5.4.2 Recipe 1: single processor

1. In ECCO_CPPOPTIONS.h set:

         #define ALLOW_DIVIDED_ADJOINT
         #undef  ALLOW_DIVIDED_ADJOINT_MPI
   

2. Generate adjoint code. Using the TAF option '-pure', two codes are generated:
   • mdthe_main_loop:
     Is responsible for the forward trajectory, storing of outermost checkpoint levels to file, computation of cost function, and storing of cost function to file (1st step).
   • adthe_main_loop:
     Is responsible for computing one adjoint leg, dump adjoint state to file and write index info to file (2nd and consecutive steps).

     for adjoint code generation, e.g. add '-pure' to TAF option list

         make adtaf
     

   • One modification needs to be made to adjoint codes in S/R adecco_the_main_loop:

     There's a remaining issue with the '-pure' option. The 'call ad...' between 'call ad...' and the read of the snapshot file should be called only in the firt adjoint leg between and . In the ecco-branch, the following lines should be bracketed by an if (idivbeg .GE. nchklev_3) then, thus:

     ...
           xx_psbar_mean_dummy = onetape_xx_psbar_mean_dummy_3h(1)
           xx_tbar_mean_dummy = onetape_xx_tbar_mean_dummy_4h(1)
           xx_sbar_mean_dummy = onetape_xx_sbar_mean_dummy_5h(1)
           call barrier( mythid )
     cAdd(
           if (idivbeg .GE. nchklev_3) then
     cAdd)
     
           call adcost_final( mythid )
           call barrier( mythid )
           call adcost_sst( mythid )
           call adcost_ssh( mythid )
           call adcost_hyd( mythid )
           call adcost_averagesfields( mytime,myiter,mythid )
           call barrier( mythid )
     cAdd(
           endif
     cAdd)
     
     C----------------------------------------------
     C read snapshot
     C----------------------------------------------
           if (idivbeg .lt. nchklev_3) then
             open(unit=77,file='snapshot',status='old',form='unformatted',
          $iostat=iers)
     ...
     

     For the main code, in all likelihood the block which needs to be bracketed consists of adcost_final only.

   • Now the code can be copied as usual to adjoint_model.F and then be compiled:

         make adchange
         then compile
     

Copyright © 2006 Massachusetts Institute of Technology

Last update 2011-01-09