AddingInteraction

All places in the code, where something should be added, are commented. These comments start with TO ADD NEW INTERACTION FORMULATION and contain detailed description; the text below is less detailed. Added code should be analogous to interaction formulations already present. The procedure is the following:

• Add new interaction term descriptor in the file const.h. Starting descriptor name with G_ is recommended, as well as adding a descriptive comment.
• Add information about the new interaction formulation in the file param.c.
  • Modify string constants after PAR(int) in the constant array options: add new argument to list {...} and its description to the next string.
  • Add one line to the else-if sequence in the function PARSE_FUNC(int). If new formulation allows sub-arguments, process them here.
  • If the new Green's tensor is non-symmetric (very unlikely) update the definition of reduced_FFT in function VariablesInterconnect accordingly.
  • Add a case to the relevant switch in the function PrintInfo.
• Main part of the code should be added to interaction.c.
  • Add functions that actually perform the calculation of the interaction term, according to the new formulae. At the end you need to have two functions according to the declarations InterTerm_int and InterTerm_real in interaction.h. There are two ways to proceed:
    • either (recommended) create one main function with the following declaration

      static inline void InterTerm_<name>(double qvec[static 3],doublecomplex result[static 6])

      which works for double input vector. After the function definition you specify WRAPPERS_INTER(InterTerm_<name>), which automatically produces wrappers compatible with declarations in interaction.h.
    • or create two separate functions named InterTerm_<name>_int and InterTerm_<name>_real with declarations described in interaction.h. If the new formulation does not support arbitrary real input vector (e.g. it is based on tables), then use NO_REAL_WRAPPER(InterTerm_<name>) instead of the real-input declaration.
  • Update assignment of function pointers in function InitInteraction. If new formulation requires initialization, add it here as well, preferably by a separate function. Also test for possible incompatibilities with other ADDA parameters, if any, and add an exception.
  • If you allocate any memory (for tables, etc.), free it in function FreeInteraction.

Please refer to section Interaction Term of the manual for general overview and precise definition of the interaction term inside ADDA.

If you add a new interaction formulation to ADDA according to the described procedure, please consider contributing your code to be incorporated in future releases. You may also consider generalizing the new formulation for particles near surface, and adding a new reflection formulation.