void set_Par()
{
   TXXXParameter *fp = (TXXXParameter*) go4->GetParameter("XXXParameter","TXXXParameter");
   if(!fp) return;

   // set values here-----------
   fp->frP1    = 100;
   fp->frP2    = 200;
   fp->fbHisto = kTRUE;

   fp->fArr.Set(4);
   fp->fArr[0] = 1234;
   fp->fArr[1] = 2345;
   fp->fArr[2] = 3456;
   fp->fArr[3] = 4567;
}