NAME
          iterate - Main time loop for LPJmL

     SYNOPSIS
          #include "lpj.h"

          int iterate(Outputfile *output,
                      Cell grid[],
                      Input input,
                      int npft, int ncft,
                      const Config *config
                     );


     DESCRIPTION
          Function provides main time loop for LPJmL. In each time
          step the global carbon and water fluxes are printed.  The
          arguments of iterate are:

          output
               Pointer to initialized output data. output must be
               initialized by fopenoutput().

          grid Cell grid array allocated and initialized by newgrid().

          input
               Input data initialized by initinput().

          npft Number of natural plant functional types.

          ncft Number of crop plant functional types.

          config
               LPJmL configuration data. Must be read by readconfig().

     RETURN VALUE
          Upon successful completion the last simulation year +1 is
          returned.


     AUTHORS
          For authors and contributors see AUTHORS file


     COPYRIGHT
          (C) Potsdam Institute for Climate Impact Research (PIK), see
          COPYRIGHT file


     SEE ALSO
          readconfig(3), fopenoutput(3), newgrid(3), initinput(3),
          iterateyear(3), fwriterestart(3), flux_sum(3), fprintflux(3)