In a previous question, I asked about how to switch between using an ODE-calculated species value, and a forced function fit. In response to some very useful interaction with the Mathworks experts (thank you Arthur), I now have a model with an ODE-calculated species value (x_ODE), a parameter whose value is set by a repeat-assignment-rule parameter (x_forced), a switch (switch_force) and a species whose value is set to either x_ODE or x_forced based upon the switch using a repeat assignment (you could use two repeat assignment rules as well, and select one active and the other not). This node (x_used) is the value used wherever needed (that is, where x_ODE would normally appear).
So I can set x_forced=sin(time) as a test case, and that works. This is a good academic exercise, but few biological functions are based upon a pure sine wave. I'd like to use a spline function set x_forced. So I'd like to use x_forced = spline(tvec, xvec, time), where tvec and xvec are vectors of time and function value, and time is the system variable time.
So, some questions: 1) Can I use vector variables within simbiology? 2) If so, is there a preload function, as in Simulink that I could use to load the vectors to fix the simbiology variable values, prior to simulation? 3) If not, can simulink call external m files, so that my repeat assignment rule would be x_forced = x_external(time) and x_external.m would be an m. function file that (on first call) reads a file, and then (and on subsequent calls) uses the data loaded from the file, and the spline function, to return the value of x at time "time"?
SBML2 only allows for parameter values that are type "double" (SBML 2, section 4.7.2). I believe that this means scalar (parameters are all scalar in Pathway Designer, for example). But biological models sometimes need vector data!