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C4XGate

C4XGate(label=None, ctrl_state=None) GitHub(opens in a new tab)

The 4-qubit controlled X gate.

This implementation is based on Page 21, Lemma 7.5, of [1].

References

[1] Barenco et al., 1995. https://arxiv.org/pdf/quant-ph/9503016.pdf(opens in a new tab)

Create a new 4-qubit controlled X gate.


Attributes

ctrl_state

int

Return the control state of the gate as a decimal integer.

Return type

int

decompositions

Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition

List

Return definition in terms of other basic gates. If the gate has open controls, as determined from self.ctrl_state, the returned definition is conjugated with X without changing the internal _definition.

Return type

List

label

str

Return gate label

Return type

str

params

return instruction params.


Methods

add_decomposition

C4XGate.add_decomposition(decomposition)

Add a decomposition of the instruction to the SessionEquivalenceLibrary.

assemble

C4XGate.assemble()

Assemble a QasmQobjInstruction

Return type

Instruction

broadcast_arguments

C4XGate.broadcast_arguments(qargs, cargs)

Validation and handling of the arguments and its relationship.

For example, cx([q[0],q[1]], q[2]) means cx(q[0], q[2]); cx(q[1], q[2]). This method yields the arguments in the right grouping. In the given example:

in: [[q[0],q[1]], q[2]],[]
outs: [q[0], q[2]], []
      [q[1], q[2]], []

The general broadcasting rules are:

  • If len(qargs) == 1:

    [q[0], q[1]] -> [q[0]],[q[1]]
  • If len(qargs) == 2:

    [[q[0], q[1]], [r[0], r[1]]] -> [q[0], r[0]], [q[1], r[1]]
    [[q[0]], [r[0], r[1]]]       -> [q[0], r[0]], [q[0], r[1]]
    [[q[0], q[1]], [r[0]]]       -> [q[0], r[0]], [q[1], r[0]]
  • If len(qargs) >= 3:

    [q[0], q[1]], [r[0], r[1]],  ...] -> [q[0], r[0], ...], [q[1], r[1], ...]

Parameters

  • qargs (List) – List of quantum bit arguments.
  • cargs (List) – List of classical bit arguments.

Return type

Tuple[List, List]

Returns

A tuple with single arguments.

Raises

CircuitError – If the input is not valid. For example, the number of arguments does not match the gate expectation.

c_if

C4XGate.c_if(classical, val)

Add classical condition on register classical and value val.

control

C4XGate.control(num_ctrl_qubits=1, label=None, ctrl_state=None)

Controlled version of this gate.

Parameters

  • num_ctrl_qubits (int) – number of control qubits.
  • label (str or None) – An optional label for the gate [Default: None]
  • ctrl_state (int or str or None) – control state expressed as integer, string (e.g. ‘110’), or None. If None, use all 1s.

Returns

controlled version of this gate.

Return type

ControlledGate

copy

C4XGate.copy(name=None)

Copy of the instruction.

Parameters

name (str) – name to be given to the copied circuit, if None then the name stays the same.

Returns

a copy of the current instruction, with the name

updated if it was provided

Return type

qiskit.circuit.Instruction

inverse

C4XGate.inverse()

Invert this gate. The C4X is its own inverse.

is_parameterized

C4XGate.is_parameterized()

Return True .IFF. instruction is parameterized else False

mirror

C4XGate.mirror()

For a composite instruction, reverse the order of sub-gates.

This is done by recursively mirroring all sub-instructions. It does not invert any gate.

Returns

a fresh gate with sub-gates reversed

Return type

qiskit.circuit.Instruction

power

C4XGate.power(exponent)

Creates a unitary gate as gate^exponent.

Parameters

exponent (float) – Gate^exponent

Returns

To which to_matrix is self.to_matrix^exponent.

Return type

qiskit.extensions.UnitaryGate

Raises

CircuitError – If Gate is not unitary

qasm

C4XGate.qasm()

Return a default OpenQASM string for the instruction.

Derived instructions may override this to print in a different format (e.g. measure q[0] -> c[0];).

repeat

C4XGate.repeat(n)

Creates an instruction with gate repeated n amount of times.

Parameters

n (int) – Number of times to repeat the instruction

Returns

Containing the definition.

Return type

qiskit.circuit.Instruction

Raises

CircuitError – If n < 1.

to_matrix

C4XGate.to_matrix()

Return a Numpy.array for the gate unitary matrix.

Raises

CircuitError – If a Gate subclass does not implement this method an exception will be raised when this base class method is called.

Return type

ndarray

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