floorn

Round a numeric value to the nearest multiple of 10^n toward negative infinity.

Usage

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

floorn( x, n )

Rounds a numeric value to the nearest multiple of 10^n toward negative infinity.

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

// If n = 0, `floorn` behaves like `floor`:
v = floorn( 3.141592653589793, 0 );
// returns 3.0

// Round a value to the nearest thousand:
v = floorn( 12368.0, 3 );
// returns 12000.0

Notes

When operating on floating-point numbers in bases other than 2, rounding to specified digits can be inexact. For example,

var x = -0.2 - 0.1;
// returns -0.30000000000000004

// Should round to -0.3:
var v = floorn( x, -16 );
// returns -0.3000000000000001

Examples

var randu = require( '@stdlib/random/base/randu' );
var floorn = require( '@stdlib/math/base/special/floorn' );

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

for ( i = 0; i < 100; i++ ) {
    x = (randu()*100.0) - 50.0;
    n = floorn( randu()*5.0, 0 );
    v = floorn( x, -n );
    console.log( 'x: %d. Number of decimals: %d. Rounded: %d.', x, n, v );
}