cidentity

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

The identity-function is defined as

for all z.

Installation

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

Usage

var cidentity = require( '@stdlib/math-base-special-cidentity' );

cidentity( z )

Evaluates the identity function for a double-precision complex floating-point number.

var Complex128 = require( '@stdlib/complex-float64-ctor' );
var real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );

var v = cidentity( new Complex128( -1.0, 2.0 ) );
// returns <Complex128>

var re = real( v );
// returns -1.0

var im = imag( v );
// returns 2.0

Examples

var discreteUniform = require( '@stdlib/random-base-discrete-uniform' );
var Complex128 = require( '@stdlib/complex-float64-ctor' );
var cidentity = require( '@stdlib/math-base-special-cidentity' );

var z;
var i;
for ( i = 0; i < 100; i++ ) {
    z = new Complex128( discreteUniform( -50, 50 ), discreteUniform( -50, 50 ) );
    console.log( 'identity(%s) = %s', z, cidentity( z ) );
}

C APIs

Usage

#include "stdlib/math/base/special/cidentity.h"

stdlib_base_cidentity( z )

Evaluates the identity function for a double-precision complex floating-point number.

#include "stdlib/complex/float64/ctor.h"
#include "stdlib/complex/float64/real.h"
#include "stdlib/complex/float64/imag.h"

stdlib_complex128_t z = stdlib_complex128( 2.5, -1.5 );
stdlib_complex128_t out = stdlib_base_cidentity( z );

double re = stdlib_complex128_real( out );
// returns 2.5

double im = stdlib_complex128_imag( out );
// returns -1.5

The function accepts the following arguments:

• z: [in] stdlib_complex128_t input value.

stdlib_complex128_t stdlib_base_cidentity( const stdlib_complex128_t z );

Examples

#include "stdlib/math/base/special/cidentity.h"
#include "stdlib/complex/float64/ctor.h"
#include "stdlib/complex/float64/reim.h"
#include <stdio.h>

int main() {
    const stdlib_complex128_t x[] = {
        stdlib_complex128( 3.14, 1.5 ),
        stdlib_complex128( -3.14, -1.5 ),
        stdlib_complex128( 0.0, 0.0 ),
        stdlib_complex128( 0.0/0.0, 0.0/0.0 )
    };

    stdlib_complex128_t v;
    stdlib_complex128_t y;
    double re1;
    double im1;
    double re2;
    double im2;
    int i;
    for ( i = 0; i < 4; i++ ) {
        v = x[ i ];
        y = stdlib_base_cidentity( v );
        stdlib_complex128_reim( v, &re1, &im1 );
        stdlib_complex128_reim( y, &re2, &im2 );
        printf( "cidentity(%lf + %lfi) = %lf + %lfi\n", re1, im1, re2, im2 );
    }
}

See Also

• @stdlib/math-base/special/cidentityf: evaluate the identity function for a single-precision complex floating-point number.
• @stdlib/math-base/special/identity: evaluate the identity function for a double-precision floating-point number.

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

License

See LICENSE.

Copyright

Copyright © 2016-2024. The Stdlib Authors.