API Reference

Gate sets, the gate compiler, the pulse compiler, addons and exceptions are the parts of the public surface you use directly; the Low-level API section at the end collects the abstractions and building blocks they are built from.

Gate sets

CROTGateSet	Star-topology gate set with single-qubit rz/r and a native crot.
FixedCROTGateSet	Star-topology gate set with rz/sx singles and a fixed crotxpi2.
CNOTGateSet	Star-topology gate set with single-qubit rz/rx and a native cx.
CRXGateSet	Star-topology gate set with single-qubit rz/rx and a native crx.

Gate level compiling

GateCompiler	Compile Qiskit circuits into a gate set's native representation.
AdaptiveConfig	Configuration for the adaptive decomposition strategy.
TreeSearchConfig	Configuration for the tree-search strategy.
ErrorAwareTreeSearchConfig	Error-aware search that grows one layer at a time, over a tree search.
ErrorAwareAdaptiveConfig	Error-aware search that grows one full topology sweep per level.
QiskitConfig	Configuration for the Qiskit-transpiler compilation strategy.
ErrorEstimate	The three errors of a compiled circuit.
plot_error_aware_history	Plot the error curves an error-aware compile recorded, against the layer count.

Pulse level compiling

PulseCompiler	Compile native circuits to pulses for a specific gate set, using a bound pulse backend.
SimphonyBackend	Lower a gate set's native gates to pulses on a central-spin device model.
XeedQBackend	Lower star-topology circuits to pulse programs, targeting real XeedQ hardware.
to_xeedq_circuit	Write a compiled circuit in the gate names of the XeedQ toolchain.
from_xeedq_circuit	Read a circuit written in the gate names of the XeedQ toolchain.

Addons

Qiskit

CROTGate	Represent a controlled rotation gate about an axis in the XY plane.
CROTXGate	Represent a controlled rotation gate about the X axis.
CROTXPi2Gate	Represent the fixed, parameterless controlled X rotation at \(\theta = \pi/2\).
CROTYGate	Represent a controlled rotation gate about the Y axis.
append_pauli_readout	Return a copy of circuit with trailing readout-target measurements.
remove_pauli_readouts	Split the trailing readout requests off circuit.

Simphony

append_default_mw_pulse	Add a default microwave pulse to a model.
append_default_rf_pulse	Add a default radio-frequency pulse to a model.
append_default_virtual_z	Add a virtual Z rotation to a model.
append_default_xy8_sequence	Add a default XY8 pulse sequence.
append_default_ddrf_sequence	Add a default DDRF pulse sequence.
append_default_dd_sequence	Add a dynamical-decoupling (DD) controlled nuclear gate.

Exceptions

QuasarError	Base class for errors raised by QUASAR.
ConfigError	Raised when a configuration object or value is invalid.
BackendError	Raised when an underlying compute backend (quasarcpp/simphony) fails.
ConvergenceError	Raised when synthesis ran to completion without reaching tolerance_error.
LicenseError	Raised when the compiled backend has no valid licence to run.
ValidationError	Raised when an argument doesn't satisfy a precondition.
PlateauWarning	Warn that an error-aware search returned a circuit depth bought nothing for.
LayoutWarning	Warn that a circuit's pulses realize a relabeled version of the circuit.

Low-level API

Gate-set abstractions

StarTopologyGateSet	Topology axis: a gate set defined on a star topology.
EntanglerGateSet	Construction axis: one single-qubit basis plus one entangler per placement.
GateSet	Represent a native gate set and its native-circuit metadata.
Gate	Represent a concrete native gate instance.
GateType	Describe a native gate family.

Base configs

CompilerConfig	Represent the options shared by every gate-level compilation strategy.
SynthesisConfig	Represent the parameters every quasarcpp synthesis strategy reads.

Pulse building blocks

AbstractPulseBackend	Base class every pulse backend must inherit.
Benchmarkable	Structural capability: a pulse backend that can estimate its own fidelity.
register_pulse_backend	Register backend_type as a pulse backend for gateset_type.
PulseParameters	Every physical number a pulse backend reads, for one device and gate set.
DriveParameters	One resonant drive: its transition frequency and how it is driven.
DriveStrength	How hard and how long one resonant drive is driven.
DeviceParameters	What the instrument itself contributes to a pulse.
NuclearParameters	One nuclear spin, as the electron-conditioned drives see it.