function dlapy3( x, y, z ) {
	var hugeval;
	var xabs;
	var yabs;
	var zabs;
	var w;

	hugeval = dlamch( 'O' );
	xabs = abs( x );
	yabs = abs( y );
	zabs = abs( z );

	w = max( xabs, yabs, zabs );

	if ( w === 0.0 || w > hugeval ) {
		return xabs + yabs + zabs;
	}
	return w * sqrt( abs2( xabs / w ) + abs2( yabs / w ) + abs2( zabs / w ) );
}
Computes `sqrt(x^2 + y^2 + z^2)` in a manner which doesn't cause unnecessary overflow.

@param {number} x - first input number
@param {number} y - second input number
@param {number} z - third input number
@returns {number} `sqrt(x^2 + y^2 + z^2)`

@example
var out = dlapy3( 3.0, 4.0, 12.0 );
// returns 13.0