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swap2cz_decomposer

SWAP2CZDecomposer

Bases: Decomposer

Predefined decomposition of SWAP gate to Ry rotations and 3 CZ gates. ---x--- -------------•-[Ry(-pi/2)]-•-[Ry(+pi/2)]-•------------- | → | | | ---x--- -[Ry(-pi/2)]-•-[Ry(+pi/2)]-•-[Ry(-pi/2)]-•-[Ry(+pi/2)]- Note: This decomposition preserves the global phase of the SWAP gate.

Source code in opensquirrel/passes/decomposer/swap2cz_decomposer.py 
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class SWAP2CZDecomposer(Decomposer):
    """Predefined decomposition of SWAP gate to Ry rotations and 3 CZ gates.
    ---x---     -------------•-[Ry(-pi/2)]-•-[Ry(+pi/2)]-•-------------
       |     →               |             |             |
    ---x---     -[Ry(-pi/2)]-•-[Ry(+pi/2)]-•-[Ry(-pi/2)]-•-[Ry(+pi/2)]-
    Note:
        This decomposition preserves the global phase of the SWAP gate.
    """

    def decompose(self, gate: Gate) -> list[Gate]:
        if gate.name != "SWAP":
            return [gate]
        qubit0, qubit1 = gate.get_qubit_operands()
        return [
            Ry(qubit1, -pi / 2),
            CZ(qubit0, qubit1),
            Ry(qubit1, pi / 2),
            Ry(qubit0, -pi / 2),
            CZ(qubit1, qubit0),
            Ry(qubit0, pi / 2),
            Ry(qubit1, -pi / 2),
            CZ(qubit0, qubit1),
            Ry(qubit1, pi / 2),
        ]