function cpolar( z, out, stride, offset ) {
	out[ offset ] = cabs( z );
	out[ offset+stride ] = cphase( z );
	return out;
}
Computes the absolute value and the phase of a double-precision complex floating-point number.

@param {Complex128} z - complex number
@param {Collection} out - output array
@param {integer} stride - output array stride
@param {NonNegativeInteger} offset - output array index offset
@returns {Collection} absolute value and phase (in radians)

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

var o = cpolar( new Complex128( 5.0, 3.0 ), [ 0.0, 0.0 ], 1, 0 );
// returns [ ~5.83, ~0.5404 ]