integer function idamaxf(n,dx,incx)

c

c     finds the index of element having max. absolute value.

c     jack dongarra, linpack, 3/11/78.

c     modified 3/93 to return if incx .le. 0.

c     modified 12/3/93, array(1) declarations changed to array(*)

c

      double precision dx(*),dmax

      integer i,incx,ix,n

c

      idamaxf = 0

      if( n.lt.1 .or. incx.le.0 ) return

      idamaxf = 1

      if(n.eq.1)return

      if(incx.eq.1)go to 20

c

c        code for increment not equal to 1

c

      ix = 1

      dmax = dabs(dx(1))

      ix = ix + incx

      do 10 i = 2,n

         if(dabs(dx(ix)).le.dmax) go to 5

         idamaxf = i

         dmax = dabs(dx(ix))

    5    ix = ix + incx

   10 continue

      return

c

c        code for increment equal to 1

c

   20 dmax = dabs(dx(1))

      do 30 i = 2,n

         if(dabs(dx(i)).le.dmax) go to 30

         idamaxf = i

         dmax = dabs(dx(i))

   30 continue

      return

      end