Tutorial Stage 4: Manipulating graphs
On to tutorial 5
Use the Student Carbohydrate Practical as described in Tutorial 1.
Run the simulation for a few seconds to see some graphs, then pause it.
Rescale the graph of Plasma Glucose concentration. To do this, either double-click on the
y-scale of the glucose graph to toggle the 'zoomed in' or 'zoomed out' view.
Alternatively right-click (menu-click) the y-scale and specify one of the scaling options.
Note that, when zoomed in, the scale will stick around the value that was displayed
when the graphs were last rescaled. If the value changes dramatically, you can repeat the
You can scale all graphs at once using the
Graphs/Zoom in graph scales menu item.
Allow the simulation to run for a bit longer, so that some of the graph scrolls off the end
of the screen. Then pause the simulation. To see events that happened at earlier times, you can
- use the mouse scroll wheel over the graph window to scroll backwards in time
- or drag the graph left or right using the middle mouse button
- or drag left or right while simultaneously pressing the
key on the keyboard.
In the US, blood glucose is usually measured in g/L. To convert, right-click on the numeric value
of Blood Glucose on the right of the screen. Go to
Unit then select
Similarly other variables can be converted, e.g. blood gas partial pressures can be displayed in mmHg.
The time compression factor determines how fast time elapses in the simulation, relative to real
time. The slider on the right of the control bar is used to adjust this. The text next to the slider
expresses this time compression in words - e.g. '1 hour per second'. If you hover over the words,
it will also tell you the corresponding compression factor, e.g. 'x3600'.
If things go wrong while using high time compression values, please read the
entry in the FAQ about this.
The timebase can be altered - this is simply the rate at which the graph paper scrolls past. It
doesn't alter the rate at which time actually passes in the simulation, just the distance
number of pixels moved on the graph paper as each timestep of the simulation is calculated.
To alter this either right-click (menu-click) on the graph and select a value
(default is 1 pixel per frame). Alternatively select