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ForLoopOp

ForLoopOp(indexset, loop_parameter, body, label=None)

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Bases: qiskit.circuit.controlflow.control_flow.ControlFlowOp

A circuit operation which repeatedly executes a subcircuit (body) parameterized by a parameter loop_parameter through the set of integer values provided in indexset.

Parameters

  • indexset (Iterable[int]) – A collection of integers to loop over.
  • loop_parameter (Optional[Parameter]) – The placeholder parameterizing body to which the values from indexset will be assigned.
  • body (QuantumCircuit) – The loop body to be repeatedly executed.
  • label (Optional[str]) – An optional label for identifying the instruction.

Circuit symbol:

     ┌───────────┐
q_0:0
     │           │
q_1:1
     │  for_loop │
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 unit is ‘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

ForLoopOp.add_decomposition(decomposition)

Add a decomposition of the instruction to the SessionEquivalenceLibrary.

assemble

ForLoopOp.assemble()

Assemble a QasmQobjInstruction

broadcast_arguments

ForLoopOp.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

ForLoopOp.c_if(classical, val)

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

ForLoopOp.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

ForLoopOp.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

qiskit.circuit.Instruction

Raises

CircuitError – if the instruction is not composite and an inverse has not been implemented for it.

is_parameterized

ForLoopOp.is_parameterized()

Return True .IFF. instruction is parameterized else False

qasm

ForLoopOp.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

ForLoopOp.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.

replace_blocks

ForLoopOp.replace_blocks(blocks)

Replace blocks and return new instruction. :param blocks: Tuple of QuantumCircuits to replace in instruction.

Returns

New ControlFlowOp with replaced blocks.

reverse_ops

ForLoopOp.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

qiskit.circuit.Instruction

soft_compare

ForLoopOp.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

ForLoopOp.validate_parameter(parameter)

Instruction parameters has no validation or normalization.


Attributes

blocks

condition_bits

Get Clbits in condition.

Return type

List[Clbit]

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.

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