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About stdlib...

We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.

The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.

When you use stdlib, you can be absolutely certain that you are using the most thorough, rigorous, well-written, studied, documented, tested, measured, and high-quality code out there.

To join us in bringing numerical computing to the web, get started by checking us out on GitHub, and please consider financially supporting stdlib. We greatly appreciate your continued support!

roundb

NPM version Build Status Coverage Status

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

Usage

import roundb from 'https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-roundb@deno/mod.js';

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

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 );
}

Usage

#include "stdlib/math/base/special/roundb.h"

stdlib_base_roundb( x, n, b )

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 3.14

The function accepts the following arguments:

  • x: [in] double input value.
  • n: [in] int32_t power.
  • b: [in] int32_t base.
double stdlib_base_roundb( const double x, const int32_t n, const int32_t b );

Examples

#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 );
    }
}

See Also

Notice

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.

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.