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

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] |

$3

Returns: Array - 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 | First value to compare |
| b | Array | 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

`sh
npm install is-close --save
`

Example Usage

`javascript
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
`

$3

`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