The file "tools/sources/functions.h" contains two arrays: One array with the function names (ACT_FUNC_NAMES) and one for the macros which represent the function (ACT_FUNCTIONS). These macros are realized as character strings so they can be written to the generated C-source.
The easiest way to include an own activation function is to write the two necessary entries in the first position of the arrays. After that the constant ``ActRbfNumber'' should be increased. If a new Radial Basis function should be included, the entries should be appended at the end without increasing ActRbfNumber. An empty string ("") should still be the last entry of the array Act_FUNC_NAMES because this is the flag for the end of the array.