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 half’s 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 for Vector {
    type Tolerance = f32;
    const ZERO_TOL: f32 = 0.0;

    // 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;

    // The is_close function is the only one that must be implemented
    // to implement IsClose. The other functions will delegate to this one.
    fn is_close_tol(
        &self,
        rhs: &Self,
        rel_tol: &f32,
        abs_tol: &f32,
    ) -> bool {
        self.x.is_close_tol(&rhs.x, rel_tol, abs_tol) &&
            self.y.is_close_tol(&rhs.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

Traits

IsClose

Trait used for testing if floating point values are approximately equal