# pylint: skip-file

"""Example of a 6-qubit phase function."""

import revkit

from projectq.cengines import MainEngine

from projectq.libs.revkit import PermutationOracle, PhaseOracle

from projectq.meta import Compute, Dagger, Uncompute

from projectq.ops import All, H, Measure, X

# phase function

def f(a, b, c, d, e, f):

"""Phase function."""

return (a and b) ^ (c and d) ^ (e and f)

# permutation

pi = [0, 2, 3, 5, 7, 1, 4, 6]

eng = MainEngine()

qubits = eng.allocate_qureg(6)

x = qubits[::2] # qubits on odd lines

y = qubits[1::2] # qubits on even lines

# circuit

with Compute(eng):

All(H) | qubits

All(X) | [x[0], x[1]]

PermutationOracle(pi) | y

PhaseOracle(f) | qubits

Uncompute(eng)

with Compute(eng):

with Dagger(eng):

PermutationOracle(pi, synth=revkit.dbs) | x

PhaseOracle(f) | qubits

Uncompute(eng)

All(H) | qubits

All(Measure) | qubits

# measurement result

print(f"Shift is {sum(int(q) << i for i, q in enumerate(qubits))}")