Dump variables to dat files

There are two ways to add variables to the dat files:

Extra variables

This method adds extra variables in the dat file (which is also used for restart).

This method consists in: 1. Assign an index in the variable list w in usr_init subroutine (in mod_usr.t) using var_set_extravar 2. Implement one of the user methods which are called every timestep: usr_process_grid, usr_modify_output,... and set there the extra variables (and properly assign the pointer to the implemented subroutine in usr_init).

.

New dat files

With this method an extra dat file is generated with new variables. (see io/mod_convert.fpp). 1. Set convert_type to "dat_generic_mpi":

&filelist
      ...
      convert_type = "dat_generic_mpi"
      ...
/

1. Add a convert method in usr_init subroutine (use mod_convert):

    call add_convert_method2(dump_vars, 4, "jx jy jz sxr", "_aux_") 

or

    call add_convert_method(dump_vars, 4, (/" jx", " jy", " jz", "sxr"/), "_aux_")

The first way is preferred as because Fortran requires the strings in an array to have the same length and extra spaces might be necessary for this. The last argument _aux_ is the suffix added to base_filename in order to generate the name of the new dat file.

1. Implement dump_vars function:

        function dump_vars(ixI^L, ixO^L, w, x, nwc) result(wnew)
          use mod_global_parameters
          use mod_thermal_emission
          integer, intent(in)             :: ixI^L,ixO^L, nwc
          double precision, intent(in)    :: w(ixO^S, 1:nw)
          double precision, intent(in)    :: x(ixO^S,1:ndim)
          double precision    :: wnew(ixO^S, 1:nwc)
          double precision :: current(ixI^S,7-2*ndir:3)
          integer :: idirmin,idir
          double precision    :: tmp(ixI^S)
          call get_current(w,ixI^L,ixO^L,idirmin,current)
          wnew(ixO^S,1) =  current(ixO^S,1)
          wnew(ixO^S,2) =  current(ixO^S,2)
          wnew(ixO^S,3) =  current(ixO^S,3)
          call get_SXR(ixI^L,ixO^L,w,x,te_fl_c,tmp,9,12)
          wnew(ixO^S,4) =  tmp(ixO^S)
        end function dump_vars

Examples of use in the main code

1. For the mhd model for dumping full variables by setting in the parameter file:

&mhd_list
    mhd_dump_full_vars=.true.
/  

A new file is created with hardcoded suffix new.