@stdlib/math-base-special-croundn NPM

croundn

$NPM version$ $Build Status$ $Coverage Status$

Round each component of a double-precision complex floating-point number to the nearest multiple of 10^n.

Installation

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

Usage

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

croundn( z, n )

Rounds each component of a double-precision complex floating-point number to the nearest multiple of 10^n.

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var v = croundn( new Complex128( -3.141592653589793, 3.141592653589793 ), -2 );
// returns <Complex128>

var re = real( v );
// returns -3.14

var im = imag( v );
// returns 3.14

v = croundn( new Complex128( -3.141592653589793, 3.141592653589793 ), 0 );
// returns <Complex128>

re = real( v );
// returns -3.0

im = imag( v );
// returns 3.0

v = croundn( new Complex128( -12368.0, 12368.0 ), 3 );
// returns <Complex128>

re = real( v );
// returns -12000.0

im = imag( v );
// returns 12000.0

v = croundn( new Complex128( NaN, NaN ), 3 );
// returns <Complex128>

re = real( v );
// returns NaN

im = imag( v );
// returns NaN

Notes

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

var Complex128 = require( '@stdlib/complex-float64' );
var real = require( '@stdlib/complex-real' );
var imag = require( '@stdlib/complex-imag' );

var x = 0.2 + 0.1;
// returns 0.30000000000000004

// Should round components to 0.3:
var v = croundn( new Complex128( x, x ), -16 );
// returns <Complex128>

var re = real( v );
// returns 0.3000000000000001

var im = imag( v );
// returns 0.3000000000000001

Examples

var uniform = require( '@stdlib/random-base-uniform' ).factory;
var Complex128 = require( '@stdlib/complex-float64' );
var floor = require( '@stdlib/math-base-special-floor' );
var croundn = require( '@stdlib/math-base-special-croundn' );

var rand1 = uniform( -5.0, 0.0 );
var rand2 = uniform( -50.0, 50.0 );

var z;
var i;
var n;
for ( i = 0; i < 100; i++ ) {
    z = new Complex128( rand2(), rand2() );
    n = floor( rand1() );
    console.log( 'croundn(%s, %s) = %s', z, n, croundn( z, n ) );
}

C APIs

Usage

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

stdlib_base_croundn( z, n )

Rounds each component of a double-precision complex floating-point number to the nearest multiple of 10^n.

#include "stdlib/complex/float64.h"
#include "stdlib/complex/real.h"
#include "stdlib/complex/imag.h"

stdlib_complex128_t z = stdlib_complex128( -3.141592653589793, 3.141592653589793 );

stdlib_complex128_t out = stdlib_base_croundn( z );

double re = stdlib_real( out );
// returns -3.14

double im = stdlib_imag( out );
// returns 3.14

The function accepts the following arguments:

z: [in] stdlib_complex128_t input value.
n: [in] int32_t integer power of 10.

stdlib_complex128_t stdlib_base_croundn( const stdlib_complex128_t z, const int32_t n );

Examples

#include "stdlib/math/base/special/croundn.h"
#include "stdlib/complex/float64.h"
#include "stdlib/complex/reim.h"
#include <stdio.h>

int main( void ) {
    const stdlib_complex128_t x[] = {
        stdlib_complex128( 3.14, 1.5 ),
        stdlib_complex128( -3.14, -1.5 ),
        stdlib_complex128( 0.0, 0.0 ),
        stdlib_complex128( 0.0/0.0, 0.0/0.0 )
    };

    stdlib_complex128_t v;
    stdlib_complex128_t y;
    double re1;
    double im1;
    double re2;
    double im2;
    int i;
    for ( i = 0; i < 4; i++ ) {
        v = x[ i ];
        y = stdlib_base_croundn( v, -2 );
        stdlib_reim( v, &re1, &im1 );
        stdlib_reim( y, &re2, &im2 );
        printf( "croundn(%lf + %lfi) = %lf + %lfi\n", re1, im1, re2, im2 );
    }
}

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.