Struct StatePreparation 

pub struct StatePreparation { /* private fields */ }

A state-preparation unitary A on m qubits, supplied as the closure that applies A to a StateVector. The last qubit (m − 1) is the flag.

The dense matrix of A is extracted once (by applying A to each computational basis state) and reused to build A† and the amplitude operator Q.

Implementations

impl StatePreparation

pub fn from_apply<F>(m: usize, apply: F) -> QuantumResult<Self>

where F: FnMut(&mut StateVector) -> QuantumResult<()>,

Build from a closure that applies A in place to an m-qubit state.

The closure is invoked 2^m times (once per basis column) to extract the dense matrix; it must implement a genuine unitary or downstream unitarity checks will fail.

Errors

• QuantumError::InvalidQubitCount if m == 0 or m > 12 (the dense 2^m × 2^m matrix would be impractical beyond that).
• Propagates any error from the supplied apply closure.

pub fn m(&self) -> usize

Number of qubits m (system + flag).

pub fn good_probability(&self) -> f64

The “good” probability a = ⟨0…0| A† Π_1 A |0…0⟩, computed exactly from the dense matrix: it is the total |amplitude|² of A|0…0⟩ over basis states whose flag bit (qubit m − 1) is set.