InstructionDurations
class qiskit.transpiler.InstructionDurations(instruction_durations=None, dt=None)
Bases: object
Helper class to provide durations of instructions for scheduling.
It stores durations (gate lengths) and dt to be used at the scheduling stage of transpiling. It can be constructed from backend or instruction_durations, which is an argument of transpile(). The duration of an instruction depends on the instruction (given by name), the qubits, and optionally the parameters of the instruction. Note that these fields are used as keys in dictionaries that are used to retrieve the instruction durations. Therefore, users must use the exact same parameter value to retrieve an instruction duration as the value with which it was added.
Methods
from_backend
classmethod from_backend(backend)
Construct an InstructionDurations object from the backend.
Parameters
backend (Backend) – backend from which durations (gate lengths) and dt are extracted.
Returns
The InstructionDurations constructed from backend.
Return type
Raises
TranspilerError – If dt and dtm is different in the backend.
get
get(inst, qubits, unit='dt', parameters=None)
Get the duration of the instruction with the name, qubits, and parameters.
Some instructions may have a parameter dependent duration.
Parameters
- inst (str |qiskit.circuit.Instruction) – An instruction or its name to be queried.
- qubits (int |list[int]) – Qubit indices that the instruction acts on.
- unit (str) – The unit of duration to be returned. It must be ‘s’ or ‘dt’.
- parameters (list[float] | None) – The value of the parameters of the desired instruction.
Returns
The duration of the instruction on the qubits.
Return type
Raises
TranspilerError – No duration is defined for the instruction.
units_used
units_used()
Get the set of all units used in this instruction durations.
Returns
Set of units used in this instruction durations.
Return type
update
update(inst_durations, dt=None)
Update self with inst_durations (inst_durations overwrite self).
Parameters
- inst_durations ('InstructionDurationsType' | None) – Instruction durations to be merged into self (overwriting self).
- dt (float) – Sampling duration in seconds of the target backend.
Returns
The updated InstructionDurations.
Return type
Raises
TranspilerError – If the format of instruction_durations is invalid.