ComparatorRzDecomposer

class guppyft.decompose.ComparatorRzDecomposer(*, epsilon: float, max_attempts: int)

Decomposes Rz gates using \(2\lceil(\log_2(1/\epsilon))\rceil\) ancilla qubits via comparators and repeat-until-success. Introduces Toffoli gates. Can be used to decompose angles at runtime. See https://arxiv.org/pdf/2404.05618.

Warning

Using this decomposition together with encoding can produce runtimes that are too long to run on Helios, leading to timeout errors.

In a noiseless setting, the probability of success per attempt is greater than 0.5. The shot will be discarded if all max_attempts fail. Hence, the probability of a shot with \(g\) Rz gates completing is greater than \((1 - 0.5^L)^g\), where \(L\) is max_attempts.

epsilon

Error tolerance in the approximation of the angle.

Type:

float

max_attempts

Maximum number of attempts for repeat-until-success for each Rz gate that is decomposed.

Type:

int

__eq__(other)

Return self==value.

__init__(*, epsilon: float, max_attempts: int) → None

__repr__()

Return repr(self).

n_ancillas() → int

Number of ancilla qubits required for the target precision (\(\epsilon\)).

run(hugr: Hugr[Any], *, inplace: bool = True) → PassResult

Run the pass to transform a HUGR, returning a PassResult.

See implement_pass_run() for a helper function to implement this method.

with_scope(scope: LocalScope | GlobalScope) → ComposablePass

Set the scope configuration for the pass.

As of hugr 0.14.*, this configuration is only guidance, and may be ignored by the pass.

In the future, passes will be required to respect the scope configuration.