= How to add a new flag =


== Declare the new flag ==

For consistency reasons new flags are to be declared in a structure. First, you need to declare the new flag as a logical in ../modeles/ORCHIDEE/src_parameter/constantes.f90 in the existing control type block. Variables declared in constantes.f90 are global

{{{
TYPE control_type
   LOGICAL :: ok_NameOfNewFlag      !! Explanation of new flag
END TYPE control_type
}}}

Next, you store the flags in a common variable named 'control'. This is done in ../modeles/ORCHIDEE/src_sechiba/sechiba.f90 in the subroutine sechiba_init

{{{
control%ok_NameOfNewFlag = control_in%ok_NameOfNewFlag
}}}

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== Read the flag from the parameter file ==

The flag can be read in the routine where you need it, if the flag is shared among routines you can read it in the first common routine. Quite a few flags that control the flow of th emodel are read in intersurf.f90 in the subroutine intsurf_config. Document the flag using the default keywords (see below). An example is shown for the flag called control%ok_functional_allocation 

{{{
!Config Key  = STOMATE_FUNCTIONAL_ALLOCATION
!Config Desc = use Friedlingstein etal. 1999 or Zaehle et al 2010 for allocation
!Config Def  = n
!Config Help = set to TRUE if functional allocation is to be activated
!
control_flags%ok_functional_allocation = .FALSE.
CALL getin_p('STOMATE_FUNCTIONAL_ALLOCATION',control_flags%ok_functional_allocation)
WRITE(*,*) 'Allocation is based on plant structure: ',control_flags%ok_functional_allocation
}}}