CZGate
CZGate(label=None, ctrl_state=None)
Controlled-Z gate.
This is a Clifford and symmetric gate.
Circuit symbol:
q_0: ─■─
│
q_1: ─■─
Matrix representation:
In the computational basis, this gate flips the phase of the target qubit if the control qubit is in the state.
Create new CZ 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
CZGate.add_decomposition(decomposition)
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
CZGate.assemble()
broadcast_arguments
CZGate.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
CZGate.c_if(classical, val)
Add classical condition on register classical and value val.
control
CZGate.control(num_ctrl_qubits=1, label=None, ctrl_state=None)
Return controlled version of gate. See ControlledGate
for usage.
Parameters
- num_ctrl_qubits (
Optional
[int
]) – number of controls to add to gate (default=1) - label (
Optional
[str
]) – optional gate label - ctrl_state (
Union
[int
,str
,None
]) – The control state in decimal or as a bitstring (e.g. ‘111’). If None, use 2**num_ctrl_qubits-1.
Returns
Controlled version of gate. This default algorithm uses num_ctrl_qubits-1 ancillae qubits so returns a gate of size num_qubits + 2*num_ctrl_qubits - 1.
Return type
Raises
QiskitError – unrecognized mode or invalid ctrl_state
copy
CZGate.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
inverse
CZGate.inverse()
Return inverted CZ gate (itself).
is_parameterized
CZGate.is_parameterized()
Return True .IFF. instruction is parameterized else False
mirror
CZGate.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
power
CZGate.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
Raises
CircuitError – If Gate is not unitary
qasm
CZGate.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
CZGate.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
Raises
CircuitError – If n < 1.
to_matrix
CZGate.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