IfElseOp
IfElseOp(condition, true_body, false_body=None, label=None)
Bases: qiskit.circuit.controlflow.control_flow.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.
Parameters
- condition (
Tuple[Union[ClassicalRegister,Clbit],int]) – A condition to be evaluated at circuit runtime which, if true, will trigger the evaluation oftrue_body. Can be specified as either a tuple of aClassicalRegisterto be tested for equality with a givenint, or as a tuple of aClbitto be compared to either aboolor anint. - true_body (
QuantumCircuit) – A program to be executed ifconditionevaluates to true. - false_body (
Optional[QuantumCircuit]) – A optional program to be executed ifconditionevaluates to false. - label (
Optional[str]) – 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.
Parameters
- 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
unitis ‘dt’ - unit (str) – time unit of duration
- label (str or None) – An optional label for identifying the instruction.
Raises
- CircuitError – when the register is not in the correct format.
- TypeError – when the optional label is provided, but it is not a string.
Methods
add_decomposition
IfElseOp.add_decomposition(decomposition)
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
IfElseOp.assemble()
Assemble a QasmQobjInstruction
broadcast_arguments
IfElseOp.broadcast_arguments(qargs, cargs)
Validation of the arguments.
Parameters
- qargs (List) – List of quantum bit arguments.
- cargs (List) – List of classical bit arguments.
Yields
Tuple(List, List) – 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
IfElseOp.c_if(classical, val)
Set a classical equality condition on this instruction between the register or cbit classical and value val.
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
IfElseOp.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
IfElseOp.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.)
Returns
a fresh instruction for the inverse
Return type
Raises
CircuitError – if the instruction is not composite and an inverse has not been implemented for it.
is_parameterized
IfElseOp.is_parameterized()
Return True .IFF. instruction is parameterized else False
qasm
IfElseOp.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
IfElseOp.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.
replace_blocks
IfElseOp.replace_blocks(blocks)
Replace blocks and return new instruction.
Parameters
blocks (Iterable[QuantumCircuit]) – Iterable of circuits for “if” and “else” condition. If there is no “else” circuit it may be set to None or ommited.
Return type
Returns
New IfElseOp with replaced blocks.
reverse_ops
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.
Returns
a new instruction with
sub-instructions reversed.
Return type
soft_compare
IfElseOp.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.
Parameters
other (instruction) – other instruction.
Returns
are self and other equal up to parameter expressions.
Return type
bool
validate_parameter
IfElseOp.validate_parameter(parameter)
Instruction parameters has no validation or normalization.
Attributes
blocks
condition_bits
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
Return type
str
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.