Struct ReferenceSimulator 

pub struct ReferenceSimulator { /* private fields */ }

v2.4.0 — a usable dense-statevector simulator over f64 complex amplitudes, capped at OSS_QUBIT_CAP.

Implementations

impl ReferenceSimulator

pub fn new() -> Self

pub fn reupload_encode( &self, x: &[f64], layers: usize, ) -> Result<StateVector, QuantError>

v2.23.0 — data re-uploading: interleave an angle-encoding of x with a fixed entangling layer, layers times. For layers ≥ 2 the data x re-enters the circuit, so ⟨ψ(x)|ψ(y)⟩ is NO LONGER a quadratic form in x (it becomes a Fourier series in the data — Schuld 2021, arXiv:2008.08605). This is the ONLY provable escape from the amplitude+Pauli quadratic bound (v2.23.0 / the Havlíček route). layers = 1 reduces to a single angle layer (no re-uploading). HONEST: escaping the bound does NOT guarantee advantage on classical text — the v2.23.0 Advantage Witness still gates it.

impl ReferenceSimulator

pub fn polynomial_kernel( a: &StateVector, b: &StateVector, degree: u32, ) -> Result<f64, QuantError>

v2.23.0 — multi-copy polynomial kernel (xᵀy)^d. Loading d copies of the state gives ⟨ψ(x)|ψ(y)⟩^d = (xᵀy)^d for amplitude encoding (Schuld & Killoran). It reaches beyond cosine (degree 1) — but it is still a CLASSICAL polynomial kernel (no quantum advantage), so like every fixed amplitude map it is gated by the v2.23.0 Advantage Witness. degree = 0 is the constant kernel 1; degree = 1 is the linear/cosine kernel xᵀy.

Trait Implementations

impl Clone for ReferenceSimulator

fn clone(&self) -> ReferenceSimulator

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ReferenceSimulator

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ReferenceSimulator

fn default() -> Self

Returns the “default value” for a type.

impl QuantBackend for ReferenceSimulator

fn capacity(&self) -> usize

Maximum register width (qubits) this backend can realise.

fn encode( &self, x: &[f64], scheme: EncodingScheme, ) -> Result<StateVector, QuantError>

Project a classical real vector into a Hilbert-space state (section 3.1).

fn evolve( &self, state: StateVector, circuit: &VariationalCircuit, ) -> Result<StateVector, QuantError>

Evolve a state under a parametric circuit U(θ) (section 3.2).

fn measure( &self, state: &StateVector, observable: &PauliSum, ) -> Result<f64, QuantError>

Expectation E(θ) = ⟨ψ| M |ψ⟩ of a Pauli-sum observable (real, since M is Hermitian).

fn kernel(&self, a: &StateVector, b: &StateVector) -> Result<f64, QuantError>

Quantum-kernel overlap K = |⟨ψ_a|ψ_b⟩|² (section 3.4, fidelity kernel).