flipsignf
Return a single-precision floating-point number with the magnitude of
x
and the sign ofx*y
.
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 to255
, a significand greater than0
, and a sign bit equal to either1
or0
. In which case,NaN
may not correspond to just one but many binary representations. Accordingly, care should be taken to ensure thaty
is notNaN
; 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() {
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 );
}
}