******************* This email originates from outside Imperial. Do not click on links and attachments unless you recognise the sender. If you trust the sender, add them to your safe senders list https://spam.ic.ac.uk/SpamConsole/Senders.aspx to disable email stamping for this address. ******************* Dear Nektar++ team, I hope this email finds you well. I am trying to couple Nektar++ (AcousticSolver) with a Python code using CWIPI 1.3.0. I’m running into a handshake failure that looks like an API mismatch between the two sides. Although I confirmed with： ldd $(which AcousticSolver) | grep -i cwp libcwp.so.1.3.0 => /.../lib/libcwp.so.1.3.0 Logs (abridged to the relevant parts) Python side clearly initializes the new API: [PyApp] Rank 0: Calling pycwp.init()... [CWP_Init][rank=0] called with n_code=1, is_active_rank=1 [CWP_Init][rank=0] code_names[0] = 'PyApp_' Nektar++ side appears to initialize the legacy API: [APDB][init] ENTER: comm_rank=1 comm_size=2 applicationName=nektar ... mergeNames raw buffer (len=8): PyApp_\0\0 ... python: .../cwipi/src/new/codePropertiesDB.cxx:270: ... Assertion `index <= totalLength' failed. My understanding is: that Nektar++ links to CWIPI 1.3.0, the logs show that Nektar++ still calls the legacy API (cwipi_init, ApplicationPropertiesDataBase), while the Python side uses the new API (CWP_Init, CodePropertiesDB). This causes inconsistent name exchange (PyApp_[python side application name] vs empty string) and an assertion failure in codePropertiesDB.cxx. From CommCwipi.cpp I see: cwipi_init(MPI_COMM_WORLD, localName.c_str(), &localComm); so it seems Nektar++ is not yet adapted to the new API. My questions: 1. Is it correct that Nektar++ currently does not support the new API? 2. If yes, is there a way to configure or build Nektar++ so that it uses the new API, or would migrating CommCwipi.cpp be necessary? Roughly how much effort would such a migration take? 3. Is there any other way to solve this problem? Since CWIPI no longer provides downloads of the old version code, I wanted to check with you on the recommended way forward. Thank you very much for your guidance. Best regards, Dao