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MCRWithoutAux

QuICT.core.gate.backend.MCRWithoutAux 

MCRWithoutAux(num_ctrl: int, theta: float, targ_rot_mode: str = 'ry', ctrl_rot_mode: str = 'ry', reset_ctrl: bool = True, name: str = None)

Bases: CompositeGate

A Multi control rotation gate.

References

Linear-Depth Quantum Circuits for n-qubit Toffoli gates with no Ancilla https://arxiv.org/abs/1303.3557

Construct a multi-controlled rotation gate currently support ry and rz to be controlled.

Parameters:

  • num_ctrl (int) –

    the number of control bit.

  • theta (float) –

    the angle for the rotation.

  • targ_rot_mode (str, default: 'ry' ) –

    rotation gate to be applied on the target qubit.

  • ctrl_rot_mode (str, default: 'ry' ) –

    rotation gate to be applied on the contrl qubit.

  • reset_ctrl (bool, default: True ) –

    If True the control bits will be reset to original states after the target rotation is applied.

Source code in QuICT/core/gate/backend/mcrot/mcr_without_aux.py 
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def __init__(
    self,
    num_ctrl: int,
    theta: float,
    targ_rot_mode: str = "ry",
    ctrl_rot_mode: str = "ry",
    reset_ctrl: bool = True,
    name: str = None
):
    """ Construct a multi-controlled rotation gate currently support ry and rz to be controlled.

    Args:
        num_ctrl (int): the number of control bit.
        theta (float): the angle for the rotation.
        targ_rot_mode (str): rotation gate to be applied on the target qubit.
        ctrl_rot_mode (str): rotation gate to be applied on the contrl qubit.
        reset_ctrl (bool): If `True` the control bits will be reset to original states after the
            target rotation is applied.
    """
    if num_ctrl < 0:
        raise ValueError(f"num_ctrl requires to be non-negative but given {num_ctrl}")
    targ_rot_map = {"ry": CRy, "rz": CRz, "u1": CU1}
    ctrl_rot_map = {"ry": CRy}
    if targ_rot_mode not in targ_rot_map:
        raise ValueError(f"targ_rot_mode requires to be in {list(targ_rot_map.keys())} but given {targ_rot_mode}")
    if ctrl_rot_mode not in ctrl_rot_map:
        raise ValueError(f"ctrl_rot_mode requires to be in {list(ctrl_rot_map.keys())} but given {ctrl_rot_mode}")

    # ctrl_rot = self._crx
    R_targ = targ_rot_map[targ_rot_mode]
    R_ctrl = ctrl_rot_map[ctrl_rot_mode]

    super().__init__(name)
    if num_ctrl == 0:
        if targ_rot_mode == "ry":
            Ry(theta) | self(0)
        elif targ_rot_mode == "rz":
            Rz(theta) | self(0)
        elif targ_rot_mode == "u1":
            U1(theta) | self(0)
        return

    if num_ctrl == 1:
        R_targ(theta) | self([0, 1])
        return

    for ctrl in reversed(range(1, num_ctrl)):
        R_targ(theta / (1 << (num_ctrl - ctrl))) | self([ctrl, num_ctrl])
        for targ in range(num_ctrl - 1, ctrl, -1):
            R_ctrl(np.pi / (1 << (targ - ctrl))) | self([ctrl, targ])

    R_targ(theta / (1 << (num_ctrl - 1))) | self([0, num_ctrl])
    for targ in range(num_ctrl - 1, 0, -1):
        R_ctrl(np.pi / (1 << (targ - 1))) | self([0, targ])

    for ctrl in range(1, num_ctrl):
        for targ in range(ctrl + 1, num_ctrl):
            R_ctrl(-np.pi / (1 << (targ - ctrl))) | self([ctrl, targ])
        R_targ(-theta / (1 << (num_ctrl - ctrl))) | self([ctrl, num_ctrl])

    if not reset_ctrl:
        return

    for ctrl in reversed(range(1, num_ctrl)):
        for targ in range(num_ctrl - 1, ctrl, -1):
            R_ctrl(np.pi / (1 << (targ - ctrl))) | self([ctrl, targ])

    for targ in range(num_ctrl - 1, 0, -1):
        R_ctrl(-np.pi / (1 << (targ - 1))) | self([0, targ])

    for ctrl in range(1, num_ctrl):
        for targ in range(ctrl + 1, num_ctrl):
            R_ctrl(-np.pi / (1 << (targ - ctrl))) | self([ctrl, targ])