Do you have a simple example of transport depletion coupling?

Check out this test for the TransitionMatrixUpdater.

Specifically, the caseTEST( TransitionMatrixUpdater, StorageBounds47g ) shows how to initialize the TransitionMatrixUpdater with a desired group structure. The input cross sections on the ReactionResource are then mapped to this group structure. This is called the storage group structure. This does not need to be a very fine group structure.

The other group structure is the user group structure. This can be the group structure of the transport code. See the TEST( TransitionMatrixUpdater, UserBounds47g ) for a demonstration of setting the user bounds via set_user_bounds( group_bounds ). Then later when you call update_mg_flux, the flux must be provided in the user group structure.

After the flux is updated, cross sections can be update with update_user_xs. This should generally be done for all the cross sections the transport code is aware of.

Finally, you are ready to get the transition matrix, tmu.get_transition_matrix( &trx );.

This transition matrix can be passed to any of the solvers.

A slightly higher level approach is shown here in the TEST( Example, DISABLED_5MultiZoneWithTransportCoupling ) case, but using the Material and MultiZoneDepleter may be too much overhead for a large scale problem.