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Files:

controller.c: control code

data.c: saving data in mrdplot format.

display.c: animate a data file.

dynamics.c: dynamics using spring ground model

last_data: keep track of data file number for file name generation

main.h: main include file.

parameters.c: handle simulation parameters.
parameters.h

sdfast: sdfast dynamics programs

simulate: main program, run the simulation.

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