stdlib-js
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About stdlib...
</summary>
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copysign
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Return a [double-precision floating-point number][ieee754] with the magnitude of
xand the sign ofy.
bash
npm install @stdlib/math-base-special-copysign
javascript
var copysign = require( '@stdlib/math-base-special-copysign' );
#### copysign( x, y )
Returns a [double-precision floating-point number][ieee754] with the magnitude of x and the sign of y.
javascript
var z = copysign( -3.14, 10.0 );
// returns 3.14
z = copysign( 3.14, -1.0 );
// returns -3.14
z = copysign( 1.0, -0.0 );
// returns -1.0
z = copysign( -3.14, -0.0 );
// returns -3.14
z = copysign( -0.0, 1.0 );
// returns 0.0
NaN has a biased exponent equal to 2047, 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.
javascript
var randu = require( '@stdlib/random-base-randu' );
var copysign = require( '@stdlib/math-base-special-copysign' );
var x;
var y;
var z;
var i;
// Generate random double-precision floating-point numbers `x` and `y` and copy the sign of `y` to `x`...
for ( i = 0; i < 100; i++ ) {
x = (randu()*100.0) - 50.0;
y = (randu()*10.0) - 5.0;
z = copysign( x, y );
console.log( 'x: %d, y: %d => %d', x, y, z );
}
c
#include "stdlib/math/base/special/copysign.h"
#### stdlib_base_copysign( x, y )
Returns a [double-precision floating-point number][ieee754] with the magnitude of x and the sign of y.
c
double v = stdlib_base_copysign( -3.14, 10.0 );
// returns 3.14
double v = stdlib_base_copysign( 3.14, -1.0 );
// returns -3.14
The function accepts the following arguments:
- x: [in] double number from which to derive a magnitude.
- y: [in] double number from which to derive a sign.
c
double stdlib_base_copysign( const double x, const double y );
c
#include "stdlib/math/base/special/copysign.h"
#include <stdio.h>
int main( void ) {
const double x[] = { 3.14, -3.14, 0.0, 0.0/0.0 };
double y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_copysign( x[ i ], -3.0 );
printf( "copysign(%lf, %lf) = %lf\n", x[ i ], -3.0, y );
}
}
@stdlib/math-base/special/flipsign][@stdlib/math/base/special/flipsign]: return a double-precision floating-point number with the magnitude of x and the sign of x\y.
