function cpolar( z ) {
	return assign( z, [ 0.0, 0.0 ], 1, 0 );
}
Computes the absolute value and the phase of a double-precision complex floating-point number.

@param {Complex128} z - complex number
@returns {Array<number>} absolute value and phase (in radians)

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

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