@stdlib/math-base-special-identity

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Identity Function

Evaluate the identity function of a double-precision floating-point number.

The identity-function is defined as

for all x.

Installation

npm install @stdlib/math-base-special-identity

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 ) );
}

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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 );
    }
}

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Notice

This package is part of stdlib, a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop stdlib, see the main project repository.

Community

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License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.