forum.alglib.net

Your error log tells that autogkintegrate accepts 3 parameters, while you try to pass 7 parameters. If you want to pass some additional data to callback which calculates function, you should pack a_1...a_4 into object and pass this object as third parameter (obj) to autogkintegrate. Unfortunately, this side of integration (passing additional data) is less documented - there is no examples. I hoped that simply writing comments will be enough.