qat.backend.passes.transform module

class DesugaringPass

Bases: TransformPass

Transforms syntactic sugars and implicit effects. Not that it applies here, but a classical example of a sugar syntax is the ternary expression "cond ? val1 : val2" which is nothing more than an if else in disguise.

The goal of this pass is to desugar any syntactic and semantic sugars. One of these sugars is iteration constructs such as Sweep and Repeat.

run(ir, res_mgr, *args, **kwargs)

Parameters:: ir¶ (InstructionBuilder) – The list of instructions stored in an InstructionBuilder.

class FreqShiftSanitisation(model=None)

Bases: TransformPass

Looks for any active frequency shift pulse channels in the hardware model and adds square pulses for the duration of the shot.

run(ir, res_mgr, *args, **kwargs)

class LowerSyncsToDelays

Bases: TransformPass

Lowers Synchronize instructions to Delay instructions with static times.

Increments through the instruction list, keeping track of the cumulative duration. When Synchronize instructions are encountered, it is replaced with Delay instructions with timings calculated from the cumulative durations.

Warning

Any manipulations of the instruction set that will alter the timeline and occur after this pass could invalidate the intention of the Synchronize instruction.

run(ir, *args, **kwargs)

Return type:: InstructionBuilder

class PydReturnSanitisation

Bases: TransformPass

Squashes all Return instructions into a single one. Adds a Return with all acquisitions if none is found.

run(ir, *args, **kwargs)

Parameters:: ir¶ (QuantumInstructionBuilder) – The list of instructions stored in an QuantumInstructionBuilder.

class RepeatSanitisation(model=None)

Bases: TransformPass

Fixes repeat instructions if any with default values from the HW model. Adds a repeat instructions if none is found.

run(ir, *args, **kwargs)

Parameters:: ir¶ (InstructionBuilder) – The list of instructions stored in an InstructionBuilder.

class ReturnSanitisation

Bases: TransformPass

Squashes all Return instructions into a single one. Adds a Return with all acquisitions if none is found.

run(ir, *args, **kwargs)

Parameters:: ir¶ (InstructionBuilder) – The list of instructions stored in an InstructionBuilder.

class ScopeSanitisation

Bases: TransformPass

Bubbles up all sweeps and repeats to the beginning of the list. Adds delimiter instructions to the repeats and sweeps signifying the end of their scopes.

Intended for legacy existing builders and the relative order of instructions guarantees backwards compatibility.

run(ir, *args, **kwargs)

Parameters:: ir¶ (InstructionBuilder) – The list of instructions stored in an InstructionBuilder.

class SquashDelaysOptimisation

Bases: TransformPass

Looks for consecutive Delay instructions on a pulse channel and squashes them into a single instruction.

Because Synchronize instructions across multiple pulse channels are used so frequently to ensure pulses play at the correct timings, it means we can have sequences of many delays. Reducing the number of delays will simplify timing analysis later in the compilation.

Delay instructions commute with phase related instructions, so the only instructions that separate delays in a meaningful way are: Pulse:, CustomPulse and Acquire instructions. We also need to be careful to not squash delays that contain a variable time.

run(ir, res_mgr, met_mgr, *args, **kwargs)

Parameters:

ir¶ (InstructionBuilder) – The list of instructions stored in an InstructionBuilder.
res_mgr¶ (ResultManager) – The result manager to save the analysis results.
met_mgr¶ (MetricsManager) – The metrics manager to store the number of instructions after optimisation.