The model uses various forms of interaction to aid
understanding. The interactions on the DoNaLD
window work well, because they provide instant
feedback. There were issues with the exercises that
allow students to write EDEN definitions themselves.
With the tan exercise to find a side length
from another side length and an angle, the observable
names were kept simple for users to enter them
into equations (such as BC for a side length and A
for an angle). However, these identifiers may have
already been in use, for their definition caused problems
to appear with the Empirical Modelling Presentation
Environment. There was not enough time
to fix these, so the exercise has been left unimplemented.
This is a general issue though, providing
simple variable names for users increases the likelihood
that another variable of the same name is already
being used.
The sin graph transformation lesson works better, in
that users can type or copy to the input box an expression
such as y = sin(x * 3) + cos(x)
* 4; and it will be displayed on the graph. The
issues that arise here are firstly that the graph will
not update automatically. Introducing a constant
zero dummy term into the f function of the graph
solved this initially, because setting the dummy term