Coupled simulation of two Code_Saturne instances

[lb_yuan]

Hi Yvan,

I went trough the source code and tried to understand how the coupling works within Code_Saturne, but it seems not that straightforward to understand. Through the documentation, I know that the coupling relies on the PLE library. Is this library used only for the external coupling (coupling with Syrthes, Code_Aster and Code_saturne itself)?
And how the PLE library works, in the way of A or B as shown in the following picture? If it works in the way of A, how the data is exchanged between CPU cores employed by different code, using MPI?

Kind regards,

Bo