Struct PauliSum 

pub struct PauliSum<const W: usize> { /* private fields */ }

Weighted sum of Pauli operators, stored SoA, sorted and deduplicated.

Implementations

impl<const W: usize> PauliSum<W>

pub fn empty(num_qubits: usize) -> Self

Empty sum on num_qubits qubits.

Panics

Panics in debug builds if num_qubits > 64 · W. Caller is responsible for ensuring num_qubits <= 64 · W.

pub fn num_qubits(&self) -> usize

Number of qubits this sum is defined over.

pub fn len(&self) -> usize

Number of non-identity terms after deduplication.

pub fn is_empty(&self) -> bool

true iff the sum has no terms.

pub fn x(&self) -> &[[u64; W]]

Read-only view of the X-part column.

pub fn z(&self) -> &[[u64; W]]

Read-only view of the Z-part column.

pub fn coeff(&self) -> &[Complex64]

Read-only view of the coefficient column.

pub fn add(&self, other: &Self) -> Self

Sum of two PauliSums. Linear-time merge; preserves the sorted invariant. Terms whose coefficients sum to exactly 0+0i are dropped.

Examples

Disjoint keys interleave in sort order; equal keys sum, and an exact-zero combined coefficient drops the term.

use paulistrings::{BuildAccumulator, PauliString, Phase};
use num_complex::Complex64;

let mut a = BuildAccumulator::<1>::new(2);
a.add_term(PauliString::<1>::z(0), Phase::ONE, Complex64::new(1.0, 0.0));
a.add_term(PauliString::<1>::x(1), Phase::ONE, Complex64::new(0.5, 0.0));
let a = a.finalize();

let mut b = BuildAccumulator::<1>::new(2);
b.add_term(PauliString::<1>::z(0), Phase::ONE, Complex64::new(-1.0, 0.0));
let b = b.finalize();

// Z₀ cancels exactly; only X₁ survives.
let r = a.add(&b);
assert_eq!(r.len(), 1);
assert_eq!(r.coeff()[0], Complex64::new(0.5, 0.0));

pub fn scale(&mut self, c: Complex64)

Multiply every coefficient by c in place.

pub fn find(&self, x: &[u64; W], z: &[u64; W]) -> Result<usize, usize>

Locate a Pauli key by binary search; returns Ok(idx) if present, Err(idx) for the insertion point otherwise.

pub fn truncate_by_magnitude(&mut self, eps: f64)

Drop terms whose coefficient magnitude is <= eps. Preserves sort.

pub fn assert_invariants(&self)

Debug-only invariant check. No-op in release builds.

Trait Implementations

impl<const W: usize> Clone for PauliSum<W>

fn clone(&self) -> PauliSum<W>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<const W: usize> Debug for PauliSum<W>

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

Formats the value using the given formatter.

impl<const W: usize> Default for PauliSum<W>

fn default() -> PauliSum<W>

Returns the “default value” for a type.