qiskit.circuit.SwitchCaseOp(target, cases, *, label=None)
A circuit operation that executes one particular circuit block based on matching a given
target against an ordered list of
values. The special value
CASE_DEFAULT can be used to represent a default condition.
This is the low-level interface for creating a switch-case statement; in general, the circuit method
QuantumCircuit.switch() should be used as a context manager to access the builder interface. At the low level, you must ensure that all the circuit blocks contain equal numbers of qubits and clbits, and that the order the virtual bits of the containing circuit should be bound is the same for all blocks. This will likely mean that each circuit block is wider than its natural width, as each block must span the union of all the spaces covered by any of the blocks.
- target (Clbit |ClassicalRegister |expr.Expr) – the runtime value to switch on.
- cases (Iterable[Tuple[Any, QuantumCircuit]]) – an ordered iterable of the corresponding value of the
targetand the circuit block that should be executed if this is matched. There is no fall-through between blocks, and the order matters.
Create a new instruction.
- name (str (opens in a new tab)) – instruction name
- num_qubits (int (opens in a new tab)) – instruction’s qubit width
- num_clbits (int (opens in a new tab)) – instruction’s clbit width
- params (list (opens in a new tab)[int (opens in a new tab)|float (opens in a new tab)|complex (opens in a new tab)|str (opens in a new tab)|ndarray|list (opens in a new tab)|ParameterExpression]) – list of parameters
- duration (int (opens in a new tab) orfloat (opens in a new tab)) – instruction’s duration. it must be integer if
- unit (str (opens in a new tab)) – time unit of duration
- label (str (opens in a new tab) or None) – An optional label for identifying the instruction.
- CircuitError – when the register is not in the correct format.
- TypeError (opens in a new tab) – when the optional label is provided, but it is not a string.
Get the base class of this instruction. This is guaranteed to be in the inheritance tree of
The “base class” of an instruction is the lowest class in its inheritance tree that the object should be considered entirely compatible with for _all_ circuit applications. This typically means that the subclass is defined purely to offer some sort of programmer convenience over the base class, and the base class is the “true” class for a behavioural perspective. In particular, you should not override
base_class if you are defining a custom version of an instruction that will be implemented differently by hardware, such as an alternative measurement strategy, or a version of a parametrised gate with a particular set of parameters for the purposes of distinguishing it in a
Target from the full parametrised gate.
This is often exactly equivalent to
type(obj), except in the case of singleton instances of standard-library instructions. These singleton instances are special subclasses of their base class, and this property will return that base. For example:
>>> isinstance(XGate(), XGate) True >>> type(XGate()) is XGate False >>> XGate().base_class is XGate True
In general, you should not rely on the precise class of an instruction; within a given circuit, it is expected that
Instruction.name should be a more suitable discriminator in most situations.
The classical condition on the instruction.
Get Clbits in condition.
Get the decompositions of the instruction from the SessionEquivalenceLibrary.
Return definition in terms of other basic gates.
Get the duration.
Return instruction label
Is this instance is a mutable unique instance or not.
If this attribute is
False the gate instance is a shared singleton and is not mutable.
Return the name.
Return the number of clbits.
Return the number of qubits.
return instruction params.
Get the time unit of duration.
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
Assemble a QasmQobjInstruction
Validation of the arguments.
- qargs (List) – List of quantum bit arguments.
- cargs (List) – List of classical bit arguments.
Tuple(List, List) – A tuple with single arguments.
CircuitError – If the input is not valid. For example, the number of arguments does not match the gate expectation.
Set a classical equality condition on this instruction between the register or cbit
classical and value
This is a setter method, not an additive one. Calling this multiple times will silently override any previously set condition; it does not stack.
Return a lookup table from case labels to the circuit that would be executed in that case. This object is not generally suitable for creating a new
SwitchCaseOp because any keys that point to the same object will not be grouped.
Return an iterable where each element is a 2-tuple whose first element is a tuple of jump values, and whose second is the single circuit block that is associated with those values.
This is an abstract specification of the jump table suitable for creating new
Create a lookup table that you can use for your own purposes to jump from values to the circuit that would be executed.
Copy of the instruction.
name (str (opens in a new tab)) – name to be given to the copied circuit, if
None then the name stays the same.
a copy of the current instruction, with the name updated if it was provided
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.)
a fresh instruction for the inverse
CircuitError – if the instruction is not composite and an inverse has not been implemented for it.
Return True .IFF. instruction is parameterized else False
Return a default OpenQASM string for the instruction.
Derived instructions may override this to print in a different format (e.g.
measure q -> c;).
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.
Creates an instruction with gate repeated n amount of times.
n (int (opens in a new tab)) – Number of times to repeat the instruction
Containing the definition.
CircuitError – If n < 1.
Replace blocks and return new instruction. :param blocks: Tuple of QuantumCircuits to replace in instruction.
New ControlFlowOp with replaced blocks.
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.
a new instruction with
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.
other (instruction) – other instruction.
are self and other equal up to parameter expressions.
Return a mutable copy of this gate.
This method will return a new mutable copy of this gate instance. If a singleton instance is being used this will be a new unique instance that can be mutated. If the instance is already mutable it will be a deepcopy of that instance.
Instruction parameters has no validation or normalization.