RoundBasedFactory Class
A magic state factory that produces T gate instructions using round-based distillation pipelines.
This factory explores combinations of distillation units (such as "15-to-1 RM prep" and "15-to-1 space efficient") to find optimal configurations that minimize time and space while achieving target error rates. It supports both physical-level distillation (when the input T gate is physically encoded) and logical-level distillation (using lattice surgery via surface codes).
In order to account for the success probability of distillation rounds, the factory models the pipeline using a failure probability requirement (defaulting to 1%) that each round must meet. The number of distillation units per round is adjusted to meet this requirement, which in turn affects the overall space requirements.
Space requirements are calculated using a user-provided function that
aggregates per-round space (e.g., sum or max). The sum function models
the case in which qubits are not reused across rounds, while the max
function models the case in which qubits are reused across rounds.
For the enumeration of logical-level distillation units, the factory relies
on a user-provided ISAQuery (defaulting to SurfaceCode.q()) to explore
different surface code configurations and their corresponding lattice
surgery instructions. These need to be provided by the user and cannot
automatically be derived from the provided implementation ISA, as they can
only contain a subset of the required instructions. The user needs to
ensure that the provided query matches the architecture for which this
factory is being used.
Results are cached to disk for efficiency.
References:
Sergei Bravyi, Alexei Kitaev: Universal Quantum Computation with ideal Clifford gates and noisy ancillas, arXiv:quant-ph/0403025
Michael E. Beverland, Prakash Murali, Matthias Troyer, Krysta M. Svore, Torsten Hoefler, Vadym Kliuchnikov, Guang Hao Low, Mathias Soeken, Aarthi Sundaram, Alexander Vaschillo: Assessing requirements to scale to practical quantum advantage, arXiv:2211.07629
Constructor
RoundBasedFactory(code_query: ~qdk.qre._isa_enumeration.ISAQuery = <factory>, physical_qubit_calculation: ~typing.Callable[[~typing.Iterable], int] = <built-in function sum>, cache_dir: ~pathlib.Path = WindowsPath('C:/Users/cloudtest/.cache/re3/round_based'), use_cache: bool = True)Parameters
| Name | Description |
|---|---|
|
code_query
|
Default value: <factory>
|
|
physical_qubit_calculation
|
Default value: <built-in function sum>
|
|
cache_dir
|
Default value: C:\Users\cloudtest\.cache\re3\round_based
|
|
use_cache
|
Default value: True
|
Methods
| provided_isa | |
| required_isa |
provided_isa
provided_isa(impl_isa: ISA, ctx: ISAContext) -> Generator[ISA, None, None]Parameters
| Name | Description |
|---|---|
|
impl_isa
Required
|
|
|
ctx
Required
|
|
required_isa
static required_isa() -> ISARequirementsAttributes
physical_qubit_calculation
Callable[[Iterable], int] Function to calculate total physical qubits from per-round space requirements, e.g., sum or max. Defaults to sum.
Positional-Only Parameters
| Name | Description |
|---|---|
|
iterable
|
|
Parameters
| Name | Description |
|---|---|
|
start
|
Default value: 0
|
code_query
ISAQuery Query to enumerate QEC codes for logical distillation units. Defaults to SurfaceCode.q().
code_query: ISAQuerycache_dir
Path Directory for caching computed factory configurations. Defaults to ~/.cache/re3/round_based.
cache_dir: Path = WindowsPath('C:/Users/cloudtest/.cache/re3/round_based')use_cache
bool Whether to use cached results. Defaults to True.
use_cache: bool = True