IfElseOp#

class qiskit.circuit.IfElseOp(condition, true_body, false_body=None, label=None)[source]#

Bases : ControlFlowOp

A circuit operation which executes a program (true_body) if a provided condition (condition) evaluates to true, and optionally evaluates another program (false_body) otherwise.

Paramètres:

condition (tuple[ClassicalRegister, int] | tuple[Clbit, int] | expr.Expr) – A condition to be evaluated at circuit runtime which, if true, will trigger the evaluation of true_body. Can be specified as either a tuple of a ClassicalRegister to be tested for equality with a given int, or as a tuple of a Clbit to be compared to either a bool or an int.
true_body (QuantumCircuit) – A program to be executed if condition evaluates to true.
false_body (QuantumCircuit | None) – A optional program to be executed if condition evaluates to false.
label (str | None) – An optional label for identifying the instruction.

If provided, false_body must be of the same num_qubits and num_clbits as true_body.

The classical bits used in condition must be a subset of those attached to the circuit on which this IfElseOp will be appended.

Circuit symbol:

     ┌───────────┐
q_0: ┤0          ├
     │           │
q_1: ┤1          ├
     │  if_else  │
q_2: ┤2          ├
     │           │
c_0: ╡0          ╞
     └───────────┘

Create a new instruction.

Paramètres:

name (str) – instruction name
num_qubits (int) – instruction’s qubit width
num_clbits (int) – instruction’s clbit width
params (list[int|float|complex|str|ndarray|list|ParameterExpression]) – list of parameters
duration (int or float) – instruction’s duration. it must be integer if unit is “dt”
unit (str) – time unit of duration
label (str or None) – An optional label for identifying the instruction.

Lève:

CircuitError – when the register is not in the correct format.
TypeError – when the optional label is provided, but it is not a string.

Attributes

blocks#

condition_bits#: Get Clbits in condition.

decompositions#: Get the decompositions of the instruction from the SessionEquivalenceLibrary.

definition#: Return definition in terms of other basic gates.

duration#: Get the duration.

label#: Return instruction label

name#: Return the name.

num_clbits#: Return the number of clbits.

num_qubits#: Return the number of qubits.

params#

unit#: Get the time unit of duration.

Methods

add_decomposition(decomposition)#: Add a decomposition of the instruction to the SessionEquivalenceLibrary.

assemble()#: Assemble a QasmQobjInstruction

broadcast_arguments(qargs, cargs)#

Validation of the arguments.

Paramètres:

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

Yields:

Tuple(List, List) – A tuple with single arguments.

Lève:

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

c_if(classical, val)[source]#: Set a classical equality condition on this instruction between the register or cbit classical and value val.

Note

This is a setter method, not an additive one. Calling this multiple times will silently override any previously set condition; it does not stack.

copy(name=None)#

Copy of the instruction.

Paramètres:: name (str) – name to be given to the copied circuit, if None then the name stays the same.
Renvoie:: a copy of the current instruction, with the name updated if it was provided
Type renvoyé:: qiskit.circuit.Instruction

inverse()#

Invert this instruction.

If the instruction is composite (i.e. has a definition), then its definition will be recursively inverted.

Special instructions inheriting from Instruction can implement their own inverse (e.g. T and Tdg, Barrier, etc.)

Renvoie:: a fresh instruction for the inverse
Type renvoyé:: qiskit.circuit.Instruction
Lève:: CircuitError – if the instruction is not composite and an inverse has not been implemented for it.

is_parameterized()#: Return True .IFF. instruction is parameterized else False

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];).

Obsolète depuis la version 0.25.0: The method qiskit.circuit.instruction.Instruction.qasm() is deprecated as of qiskit-terra 0.25.0. It will be removed no earlier than 3 months after the release date. Correct exporting to OpenQASM 2 is the responsibility of a larger exporter; it cannot safely be done on an object-by-object basis without context. No replacement will be provided, because the premise is wrong.

repeat(n)#

Creates an instruction with gate repeated n amount of times.

Paramètres:: n (int) – Number of times to repeat the instruction
Renvoie:: Containing the definition.
Type renvoyé:: qiskit.circuit.Instruction
Lève:: CircuitError – If n < 1.

replace_blocks(blocks)[source]#

Replace blocks and return new instruction.

Paramètres:: blocks (Iterable[QuantumCircuit]) – Iterable of circuits for « if » and « else » condition. If there is no « else » circuit it may be set to None or omitted.
Renvoie:: New IfElseOp with replaced blocks.
Type renvoyé:: IfElseOp

reverse_ops()#

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

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

Renvoie:

a new instruction with: sub-instructions reversed.

Type renvoyé:

qiskit.circuit.Instruction

soft_compare(other)#

Soft comparison between gates. Their names, number of qubits, and classical bit numbers must match. The number of parameters must match. Each parameter is compared. If one is a ParameterExpression then it is not taken into account.

Paramètres:: other (instruction) – other instruction.
Renvoie:: are self and other equal up to parameter expressions.
Type renvoyé:: bool

validate_parameter(parameter)#: Instruction parameters has no validation or normalization.