Game Maker Clausen Functions

///clausen(x[, p])

/*
    p should be a value between 1 and 3
    prec is theoretically infinity but 15 or 20 is usually enough
    returning result instead of -result will flip the function (fast rise flow fall)
*/

var xx = argument[0];
if argument_count >= 2 var _p = argument[1];
else var _p = 2;
var prec = 15;

result = 0;
for (n = 1; n <= prec; n++) {
    result += (dsin(n*xx) / power(n, _p));
}
return -result;