gs2.fpp vs gs2_main.fpp

[Peter Hill]

gs2.fpp looks like the following:

program gs2  
  ! make_lib is a compiler flag used if running with 
  ! an old version of trinity (coupled flux tube code)
  ! MAKE_LIB is now deprecated.
# ifndef MAKE_LIB

   ! code

# else

  implicit none
  call run_gs2

# endif

end program gs2

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where ! code is pretty similar to the body of run_gs2 but with some differences.

Currently, nothing sets MAKE_LIB so we end up with the version in gs2.fpp – should we in fact just be using run_gs2 ?

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[David Dickinson]

The comments say MAKE_LIB is deprecated and just for old versions of trinity so I think we probably can drop it. If we define MAKE_LIB then gs2_main.fpp ends up being a bunch of routines outside of a module (so I guess the old trinity just calls these directly without using them). It might be interesting to see if we can even compile with MAKE_LIB defined.

[Peter Hill]

Nope, a lot of errors. If we remove MAKE_LIB from gs2_main.fpp so that it always uses a module then it does compile. The tests pass, although I’m not sure how many actually run the gs2 program.

I guess you might not want a module if you were calling the functions from C, but there are better ways to make that easier and still use a module.

[David Dickinson]

Did you try make gs2 or make libgs2.a? I think when MAKE_LIB is defined only the later is supported.

[Peter Hill]

Just make which made bin/gs2 and lib/libgs2.a .

[David Dickinson]

I was just wondering if all the errors came from gs2, or if it came from both or just the lib. Or was it just at the compilation stage?

[Peter Hill]

Ah sorry, they were all compilation errors from gs2_main.fpp, mostly like Error: Derived type ‘gs2_program_state_type’ at (1) is being used before it is defined, and Symbol ‘state’ at (1) has no IMPLICIT type. All solved by just removing the #ifdefs from around the module parts:

--- a/src/gs2_main.fpp
+++ b/src/gs2_main.fpp
@@ -11,8 +11,6 @@ module old_interface_store
     logical :: override_miller_geometry = .false.
 end module old_interface_store

-# ifndef MAKE_LIB
-
 !> This module provides the external interface to gs2. It contains functions
 !! to initialize gs2, functions to run gs2, functions to finalize gs2 and 
 !! functions to override/tweak gs2 parameters. 
@@ -302,7 +300,6 @@ module gs2_main
   type(gs2_program_state_type) :: old_iface_state

 contains
-# endif

   !> Starts the global wall clock timer
   !! used by check time. This is useful
@@ -1947,8 +1944,4 @@ contains

   end subroutine gs2_trin_init

-# ifndef MAKE_LIB
 end module gs2_main
-# endif

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[David Dickinson]

Ah ok, that makes sense. I think that shows that this MAKE_LIB approach isn’t really supported anymore – I think we’d need to cut out a whole bunch of other stuff that has been introduced to gs2_main.fpp to retain the old MAKE_LIB approach.