Advanced users can have additional control over a simulation without having to modify the source code and recompile the code. To do that, the user can provide a set of routines that are called in different stages of the simulation via the Problem file (ProblemFile.f90). A description of the routines of the Problem File can be found in the following section.
UserDefinedStartup: Called before any other routines
UserDefinedFinalSetup: Called after the mesh is read in to allow mesh related initializations or memory allocations.
UserDefinedInitialCondition: called to set the initial condition for the flow. By default it sets an uniform initial condition, but the user can change it.
UserDefinedState1, UserDefinedNeumann: Used to define an user-defined boundary condition.
UserDefinedPeriodicOperation: Called before every time-step to allow periodic operations to be performed.
UserDefinedSourceTermNS: Called to apply source terms to the equation.
UserDefinedFinalize: Called after the solution computed to allow, for example error tests to be performed.
UserDefinedTermination: Called at the the end of the main driver after everything else is done.
The Problem File file must be compiled using a specific Makefile that links it with the libraries of the code. If you are using the horses/dev environment module, you can get templates of the Problemfile.f90 and Makefile with the following commands:
$ horses-get-makefile
$ horses-get-problemfile
Otherwise, search the test cases for examples.\
To run a simulation using user-defined operations, create a folder called SETUP on the path were the simulation is going to be run. Then, store the modified ProblemFile.f90 and the Makefile in SETUP, and compile using:
$ make <<Options>>
where again the options are (bold are default):