Order of events

This is only an issue for discrete-time models, as for a continuous time model it is always “now”.

Consider discrete time model that compares to data. There will be some series of “updates” then a comparison to data, then we repeat until we reach the end of the data. The order of events as we move from time = t0 to to time = t0 + dt is:

Update

1. Reset any variables that use zero_every
2. Read from variables
3. Look up interpolation (using t0)
4. Evaluate all assignments (therefore with time = t0 and all variables having the value at the beginning of the step)
5. Write out new values of state
6. Update time to t0 + dt

Compare

1. Read from variables
2. Look up interpolation (using t0 + dt)
3. Compare to data