use-series

Install

[dependencies]
use-series = "0.0.1"

Foundation

use-series provides a deliberately small exact progression surface. The crate currently exposes zero-based arithmetic and geometric nth-term helpers plus checked partial sums over signed i128 values. Overflow remains explicit through SeriesError rather than relying on panics or silently widening into floating-point behavior.

Helper group	Primary items	Best fit
Arithmetic progressions	`arithmetic_nth_term`, `arithmetic_sum`	Linear sequences, step-based schedules, and exact partial sums
Geometric progressions	`geometric_nth_term`, `geometric_sum`	Exponential growth or decay with exact signed ratios

When to use directly

Choose use-series directly when sequence and series helpers are the only surface you need and you want to keep that concern narrower than the full facade crate.

Scenario	Use `use-series` directly?	Why
You only need arithmetic or geometric progression helpers	Yes	The crate stays smaller than the facade and keeps progression arithmetic explicit
You want exact signed partial sums without floating-point rounding	Yes	The current surface is checked and stays in `i128`
You also need combinatorics, geometry, or other math domains	Usually no	`use-math` can unify the concrete surfaces behind features

Scope

The current surface is intentionally small and concrete.
Progression helpers stay function-oriented instead of introducing wrapper types without extra invariants.
Catalan-family sequences and calculus-specific analysis helpers belong in adjacent focused crates.

Examples

Arithmetic progressions

use use_series::{arithmetic_nth_term, arithmetic_sum};

assert_eq!(arithmetic_nth_term(3, 2, 4)?, 11);
assert_eq!(arithmetic_sum(3, 2, 5)?, 35);

# Ok::<(), use_series::SeriesError>(())

Geometric progressions

use use_series::{geometric_nth_term, geometric_sum};

assert_eq!(geometric_nth_term(2, 3, 4)?, 162);
assert_eq!(geometric_sum(2, 3, 4)?, 80);

# Ok::<(), use_series::SeriesError>(())

Status

use-series is a concrete pre-1.0 crate in the RustUse docs surface. The API remains intentionally small while broader sequence and analysis crates continue to grow around it.

use-series 0.0.5