# ceiln

Round a complex number to the nearest multiple of `10^n` toward positive infinity.

## Usage

``````var cceiln = require( '@stdlib/math/base/special/cceiln' );
``````

#### cceiln( [out,] re, im, n )

Rounds a `complex` number comprised of a real component `re` and an imaginary component `im` to the nearest multiple of `10^n` toward positive infinity.

``````// Round components to 2 decimal places:
var v = cceiln( -3.141592653589793, 3.141592653589793, -2 );
// returns [ -3.14, 3.15 ]

// If n = 0, `cceiln` behaves like `cceil`:
v = cceiln( -3.141592653589793, 3.141592653589793, 0 );
// returns [ -3.0, 4.0 ]

// Round components to the nearest thousand:
v = cceiln( -12368.0, 12368.0, 3 );
// returns [ -12000.0, 13000.0 ]

v = cceiln( NaN, NaN, 0 );
// returns [ NaN, NaN ]
``````

By default, the function returns real and imaginary components as a two-element `array`. To avoid unnecessary memory allocation, the function supports providing an output (destination) object.

``````var Float32Array = require( '@stdlib/array/float32' );

var out = new Float32Array( 2 );

var v = cceiln( out, -4.2, 5.5, 0 );
// returns <Float32Array>[ -4.0, 6.0 ]

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

## Notes

• When operating on floating-point numbers in bases other than `2`, rounding to specified digits can be inexact. For example,

``````var x = 0.2 + 0.1;
// returns 0.30000000000000004

// Should round components to 0.3:
var v = cceiln( x, x, -16 );
// returns [ 0.3000000000000001, 0.3000000000000001 ]
``````

## Examples

``````var Complex128 = require( '@stdlib/complex/float64' );
var randu = require( '@stdlib/random/base/randu' );
var ceil = require( '@stdlib/math/base/special/ceil' );
var real = require( '@stdlib/complex/real' );
var imag = require( '@stdlib/complex/imag' );
var cceiln = require( '@stdlib/math/base/special/cceiln' );

var re;
var im;
var z;
var o;
var w;
var n;
var i;

for ( i = 0; i < 100; i++ ) {
re = ( randu()*100.0 ) - 50.0;
im = ( randu()*100.0 ) - 50.0;
z = new Complex128( re, im );

n = ceil( randu()*5.0 );
o = cceiln( real(z), imag(z), -n );
w = new Complex128( o[ 0 ], o[ 1 ] );

console.log( 'ceiln(%s,%s) = %s', z.toString(), n.toString(), w.toString() );
}
``````