Put the data structures kpp_3d_fields and kpp_const_fields into the data_fields module, rather than passing as arguments. This is what is done for the CAM version of the code, so simplifies the subroutine interfaces, removing ifdefs.
Other minor changes to tidy up the code:
constrain what is loaded through modules by using ONLY
Put the data structures
kpp_3d_fieldsandkpp_const_fieldsinto thedata_fieldsmodule, rather than passing as arguments. This is what is done for the CAM version of the code, so simplifies the subroutine interfaces, removing ifdefs.Other minor changes to tidy up the code:
ONLYRETURNstatements at end of subroutines()to subroutine calls with no argumentsnuoutandnuerrto write to stdout and stderr