Bouncing better

During last week Jan implemented two improvements of the basic enclosure-based hybrid IVP solver. Both are based on a reduction of the set of potential states that the system may exist in, based on knowledge deduced from the hybrid IVP specification. The first one uses an explicit encoding of the states that are permissible while a particular ODE describes the dynamics of the system. The second uses the knowledge that the state immediately following a transition must satisfy the guard of the transition. 

The improvements in enclosure quality can be significant, as may be observed in the plots below. The first one shows the solution to the bouncing ball problem described previously, now simulated correctly but without using the additions:

 

The second one shows the plot resulting from simulating the same model but with the new additions:

Tests using a model of two tanks being filled and alternatively filled have indicated that the implementation may not be bug free and Jan will be concentrating on resolving this issue. Time permitting he will also address another possible addition to the solver based on dependency analysis of the ODE fields in a model.