Initialization data exchange between participants

I understand that there is a “global data” functionality, which enables non-mesh data communication between participants.

However, I’m wondering if it’s possible to exchange initialization data before creating the coupling meshes, since their construction depends on this initial data. While I could manually write this data into the respective input files, that approach would be tedious and should only be a last resort.

@Ya_Squall this is something in our radar since longer, but currently still open:

We have had a first approach to implement this, but the codebase has diverged since, but we wanted to revisit it at some point.

What would your use case be?

Mesh-free data exchange during the preCICE initialization stage (i.e., not during the call to advance) is extremely valuable, offering users significant flexibility in designing the coupling interface. In my case, coupling OpenFOAM with HOS, both parties require preliminary information from one another before configuring the coupling mesh. For OpenFOAM, this information includes the number of HOS grid nodes in the x and y directions, as well as the overall HOS domain size. On the HOS side, the necessary data comprises the boundBox of the embedded OpenFOAM domains.