is-close

Check if either:

1. two numbers are equal within a given tolerance
2. the values in two arrays of numbers are equal within a given tolerance

isClose(a, b, rtol, atol, equalNaN, isCloseScaler) ⇒ boolean|Array<boolean>

Check if a is approximately equal to b.

This check uses similar logic to Python math.isClose. By default values are considered to be close if:

abs(a - b) <= max(rtol * max(abs(a), abs(b)), atol).

Returns: boolean - Returns true if both a and b are considered to be close.

Parameter	Type	Description
a	number	First value to compare
b	number	Second value to compare
rtol	number [optional]	The relative tolerance parameter [default = 1e-09]
atol	number [optional]	The absolute tolerance parameter [default = 0.0]
equalNaN	boolean [optional]	Whether to compare NaNs as equal. If true, when a is NaN and b is NaN they will be considered equal. [default = false]
isCloseScaler	IsCloseScaler [optional]	Method used to scale the absolute difference into a relative difference. [default = IsCloseScalers.maxAbsAOrB]

Overload

Returns: Array<boolean> - Returns an array of booleans corresponding to the result of calling isClose() on the individual values in the arrays a and b.

Parameter	Type	Description
a	Array<number>	First value to compare
b	Array<number>	Second value to compare
rtol	number [optional]	The relative tolerance parameter [default = 1e-09]
atol	number [optional]	The absolute tolerance parameter [default = 0.0]
equalNaN	boolean [optional]	Whether to compare NaNs as equal. [default = false]
isCloseScaler	IsCloseScaler [optional]	Method used to scale the absolute difference into a relative difference. [default = IsCloseScalers.maxAbsAOrB]

IsCloseScalers#maxAbsAOrB(a, b) => number

Returns: number - Relative difference scaling: Max(|a|,|b|)

IsCloseScalers#maxAOrB(a, b) => number

Returns: number - Relative difference scaling: Max(a,b)

IsCloseScalers#minAbsAOrB(a, b) => number

Returns: number - Relative difference scaling: Min(|a|,|b|)

IsCloseScalers#minAOrB(a, b) => number

Returns: number - Relative difference scaling: Min(a,b)

IsCloseScalers#meanAbs(a, b) => number

Returns: number - Relative difference scaling: Mean: (|a|+|b|)/2, using Welford's method

IsCloseScalers#mean(a, b) => number

Returns: number - Relative difference scaling: Mean: (a+b)/2, using Welford's method

IsCloseScalers#absA(a) => number

Returns: number - Relative error scaling: abs(a)

IsCloseScalers#absB(a, b) => number

Returns: number - Relative error scaling: abs(b)

Installation

npm install is-close --save

Example Usage

var isClose = require("is-close");
 
// Examples of checking relative difference between first two parameters
console.log(isClose.isClose(1e-7, 1e-8));
console.log(isClose.isClose(1e10, 1.0000000001e10));
console.log(isClose.isClose([1e-7, 1e10], [1e-8, 1.0000000001e10]));
 
// Examples of relative error relative to first parameter 
// - note how result is not symmetric
console.log(isClose.isClose(1.0, 0.9, 0.1, undefined, undefined, isClose.IsCloseScalers.absA));
console.log(isClose.isClose(0.9, 1.0, 0.1, undefined, undefined, isClose.IsCloseScalers.absA));

Output should be

false
true
[false, true]
true
false

TypeScript

import { isClose, IsCloseScalers } from 'is-close';
 
// Examples of checking relative difference between first two parameters
console.log(isClose(1.0, 1.000000001));
console.log(isClose(1.0, 1.0000000001));
console.log(isClose([1.0, 1.0], [1.000000001, 1.0000000001]));
 
// Examples of relative error relative to first parameter 
// - note how result is not symmetric
console.log(isClose(1.0, 0.9, 0.1, undefined, undefined, IsCloseScalers.absA));
console.log(isClose(0.9, 1.0, 0.1, undefined, undefined, IsCloseScalers.absA));

Output should be

false
true
[false, true]
true
false

License

MIT © Steve Bosman