Crate implicit_predicates_core 

Arithmetic building blocks for exact geometric predicates.

This is the no_std, dependency-free core of the implicit-predicates crates. Most users should depend on implicit-predicates instead.

Currently it provides:

• Sign, the result type of every predicate;
• eft, error-free transformations: floating-point sums and products together with their exact rounding errors;
• expansion, exact values represented as sums of f64 components, with exact addition, subtraction, scaling and sign;
• scratch, Scratch, a bump arena over a borrowed buffer that holds the expansions of a computation and runs those operations on them, as well as the exact product of two expansions; Scratch::write lets other code write expansions of its own into it;
• point, Point, the contract every point type implements: an approximation of its coordinates, a bound on their error, and its exact coordinates as expansions in an arena. [f64; 3] implements it as an explicit point;
• filter, the helpers that turn the errors of the points of a call into the uncertainty of the floating-point filter of a predicate.

The optional alloc feature adds an owned arena that grows on the heap, Scratch::growable, so the exact arithmetic can always complete. Without it nothing allocates.

Status: early development. The API is incomplete and may change.

Re-exports

pub use point::ExactCoords;

pub use point::ExactError;

pub use point::Point;

pub use point::Weight;

pub use scratch::Mark;

pub use scratch::Scratch;

pub use scratch::ScratchExhausted;

pub use scratch::Span;

Modules

eft

Error-free transformations: floating-point sums and products together with their exact rounding errors.

expansion

Floating-point expansions: exact values represented as sums of f64 components.

filter

The uncertainty that the errors of the points of a call add to the floating-point filter of a predicate.

point

The contract every point type implements, explicit or implicit.

scratch

A bump arena for expansion arithmetic.

Enums

Sign

The sign of a real quantity.