function absdiff( x, y ) {
	var out;
	var i;

	out = new Float64Array( x.length );
	for ( i = 0; i < x.length; i++ ) {
		out[ i ] = abs( x[ i ] - y[ i ] );
	}
	return out;
}
Computes the element-wise absolute difference.

@private
@param {Float64Array} x - first input array
@param {Float64Array} y - second input array
@returns {Float64Array} results