@stdlib/math-base-special-flipsignf NPM

flipsignf

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

Return a single-precision floating-point number with the magnitude of x and the sign of x*y.

Installation

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

Usage

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

flipsignf( x, y )

Returns a single-precision floating-point number with the magnitude of x and the sign of x*y (i.e., only return -x when y is a negative number).

var z = flipsignf( -3.0, 10.0 );
// returns -3.0

z = flipsignf( -3.0, -1.0 );
// returns 3.0

z = flipsignf( 1.0, -0.0 );
// returns -1.0

z = flipsignf( -3.0, -0.0 );
// returns 3.0

z = flipsignf( -0.0, 1.0 );
// returns -0.0

z = flipsignf( 0.0, -1.0 );
// returns -0.0

Notes

According to the IEEE 754 standard, a NaN has a biased exponent equal to 255, a significand greater than 0, and a sign bit equal to either 1 or 0. In which case, NaN may not correspond to just one but many binary representations. Accordingly, care should be taken to ensure that y is not NaN; otherwise, behavior may be indeterminate.

Examples

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

var x;
var y;
var z;
var i;

// Generate random numbers `x` and `y` and flip the sign of `x` only if `y` is negative...
for ( i = 0; i < 100; i++ ) {
    x = (randu()*100.0) - 50.0;
    y = (randu()*10.0) - 5.0;
    z = flipsignf( x, y );
    console.log( 'x: %d, y: %d => %d', x, y, z );
}

C APIs

Usage

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

stdlib_base_flipsignf( x, y )

Returns a single-precision floating-point number with the magnitude of x and the sign of x*y.

float v = stdlib_base_flipsignf( -3.0f, 10.0f );
// returns -3.0f

float v = stdlib_base_flipsignf( -3.0f, -1.0f );
// returns 3.0f

The function accepts the following arguments:

x: [in] float number from which to derive a magnitude.
y: [in] float number from which to derive a sign.

float stdlib_base_flipsignf( const float x, const float y );

Examples

#include "stdlib/math/base/special/flipsignf.h"
#include <stdio.h>

int main( void ) {
    const float x[] = { 3.0f, -3.0f, 0.0f, 0.0f/0.0f };

    float y;
    int i;
    for ( i = 0; i < 4; i++ ) {
        y = stdlib_base_flipsignf( x[ i ], -3.0f );
        printf( "flipsignf(%f, %f) = %f\n", x[ i ], -3.0f, y );
    }
}

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.