# @stdlib/math-base-special-cpolar

0.2.2 • Public • Published

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# cpolar

Compute the absolute value and phase of a double-precision complex floating-point number.

## Installation

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

## Usage

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

#### cpolar( z )

Computes the absolute value and phase of a double-precision complex floating-point number.

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

var o = cpolar( new Complex128( 5.0, 3.0 ) );
// returns [ ~5.83, ~0.5404 ]

#### cpolar.assign( z, out, stride, offset )

Computes the absolute value and phase of a double-precision complex floating-point number and assigns results to a provided output array.

var Complex128 = require( '@stdlib/complex-float64-ctor' );
var Float64Array = require( '@stdlib/array-float64' );

var out = new Float64Array( 2 );

var v = cpolar.assign( new Complex128( 5.0, 3.0 ), out, 1, 0 );
// returns <Float64Array>[ ~5.83, ~0.5404 ]

var bool = ( v === out );
// returns true

## Examples

var Complex128 = require( '@stdlib/complex-float64-ctor' );
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var real = require( '@stdlib/complex-float64-real' );
var imag = require( '@stdlib/complex-float64-imag' );
var cpolar = require( '@stdlib/math-base-special-cpolar' );

var re;
var im;
var z;
var o;
var i;

for ( i = 0; i < 100; i++ ) {
re = round( randu()*100.0 ) - 50.0;
im = round( randu()*100.0 ) - 50.0;
z = new Complex128( re, im );
o = cpolar( z );
z = z.toString();
console.log( 'abs(%s) = %d. arg(%s) = %d', z, o[0], z, o[1] );
}

## C APIs

### Usage

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

#### stdlib_base_cpolar( z, cabs, cphase )

Computes the absolute value and phase of 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( 5.0, 3.0 );
double cabs;
double cphase;
stdlib_base_cpolar( z, &cabs, &cphase );

The function accepts the following arguments:

• z: [in] stdlib_complex128_t input value.
• cabs: [out] double* destination for the absolute value.
• cphase: [out] double* destination for the phase value in radians.
double stdlib_base_cpolar( const stdlib_complex128_t z, double *cabs, double *cphase );

### Examples

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

int main( void ) {
const stdlib_complex128_t x[] = {
stdlib_complex128( 3.14, 1.0 ),
stdlib_complex128( -3.14, -1.0 ),
stdlib_complex128( 0.0, 0.0 ),
stdlib_complex128( 0.0/0.0, 0.0/0.0 )
};

double cphase;
double cabs;
double re;
double im;
int i;
for ( i = 0; i < 4; i++ ) {
stdlib_base_cpolar( x[i], &cabs, &cphase );
stdlib_complex128_reim( x[i], &re, &im );
printf( "cpolar(%lf + %lfi) => cabs: %lf, cphase: %lf\n", re, im, cabs, cphase );
}
}

## 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.

## Package Sidebar

### Install

npm i @stdlib/math-base-special-cpolar

### Repository

github.com/stdlib-js/math-base-special-cpolar

stdlib.io

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