> QCircuit:
"""
Compile Ry gates into Rx and Rz.
Parameters
----------
gate:
the gate.
controlled_rotation:
determines if the decomposition of the controlled-Ry gate will be performed in compile_controlled_rotation,
if not, decomposition will be performed here
Returns
-------
QCircuit, the result of compilation.
"""
if gate.name.lower() == "ry":
if not (gate.is_controlled() and controlled_rotation):
return Rz(target=gate.target, control=None, angle=-numpy.pi / 2) \
+ Rx(target=gate.target, control=gate.control, angle=gate.parameter) \
+ Rz(target=gate.target, control=None, angle=numpy.pi / 2)
return QCircuit.wrap_gate(gate)
def compile_controlled_rotation(gate: RotationGateImpl,
angles: list = None) -> QCircuit:
"""
Recompilation of a controlled-rotation gate
Basis change into Rz then recompilation of controled Rz, then change basis back
:param gate: The rotational gate
:param angles: new angles to set, given as a list of two. If None the angle in the gate is used (default)
:return: set of gates wrapped in QCircuit class
"""
if not gate.is_controlled():
return QCircuit.wrap_gate(gate)
if not isinstance(gate, RotationGateImpl):
return QCircuit.wrap_gate(gate)
if angles is None:
angles = [gate.parameter / 2, -gate.parameter / 2]
if len(gate.target) > 1:
return compile_controlled_rotation(gate=compile_multitarget(gate=gate),
angles=angles)
target = gate.target
control = gate.control
result = QCircuit()
result += change_basis(target=target, axis=gate._axis)
result += RotationGateImpl(axis="z", target=target, angle=angles[0])
result += QGateImpl(name="X", target=target, control=control)
result += RotationGateImpl(axis="Z", target=target, angle=angles[1])
result += QGateImpl(name="X", target=target, control=control)
result += change_basis(target=target, axis=gate._axis, daggered=True)
result.n_qubits = result.max_qubit() + 1
return result
def compile_controlled_rotation(gate: RotationGateImpl) -> QCircuit:
"""
Recompilation of a controlled-rotation gate
Basis change into Rz then recompilation of controled Rz, then change basis back
:param gate: The rotational gate
:return: set of gates wrapped in QCircuit class
"""
if not gate.is_controlled():
return QCircuit.wrap_gate(gate)
if not isinstance(gate, RotationGateImpl):
return QCircuit.wrap_gate(gate)
if len(gate.target) > 1:
return compile_controlled_rotation(gate=compile_multitarget(gate=gate))
target = gate.target
control = gate.control
k = len(control)
cind = _pattern(k) + [k - 1]
result = QCircuit()
result += change_basis(target=target, axis=gate._axis)
coeff = -1 / pow(2, k)
for i, ci in enumerate(cind):
coeff *= -1
result += Rz(target=target, angle=coeff * gate.parameter)
result += CNOT(control[ci], target)
result += change_basis(target=target, axis=gate._axis, daggered=True)
result.n_qubits = result.max_qubit() + 1
return result