6. The Flash.h file

Flash.h is a critical header file in FLASH4 which holds many of the key quantities related to the particular simulation. The Flash.h file is written by the setup script and should not be modified by the user. The Flash.h file will be different for various applications. When the setup script is building an application, it parses the Config files, collects definitions of variables, fluxes, grid vars, species, and mass scalars, and writes a symbol (an index into one of the data structures maintained by the Grid unit) for each defined entity to the Flash.h header file. This chapter explains these symbols and some of the other important quantities and indices defined in the Flash.h file.