def test_no_touch_single_sqrt_iswap_inv():
a, b = cirq.LineQubit.range(2)
assert_optimizes(
use_sqrt_iswap_inv=True,
before=cirq.Circuit([
cirq.Moment([cirq.SQRT_ISWAP_INV(a, b).with_tags('mytag')]),
]),
expected=cirq.Circuit([
cirq.Moment([cirq.SQRT_ISWAP_INV(a, b).with_tags('mytag')]),
]),
)
def cphase_symbols_to_sqrt_iswap(a, b, turns):
"""Version of cphase_to_sqrt_iswap that works with symbols.
Note that the formulae contained below will need to be flattened
into a sweep before serializing.
"""
theta = sympy.Mod(turns, 2.0) * sympy.pi
# -1 if theta > pi. Adds a hacky fudge factor so theta=pi is not 0
sign = sympy.sign(sympy.pi - theta + 1e-9)
# For sign = 1: theta. For sign = -1, 2pi-theta
theta_prime = (sympy.pi - sign * sympy.pi) + sign * theta
phi = sympy.asin(np.sqrt(2) * sympy.sin(theta_prime / 4))
xi = sympy.atan(sympy.tan(phi) / np.sqrt(2))
yield cirq.rz(sign * 0.5 * theta_prime).on(a)
yield cirq.rz(sign * 0.5 * theta_prime).on(b)
yield cirq.rx(xi).on(a)
yield cirq.X(b)**(-sign * 0.5)
yield cirq.SQRT_ISWAP_INV(a, b)
yield cirq.rx(-2 * phi).on(a)
yield cirq.SQRT_ISWAP(a, b)
yield cirq.rx(xi).on(a)
yield cirq.X(b)**(sign * 0.5)
def test_optimizes_single_inv_sqrt_iswap_require3():
a, b = cirq.LineQubit.range(2)
c = cirq.Circuit(cirq.SQRT_ISWAP_INV(a, b))
assert_optimization_not_broken(c, required_sqrt_iswap_count=3)
c = cirq.optimize_for_target_gateset(
c, gateset=cirq.SqrtIswapTargetGateset(required_sqrt_iswap_count=3))
assert len([1 for op in c.all_operations() if len(op.qubits) == 2]) == 3
def test_optimizes_single_inv_sqrt_iswap_require3():
a, b = cirq.LineQubit.range(2)
c = cirq.Circuit(cirq.SQRT_ISWAP_INV(a, b))
assert_optimization_not_broken(c, required_sqrt_iswap_count=3)
cirq.MergeInteractionsToSqrtIswap(
required_sqrt_iswap_count=3).optimize_circuit(c)
assert len([1 for op in c.all_operations() if len(op.qubits) == 2]) == 3
def test_optimizes_single_iswap_require2():
a, b = cirq.LineQubit.range(2)
c = cirq.Circuit(cirq.SQRT_ISWAP_INV(a, b)) # Minimum 1 sqrt-iSWAP but 2 possible
assert_optimization_not_broken(c, required_sqrt_iswap_count=2)
c = cirq.optimize_for_target_gateset(
c, gateset=cirq.SqrtIswapTargetGateset(required_sqrt_iswap_count=2), ignore_failures=False
)
assert len([1 for op in c.all_operations() if len(op.qubits) == 2]) == 2
def test_optimizes_single_inv_sqrt_iswap():
a, b = cirq.LineQubit.range(2)
c = cirq.Circuit(cirq.SQRT_ISWAP_INV(a, b))
assert_optimization_not_broken(c)
c = cirq.optimize_for_target_gateset(
c, gateset=cirq.SqrtIswapTargetGateset(), ignore_failures=False
)
assert len([1 for op in c.all_operations() if len(op.qubits) == 2]) == 1
def test_simplifies_sqrt_iswap_inv():
a, b = cirq.LineQubit.range(2)
assert_optimizes(
use_sqrt_iswap_inv=True,
before=cirq.Circuit([
