function simplex(x)
      common/pawpar/par(2)
      data p1/0./,p2/0./
      f=par(1)+par(2)*x
      if (abs(par(1)-p1).gt.0.001.or.abs(par(2)-p2).gt.0.001) then
         print *,par(1),par(2)
         p1 = par(1)
         p2 = par(2)
      endif
      simplex=f
      end