Struct PauliFrame 

pub struct PauliFrame {
    pub x_frame: Vec<bool>,
    pub z_frame: Vec<bool>,
}

Classical Pauli frame tracker for fault-tolerant circuits.

Tracks accumulated X and Z corrections that would be needed to map the current (potentially corrupted) state back to the ideal state. Gates commuted through are tracked symbolically rather than applied.

Fields

x_frame: Vec<bool>

X component of the accumulated frame (true = X or Y on that qubit)

z_frame: Vec<bool>

Z component of the accumulated frame (true = Z or Y on that qubit)

Implementations

impl PauliFrame

pub fn new(n_qubits: usize) -> Self

Create a new all-identity Pauli frame for n_qubits qubits.

pub fn n_qubits(&self) -> usize

Number of qubits tracked in this frame.

pub fn apply_pauli_string(&mut self, ps: &PauliString)

Apply a PauliString correction to the frame (XOR into the frame).

I → no change X → flip x_frame Z → flip z_frame Y → flip both x_frame and z_frame

pub fn commute_through_h(&mut self, qubit: usize)

Propagate the Pauli frame through a Hadamard gate on qubit.

H conjugation rule: H X H† = Z, H Z H† = X. Therefore X and Z components are swapped.

pub fn commute_through_s(&mut self, qubit: usize)

Propagate the Pauli frame through an S gate on qubit.

S conjugation rule: S X S† = Y = iXZ, S Z S† = Z. Effect on frame: X → X (x stays), Z component gains x_frame (Z gets +x). If x was true: Z also becomes true (X → Y, so Z component added). If x was false: nothing changes for Z.

pub fn commute_through_cnot(&mut self, ctrl: usize, tgt: usize)

Propagate the Pauli frame through a CNOT gate.

CNOT conjugation rules:

• CNOT (X_c ⊗ I) CNOT† = X_c ⊗ X_t (X propagates forward from ctrl to tgt)
• CNOT (I ⊗ X_t) CNOT† = I ⊗ X_t (X on target unchanged)
• CNOT (Z_c ⊗ I) CNOT† = Z_c ⊗ I (Z on ctrl unchanged)
• CNOT (I ⊗ Z_t) CNOT† = Z_c ⊗ Z_t (Z propagates backward from tgt to ctrl)

pub fn measure_logical_x(&self, logical_x_qubits: &[usize]) -> bool

Measure the logical X operator.

Returns true if the accumulated frame has a logical-Z error (i.e., the Z-frame parity is odd over the logical-X support qubits).

logical_x_qubits: the data qubit indices forming the logical X string.

pub fn measure_logical_z(&self, logical_z_qubits: &[usize]) -> bool

Measure the logical Z operator.

Returns true if the accumulated frame has a logical-X error (i.e., the X-frame parity is odd over the logical-Z support qubits).

logical_z_qubits: the data qubit indices forming the logical Z string.

pub fn merge(&mut self, other: &PauliFrame)

Merge another frame into this one (XOR both x and z components).

pub fn is_identity(&self) -> bool

Returns true if this frame represents the identity (no corrections needed).

Trait Implementations

impl Clone for PauliFrame

fn clone(&self) -> PauliFrame

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PauliFrame

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

Formats the value using the given formatter.

impl Default for PauliFrame

fn default() -> PauliFrame

Returns the “default value” for a type.