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@stdlib/math-base-special-floorb 0.0.5 • Public • Published

floorb

Round a numeric value to the nearest multiple of b^n toward negative infinity.

Installation

npm install @stdlib/math-base-special-floorb

Usage

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

floorb( x, n, b )

Rounds a numeric value to the nearest multiple of b^n toward negative infinity.

// Round a value to 4 decimal places:
var v = floorb( 3.141592653589793, -4, 10 );
// returns 3.1415

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

// Round a value to the nearest multiple of two toward negative infinity:
v = floorb( 5.0, 1, 2 );
// returns 4.0

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 = floorb( 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 floorb = require( '@stdlib/math-base-special-floorb' );

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 = floorb( 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.

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