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# npm

## @stdlib/math-base-special-roundb 0.0.6 • Public • Published

# roundb

Round a numeric value to the nearest multiple of b^n on a linear scale.

## Installation

`npm install @stdlib/math-base-special-roundb`

## Usage

`var roundb = require( '@stdlib/math-base-special-roundb' );`

#### roundb( x, n, b )

Rounds a `numeric` value to the nearest multiple of `b^n` on a linear scale.

```// Round a value to 2 decimal places:
var v = roundb( 3.141592653589793, -2, 10 );
// returns 3.14

// If n = 0 or b = 1, `roundb` behaves like `round`:
v = roundb( 3.141592653589793, 0, 2 );
// returns 3.0

// Round a value to the nearest multiple of two:
v = roundb( 5.0, 1, 2 );
// returns 6.0```

## Notes

• Due to rounding error in floating-point numbers, rounding may not be exact. For example,

```var x = 0.2 + 0.1;
// returns 0.30000000000000004

// Should round to 0.3...
var v = roundb( x, -16, 10 );
// returns 0.3000000000000001```

## Examples

```var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var pow = require( '@stdlib/math-base-special-pow' );
var roundb = require( '@stdlib/math-base-special-roundb' );

var x;
var n;
var b;
var v;
var i;

for ( i = 0; i < 100; i++ ) {
x = (randu()*100.0) - 50.0;
n = round( (randu()*10.0) - 5.0 );
b = round( randu()*10.0 );
v = roundb( x, n, b );
console.log( 'x: %d. %d^%d: %d. Rounded: %d.', x, b, n, pow( b, n ), v );
}```

## Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

#### Community ## Keywords

### Install

`npm i @stdlib/math-base-special-roundb`

### Repository

github.com/stdlib-js/math-base-special-roundb

stdlib.io

41

0.0.6