Struct EnginePauliString 

pub struct EnginePauliString {
    pub nqubits: usize,
    pub x: Vec<u64>,
    pub z: Vec<u64>,
    /* private fields */
}

A Pauli operator on nqubits qubits, with a two-bit phase exponent of i.

Equality is structural — it compares the stored phase byte and both bitsets, not the operator up to phase.

Examples

use ticit::{neg, pauli_string};

let xyz = pauli_string("XYZ")?;
assert_eq!(xyz.to_string(), "XYZ");
assert_eq!(neg(xyz).to_string(), "-XYZ");

Fields

nqubits: usize

Number of qubits in the operator.

x: Vec<u64>

Packed LSB-first X bits; qubit q is bit q & 63 of word q >> 6.

z: Vec<u64>

Packed LSB-first Z bits, with the same layout as x.

Implementations

impl PauliString

pub fn new(nqubits: usize) -> PauliString

Identity on nqubits qubits.

pub fn xbit(&self, q: usize) -> bool

Returns whether qubit q has an X component.

Panics

Panics if q >= self.nqubits.

pub fn zbit(&self, q: usize) -> bool

Returns whether qubit q has a Z component.

Panics

Panics if q >= self.nqubits.

pub fn set_xbit(&mut self, q: usize, value: bool)

Sets or clears the X component on qubit q.

Panics

Panics if q >= self.nqubits.

pub fn set_zbit(&mut self, q: usize, value: bool)

Sets or clears the Z component on qubit q.

Panics

Panics if q >= self.nqubits.

pub fn phase_exponent(&self) -> i32

Exponent of i in the stored phase, in 0..=3.

pub fn set_phase(&mut self, phase_exponent: i32)

Sets the phase exponent modulo 4; negative inputs wrap the same way the C++ & 3 on a signed int does.

pub fn phase_shift(&mut self, delta: i32)

Adds delta to the stored phase exponent modulo four.

pub fn has_nonidentity_body(&self) -> bool

Returns whether any qubit carries X, Y, or Z instead of identity.

pub fn same_body(&self, other: &PauliString) -> bool

Body equality, ignoring phase. Rotation fusion uses this as the identity test for “same Pauli, possibly different sign”.

pub fn single(nqubits: usize, q: usize, pauli: Pauli) -> PauliString

The string with pauli at q and identity everywhere else.

Panics

Panics if q >= nqubits.

pub fn from_terms( nqubits: usize, terms: impl IntoIterator<Item = (usize, Pauli)>, ) -> PauliString

Collects (qubit, pauli) terms into a string on nqubits qubits.

Terms are assignments, not factors: a repeated index keeps the last Pauli given for it rather than multiplying the two.

Panics

Panics if any index is >= nqubits.

pub fn get(&self, q: usize) -> Pauli

The single-qubit Pauli acting on q.

Panics

Panics if q >= nqubits.

pub fn set(&mut self, q: usize, pauli: Pauli)

Replaces the Pauli acting on q.

The stored phase absorbs the body’s implicit i per Y, so a string built only from set is Hermitian — the phase convention documented at the top of this module.

Panics

Panics if q >= nqubits.

pub fn x_words(&self) -> &[u64]

The packed X bits, for callers doing whole-word algebra.

pub fn z_words(&self) -> &[u64]

The packed Z bits, with the same layout as x_words.

pub fn max_support(&self) -> Option<usize>

The largest qubit carrying a non-identity Pauli, or None for identity.

This — not nqubits — bounds the register the string actually acts on, so it is what a caller sizing a register against an observable wants.

pub fn commutes_with(&self, other: &PauliString) -> bool

Whether self and other commute as operators.

Trait Implementations

impl Clone for PauliString

fn clone(&self) -> PauliString

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PauliString

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

Formats the value using the given formatter.

impl Default for PauliString

fn default() -> PauliString

Returns the “default value” for a type.

impl Display for PauliString

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

Formats the value using the given formatter.

impl Eq for PauliString

impl Mul for PauliString

type Output = PauliString

The resulting type after applying the * operator.

fn mul(self, rhs: PauliString) -> PauliString

Performs the * operation.

impl Mul<&PauliString> for &PauliString

fn mul(self, rhs: &PauliString) -> PauliString

Panics if the operands act on different numbers of qubits: every caller multiplies rows of one tableau, so a mismatch is a wiring bug.

type Output = PauliString

The resulting type after applying the * operator.

impl PartialEq for PauliString

fn eq(&self, other: &PauliString) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for PauliString

impl TryFrom<&str> for PauliString

type Error = TicitError

The type returned in the event of a conversion error.

fn try_from(ops: &str) -> Result<PauliString, TicitError>

Performs the conversion.