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Round a numeric value to the nearest multiple of b^n on a linear scale.
import roundb from 'https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-roundb@deno/mod.js';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-
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
import randu from 'https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@deno/mod.js';
import round from 'https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-round@deno/mod.js';
import pow from 'https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-pow@deno/mod.js';
import roundb from 'https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-roundb@deno/mod.js';
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 );
}#include "stdlib/math/base/special/roundb.h"Rounds a numeric value to the nearest multiple of b^n on a linear scale.
double out = stdlib_base_roundb( 3.141592653589793, -2, 10 );
// returns 3.14The function accepts the following arguments:
- x:
[in] doubleinput value. - n:
[in] int32_tpower. - b:
[in] int32_tbase.
double stdlib_base_roundb( const double x, const int32_t n, const int32_t b );#include "stdlib/math/base/special/roundb.h"
#include <stdio.h>
#include <stdint.h>
int main( void ) {
const double x[] = { -5.0, -3.89, -2.78, -1.67, -0.56, 0.56, 1.67, 2.78, 3.89, 5.0 };
const int32_t n[] = { -4, -3, -2, -1, 0, 1, 2, 3, 4, 5 };
const int32_t b[] = { 20, 19, 18, 17, 16, 15, 14, 13, 12, 11 };
double v;
int i;
for ( i = 0; i < 10; i++ ) {
v = stdlib_base_roundb( x[ i ], n[ i ], b[ i ] );
printf( "roundb(%lf, %d, %d) = %lf\n", x[ i ], n[ i ], b[ i ], v );
}
}@stdlib/math-base/special/ceilb: round a numeric value to the nearest multiple of b^n toward positive infinity.@stdlib/math-base/special/floorb: round a numeric value to the nearest multiple of b^n toward negative infinity.@stdlib/math-base/special/round: round a numeric value to the nearest integer.@stdlib/math-base/special/roundn: round a double-precision floating-point number to the nearest multiple of 10^n.
This package is part of stdlib, a standard library 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.
See LICENSE.
Copyright © 2016-2025. The Stdlib Authors.
