Identity Function
Evaluate the identity function of a double-precision floating-point number.
The identity-function is defined as
for all x
.
Usage
var identity = require( '@stdlib/math/base/special/identity' );
identity( x )
Evaluates the identity function for a double-precision floating-point number.
var v = identity( -1.0 );
// returns -1.0
v = identity( 2.0 );
// returns 2.0
v = identity( 0.0 );
// returns 0.0
v = identity( -0.0 );
// returns -0.0
v = identity( NaN );
// returns NaN
Examples
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var identity = require( '@stdlib/math/base/special/identity' );
var rand;
var i;
for ( i = 0; i < 100; i++ ) {
rand = round( randu() * 100.0 ) - 50.0;
console.log( 'identity(%d) = %d', rand, identity( rand ) );
}
C APIs
Usage
#include "stdlib/math/base/special/identity.h"
stdlib_base_identity( x )
Evaluates the identity function for a double-precision floating-point number.
double y = stdlib_base_identity( 2.0 );
// returns 2.0
The function accepts the following arguments:
- x:
[in] double
input value.
double stdlib_base_identity( const double x );
Examples
#include "stdlib/math/base/special/identity.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_identity( x[ i ] );
printf( "f(%lf) = %lf\n", x[ i ], y );
}
}