ForLoopOp#

class qiskit.circuit.ForLoopOp(indexset, loop_parameter, body, label=None)[source]#

Bases: 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 (Parameter | None) -- The placeholder parameterizing body to which the values from indexset will be assigned.
body (QuantumCircuit) -- The loop body to be repeatedly executed.
label (str | None) -- 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.

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.

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(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(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()#

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()#: 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];).

Deprecated since 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.

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(blocks)[source]#

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

Returns:: New ControlFlowOp with replaced blocks.

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