YetAnotherCoupler 3.3.0

This interpolation method allows the user to compute the interpolation weight at runtime and provide them to YAC to be used for the coupling.
The interpolation method first searches for matching source cells for all target points that have to be interpolated. Afterwards a user provided weight computation function (yac_func_compute_weights) is called for all of these target points on the processes which have the required sources cell in their local grid data. The weights returned by this function will later be used for the interpolation.
The weight computation function is provided through the yac_cadd_compute_weights_callback interface. In addition, he can also provide a data pointer, which is later passed to the function.
Callback function key
Key that that was passed to yac_cadd_compute_weights_callback, which allows YAC to identify the weight computation function to be used.