A couple questions. One: is there a defined way in CellML to find the independent variables? The spec says (about 'initial_value'):

This attribute provides a convenient means for specifying the value of a scalar real variable when all independent variables in the model have a value of 0.0. Independent variables are those whose values do not depend on others. >From that definition, it would seem that if you defined 'pi' in your model, the initial value would apply when pi was equal to 0. But more generally, if you have a single equation in your model: u = sin(t) That's a single equation with two variables--how do you decide that you want to vary t and not u? Do you just apply heuristics, so if you see 'dx/dy' you assume y is the independent variable? Is it part of what you do *with* a CellML model, that you present the user with t and u as possible options, and they pick one? My second question is a bit simpler: is there a way to define a delay equation in CellML and if so, how do you do it? (A delay being something like 'x, 2 seconds ago'.) -Lucian _______________________________________________ cellml-discussion mailing list cellml-discussion@cellml.org http://lists.cellml.org/mailman/listinfo/cellml-discussion