Rationale

Traviando's trace format supports a partition of the set of state variables into processes such that a process contains a set of state variables. Vice versa, each state variable belongs to a single process (with the exception of global state variables).
An action A accesses (makes value assignments) to a set of state variables SV(A). An action is also declared to be either a local action, i.e., local to some process P, such that SV(A) is a subset of the state variables associated with process P, or an interaction. The two possible kinds of interactions are directed and undirected interactions. For an undirected interaction A, SV(A) distributes over sets of state variables of several processes (at least 2 processes). For a directed interaction A, SV(A) distributes over sets of state variables of exactly two processes and one process is declared as a source, the other as a destination of that interaction.
The warning is raised if action A makes value assignments to state variables of processes which it is not supposed to interact with.

Symptoms

The action occurs at least once in the trace and assigns a value to a variable that is not contained in the set of processes the action is declared for.

• If the action is declared as a local action, the accessed variable is declared as being local to a different process.
• If the action is declared as a directed interaction, then the accessed variable is neither declared as being local to the source process nor the destination process.
• If the action is declared as an undirected interaction, then the accessed variable is declared for a process that is not contained in the set of processes that the action is supposed to interact with.

Diagnosis

• The model description contains a faulty state transformation function for this action. The action should not access this variable but a different one which is local.
• The model description contains a faulty association of the variable with its process. The action does the right job, but the variable resides in the wrong process.
• The simulator does not export the partition of state variables in a proper manner. Note that the notion of process in Traviando does not necessarily match directly with the modeling formalism that the simulator supports.

Verification and Therapy

• Check the model description for state changes associated with the particular action. Is the state transformation function as expected ? Is the association of variable V with its process as expected ? Make adjustments if necessary.
• If you like to see more details. One issue is to check if the assignments are frequent and what they are in detail. Check the report for warnings on state changes of action A to variable V being infrequent. Check the detailed trace in Traviando with the event browser to see what state changes action A to variable V does.