Crate use_series 

use-series

Small arithmetic and geometric progression helpers for `RustUse`.
Exact checked nth-term and partial-sum helpers for common progression workflows.

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.

Arithmetic progression helpers arithmetic_nth_term and arithmetic_sum cover exact linear progressions with signed steps.

Geometric progression helpers geometric_nth_term and geometric_sum cover exact signed-ratio progressions.

Explicit overflow SeriesError reports the operation that overflowed instead of hiding arithmetic limits.

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);

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);

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. Series utilities for RustUse.

Re-exports

pub use error::SeriesError;

pub use progression::arithmetic_nth_term;

pub use progression::arithmetic_sum;

pub use progression::geometric_nth_term;

pub use progression::geometric_sum;

Modules

error

prelude

Common ergonomic imports for use-series.

progression