Crate isclose

This crate provides a set of traits and macros for comparing arbitrary types.

The trait IsClose is implemented by default for f32 and f64.

Additional implementations are also hidden behind the following features:

• half implements IsClose for f16 and bf16
• euclid implements IsClose for [euclid]’s geometric types

Usage:

use isclose::{IsClose, assert_is_close};

// This will fail!
// assert_eq!(0.1 + 0.2, 0.3)

// This will pass
assert!((0.1 + 0.2).is_close(0.3));

// Equivalent, but gives better error messages
assert_is_close!(0.1 + 0.2, 0.3);

You can also implement IsClose for custom types

use isclose::{IsClose, assert_is_close};
use std::borrow::Borrow;

#[derive(Debug)]
struct Vector { x: f32, y: f32 }

impl IsClose<f32> for Vector {
    // Use the same default tolerances as f32
    // You can override the defaults here if necessary
    const ABS_TOL: f32 = <f32 as IsClose>::ABS_TOL;
    const REL_TOL: f32 = <f32 as IsClose>::REL_TOL;

    fn is_close_tol(
        &self,
        other: impl Borrow<Self>,
        rel_tol: impl Borrow<f32>,
        abs_tol: impl Borrow<f32>,
    ) -> bool {
        let (other, rel_tol, abs_tol) = (other.borrow(), rel_tol.borrow(), abs_tol.borrow());
        self.x.is_close_tol(other.x, rel_tol, abs_tol) &&
            self.y.is_close_tol(other.y, rel_tol, abs_tol)
    }
}

assert_is_close!(
    Vector {
        x: 0.1 + 0.2,
        y: 0.2 + 0.4,
    },
    Vector {
        x: 0.3,
        y: 0.6,
    }
)

Macros

assert_is_close

Assert that two values are approximately equal

assert_is_close_abs_tol

Assert that two values are approximately equal using the given absolute tolerance

assert_is_close_rel_tol

Assert that two values are approximately equal using the given relative tolerance

assert_is_close_tol

Assert that two values are approximately equal using the given relative and absolute tolerances

Traits

IsClose

Trait used for testing if floating point values are approximately equal

Zero

Trait used to return a generic zero value for the tolerance