# SQRT_ISWAP**8 == Identity
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP_INV(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
cirq.Moment([cirq.SQRT_ISWAP(a, b)]),
]),
expected=cirq.Circuit([cirq.Moment([cirq.SQRT_ISWAP_INV(a, b)])]),
)
def test_optimizes_single_inv_sqrt_iswap():
a, b = cirq.LineQubit.range(2)
c = cirq.Circuit(cirq.SQRT_ISWAP_INV(a, b))
assert_optimization_not_broken(c)
with cirq.testing.assert_deprecated("Use cirq.optimize_for_target_gateset",
deadline='v1.0',
count=2):
cirq.MergeInteractionsToSqrtIswap().optimize_circuit(c)
assert len([1 for op in c.all_operations() if len(op.qubits) == 2]) == 1
def test_works_with_tags():
a, b = cirq.LineQubit.range(2)
assert_optimizes(
before=cirq.Circuit([
cirq.Moment([cirq.SQRT_ISWAP(a, b).with_tags('mytag1')]),
cirq.Moment([cirq.SQRT_ISWAP(a, b).with_tags('mytag2')]),
cirq.Moment([cirq.SQRT_ISWAP_INV(a, b).with_tags('mytag3')]),
]),
expected=cirq.Circuit([cirq.Moment([cirq.SQRT_ISWAP(a, b)])]),
)
def iswap_to_sqrt_iswap(a, b, turns):
"""Implement the evolution of the hopping term using two sqrt_iswap gates
and single-qubit operations. Output unitary:
[1 0 0 0],
[0 c is 0],
[0 is c 0],
[0 0 0 1],
where c = cos(t * np.pi / 2) and s = sin(t * np.pi / 2).
Args:
a: the first qubit
b: the second qubit
turns: Exponent that specifies the evolution time in number of rotations.
"""
yield cirq.Z(a)**0.75
yield cirq.Z(b)**0.25
yield cirq.SQRT_ISWAP_INV(a, b)
yield cirq.Z(a)**(-turns / 2 + 1)
yield cirq.Z(b)**(turns / 2)
yield cirq.SQRT_ISWAP_INV(a, b)
yield cirq.Z(a)**0.25
yield cirq.Z(b)**-0.25
def cphase_to_sqrt_iswap(a, b, turns):
"""Implement a C-Phase gate using two sqrt ISWAP gates and single-qubit
operations. The circuit is equivalent to cirq.CZPowGate(exponent=turns).
Output unitary:
[1 0 0 0],
[0 1 0 0],
[0 0 1 0],
[0 0 0 e^{i turns pi}].
Args:
a: the first qubit
b: the second qubit
turns: Exponent specifying the evolution time in number of rotations.
"""
theta = (turns % 2) * np.pi
if 0 <= theta <= np.pi:
sign = 1.0
theta_prime = theta
elif np.pi < theta < 2 * np.pi:
sign = -1.0
theta_prime = 2 * np.pi - theta
if np.isclose(theta, np.pi):
# If we are close to pi, just set values manually to avoid possible
# numerical errors with arcsin of greater than 1.0 (Ahem, Windows).
phi = np.pi / 2
xi = np.pi / 2
else:
phi = np.arcsin(np.sqrt(2) * np.sin(theta_prime / 4))
xi = np.arctan(np.tan(phi) / np.sqrt(2))
yield cirq.rz(sign * 0.5 * theta_prime).on(a)
yield cirq.rz(sign * 0.5 * theta_prime).on(b)
yield cirq.rx(xi).on(a)
yield cirq.X(b)**(-sign * 0.5)
yield cirq.SQRT_ISWAP_INV(a, b)
yield cirq.rx(-2 * phi).on(a)
yield cirq.SQRT_ISWAP(a, b)
yield cirq.rx(xi).on(a)
yield cirq.X(b)**(sign * 0.5)
# Corrects global phase
yield cirq.global_phase_operation(np.exp(sign * theta_prime * 0.25j))
