SwitchCaseOp
class SwitchCaseOp(target, cases, *, label=None)
Bases: ControlFlowOp
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_case()
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.
Parameters
- target (Clbit |ClassicalRegister) – the runtime value to switch on.
- cases (Iterable[Tuple[Any, QuantumCircuit]]) – an ordered iterable of the corresponding value of the
target
and 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.
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
SwitchCaseOp.add_decomposition(decomposition)
Add a decomposition of the instruction to the SessionEquivalenceLibrary.
assemble
SwitchCaseOp.assemble()
Assemble a QasmQobjInstruction
broadcast_arguments
SwitchCaseOp.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
SwitchCaseOp.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.
cases
SwitchCaseOp.cases()
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.
SwitchCaseOp.cases_specifier()
An alternate method that produces its output in a suitable format for creating new SwitchCaseOp
instances.
cases_specifier
SwitchCaseOp.cases_specifier()
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 SwitchCaseOp
instances.
SwitchCaseOp.cases()
Create a lookup table that you can use for your own purposes to jump from values to the circuit that would be executed.
Return type
Iterable[Tuple[Tuple, QuantumCircuit]]
copy
SwitchCaseOp.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
SwitchCaseOp.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
SwitchCaseOp.is_parameterized()
Return True .IFF. instruction is parameterized else False
qasm
SwitchCaseOp.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
SwitchCaseOp.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
SwitchCaseOp.replace_blocks(blocks)
Replace blocks and return new instruction. :param blocks: Tuple of QuantumCircuits to replace in instruction.
Returns
New ControlFlowOp with replaced blocks.
Return type
reverse_ops
SwitchCaseOp.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
SwitchCaseOp.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
SwitchCaseOp.validate_parameter(parameter)
Instruction parameters has no validation or normalization.
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
return instruction params.
unit
Get the time unit of duration.