Struct FittedCount 

pub struct FittedCount {
    pub base: usize,
    pub diffs: Vec<i128>,
}

An integer-valued polynomial in the scale, in the finite-difference (binomial) basis: value(m) = Σ_k diffs[k] · C(m − base, k). Fitted from consecutive window evaluations; the interpolation certificate is that the difference table vanishes beyond the allowed degree — every window point past the fitting prefix is an exact verification.

Fields

base: usize

diffs: Vec<i128>

Implementations

impl FittedCount

pub fn fit( base: usize, values: &[i128], max_degree: usize, ) -> Option<FittedCount>

Fit values observed at consecutive scales base, base+1, …. Returns None (fail-closed) unless the finite-difference table vanishes above max_degree — which, given values.len() > max_degree + 1, is exactly the statement that the fitted polynomial reproduces every extra window point.

pub fn eval(&self, m: usize) -> i128

Evaluate at any scale m ≥ base (exact i128 binomials).

pub fn parity(&self, m: usize) -> bool

The parity at any scale, via Lucas: C(a, k) is odd iff k & a == k (every base-2 digit of k is ≤ the digit of a). No big integers, valid at every m ≥ base.

pub fn parity_period(&self) -> usize

The period of FittedCount::parity in m: C(·, k) mod 2 has period 2^⌈log₂(k+1)⌉, so the parity’s period is the next power of two above the highest odd-coefficient index.

Trait Implementations

impl Clone for FittedCount

fn clone(&self) -> FittedCount

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FittedCount

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

Formats the value using the given formatter.

impl PartialEq for FittedCount

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for FittedCount