On 28/12/08 22:11, Nicolas Le novère wrote: > Catherine Lloyd wrote: > >> However, we now face a different problem... Although we can easily >> describe the switches as piece-wise equations, if we define a single >> variable more than once in a CellML model the simulation tools tell >> us that the model is over constrained. >> >> For example in this case we already have a differential equation >> describing the change in mass over time, and then we have a second >> equation placing a condition on mass: > > No, no. Events are not assignment rules. In SBML as well, you could > not have a rate rule and an assignment rule on mass. Events are > discontinuous processes taking place in between simulation iterations. > I think this is just a missing concept in CellML. It exists in > simulators like XPP and GENESIS, used for neuronal simulations (e.g. > to reset voltage in spiking neurons). > > (To be absolutely frank, the existence of events as part of the core > SBML has been challenged many times. But I think we can now see why > they are needed :-))
Indeed, I also think this is a missing feature in CellML, and perhaps one that should be included in version 1.2? For the record, there has been a tracker item created for this issue; see https://tracker.physiomeproject.org/show_bug.cgi?id=1543 Jonathan _______________________________________________ cellml-discussion mailing list [email protected] http://www.cellml.org/mailman/listinfo/cellml-discussion
