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README.md |
Copysign
Return a double-precision floating-point number with the magnitude of
x
and the sign ofy
.
Usage
var copysign = require( '@stdlib/math/base/special/copysign' );
copysign( x, y )
Returns a double-precision floating-point number with the magnitude of x
and the sign of y
.
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
Notes
- According to the IEEE754 standard, a
NaN
has a biased exponent equal to2047
, 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
, else behavior may be indeterminate.
Examples
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 );
}