Reciprocal Square Root
Compute the reciprocal of the principal square root of a single-precision floating-point number.
The reciprocal of the principal square root is defined as
Usage
var rsqrtf = require( '@stdlib/math/base/special/rsqrtf' );
rsqrtf( x )
Computes the reciprocal (inverse) square root of a single-precision floating-point number.
var v = rsqrtf( 1.0 );
// returns 1.0
v = rsqrtf( 4.0 );
// returns 0.5
v = rsqrtf( 0.0 );
// returns Infinity
v = rsqrtf( NaN );
// returns NaN
v = rsqrtf( Infinity );
// returns 0.0
For negative numbers, the reciprocal square root is not defined.
var v = rsqrtf( -4.0 );
// returns NaN
Examples
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var rsqrtf = require( '@stdlib/math/base/special/rsqrtf' );
var x;
var i;
for ( i = 0; i < 100; i++ ) {
x = round( randu() * 100.0 );
console.log( 'rsqrt(%d) = %d', x, rsqrtf( x ) );
}
C APIs
Usage
#include "stdlib/math/base/special/rsqrtf.h"
stdlib_base_rsqrtf( x )
Computes the reciprocal (inverse) square root of a single-precision floating-point number.
float y = stdlib_base_rsqrtf( 4.0 );
// returns 0.5
The function accepts the following arguments:
- x:
[in] float
input value.
float stdlib_base_rsqrtf( const float x );
Examples
#include "stdlib/math/base/special/rsqrtf.h"
#include <stdio.h>
int main( void ) {
const float x[] = { 3.14f, 9.0f, 0.0f, 0.0f/0.0f };
float y;
int i;
for ( i = 0; i < 4; i++ ) {
y = stdlib_base_rsqrtf( x[ i ] );
printf( "rsqrt(%f) = %f\n", x[ i ], y );
}
}