generate_preset_occupation_pass_manager

generate_preset_occupation_pass_manager(spec, **kwargs)

Generates a preset transpiler pipeline for the occupation basis, from a LevelSpec.

The truncation and the encoding are given by the spec of this function rather than by the circuit: a bosonic circuit is encoding-agnostic, and choosing them here is what lets the same circuit be lowered at several truncation levels without being rebuilt.

The layout, the state preparation and the operator mapping of the pipeline are all derived from the one spec, so they cannot disagree about which qubits a mode occupies.

Note

A spec built from a single cutoff leaves the number of modes open, so the pipeline serves circuits of any width. A spec with one cutoff per mode fixes it, and the pipeline then only supports circuits with exactly that many modes.

Parameters:

  • spec (LevelSpec) – the LevelSpec with the cutoff of every mode and the encoding that lays the occupation levels out on qubits.

  • kwargs – any additional keyword arguments are forwarded to generate_preset_pass_manager() whose output is used for the qubit stage. Without any, that stage uses Qiskit’s defaults.

Returns:

The preset staged boson-to-qubit transpiler pipeline.

Return type:

MultiStagePassManager