Module accum 

The mergeable-accumulator core. merge is the whole game: one op gives one-pass streaming, parallel chunking, and incremental recompute — never downdating.

Re-exports

pub use histogram::HistResult;

pub use histogram::Histogram;

pub use tdigest::TDigest;

pub use tdigest::TDigestResult;

pub use tdigest::quantile_edges;

Modules

histogram

Fixed-bin histogram + fixed-grid ECDF. Plain mergeable accumulators with no RNG dependency, so they live in the always-compiled base.

moments

Moment accumulators. Welford (update), Chan (Variance merge), Terriberry (Moments M3/M4 merge), parallel co-moment (CoMoment merge).

simple

Trivially-mergeable accumulators: Count, Sum (Neumaier), MinMax.

tdigest

Dunning merging t-digest: associative, mergeable streaming quantile/CDF estimation (arXiv:1902.04023). The sole approximation in CommonStats — rank error ≤ 0.75% at the default δ = 100. Exact min/max are tracked separately so the endpoints and extreme tails are exact, not sketch-based.

Traits

Accumulator

Fold observations in, read a result out. empty is the monoid identity.

Mergeable

Combine two partial states. The merge semigroup the resampling seam requires.

Functions

from_slice

Fold an f64 slice into any accumulator, skipping NaN (the Omit policy applied by construction; see crate::nan). Batch entry points build on this.