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Parametrized Figures and Animation Frames

As already mentioned, variables may be used to clarify the logical structure of a figure. The way the inscribed rectangle figure was implemented makes it easy to change the width of the rectangle. When a figure is complicated, judicious use of variables makes the figure flexible. The sample file depicting upper rectangles for the sin function is an example; to change the number of rectangles, one need change only a single number in the preamble. To change the integrand to a different increasing function also requires just one change in the preamble. (Labels' text must still be changed individually.)

If a figure depends suitably upon a collection of parameters, then a loop can be used to draw the entire figure for multiple values of the parameters, yielding successive ``snapshots'' of the figure as time progresses.4 In the sample files is a simple example, the cycloids traced by a rolling wheel. Other possibilities are to solve a planar ODE for varying lengths of time (illustrating the flow), or to plot solutions of a $ (1+1)$-dimensional PDE (for example, to depict heat flow or wave motion).


next up previous
Next: Summary of ePiX Objects Up: More Advanced Uses of Previous: Finite Sums and Other
hwang
2002-06-06