c------------------------------------------------------------------------------
      subroutine bisect(f, inx0, inx1, tol, maxits,
     +                  status, root, resid, noofit, lastx0, lastx1)
c------------------------------------------------------------------------------
      integer count, limit, maxits, nobracs, noofit, solved, status
      real    f, f0, fmid, inx0, inx1, lastx0, lastx1,
     +        resid, root, tol, x0, x1, xmid
      parameter (solved=0, limit=1, nobrac=2)

      intrinsic abs
      external  f

      x0 = inx0
      x1 = inx1
      f0 = f(x0)
      f1 = f(x1)

      if (f0*f1.gt.0) then
c x0, x1 do not bracket the root
         status = nobrac
      else
c do bisection
         do 10, count = 1, maxits
            xmid = (x0+x1)/2.
            fmid = f(xmid)
            
            if (f0*fmid.lt.0) then
               x1 = xmid
            else 
               x0 = xmid
               f0 = fmid
            end if
            
            if (abs(x1-x0).le.tol) then
               status = solved
               goto 11
            end if
10       continue

         status = limit

11       if (status.eq.solved) then
            root = (x0+x1)/2.
            resid = f(root)
            noofit = count
         end if

         if (status.eq.limit) then
            lastx0 = x0
            lastx1 = x1
         end if

      end if

      end


c------------------------------------------------------------------------------
      real function f(x)
c------------------------------------------------------------------------------
      real x
      intrinsic exp

      f = x - exp(1/x)

      return
      end