User manual for Iode - Department of Mathematics

14 CHAPTER 1. DIRECTION FIELDS
Variable names should consist of only one letter, to avoid the risk of
conflicting with Iode’s internal variables.
Options menu
• Clicking on figure...: lets you choose what happens when you leftclick
on the plot. The four possibilities are
– plots solution through click point (this is the default action),
– zooms in on click point,
– zooms out on click point,
– recenters figure on click point.
Incidentally, the time taken by the “zoom out” operation grows exponentially
with the number of clicks because zooming out requires a
recomputation of existing solutions over the new (larger) domain. If
the domain doubles in size when you zoom out, then recomputing the
solutions will take twice as long as previously because the number of
steps has to be doubled also. If you zoom out again, the time needed
to recompute all solutions doubles again, and so on.
• Change zoom factors: this only matters if you have set the clicking
option to “zoom”.
• Clear plot: to erase all curves.
• Refresh plot: try this if Matlab didn’t update your plot properly.
This sometimes happens when other windows partially cover a Matlab
window.