The function is estimated from n=100 noisy observations using least absolute
deviations
with a penalty on the total variation. The initial value of the smoothing
parameter is zero,
and as the smoothing parameter gets larger, the estimated function
becomes smoother (in the limit it is a straight line).
In this example, the underlying function is a sine-function.
Functions of bounded variation need not be that smooth, they may have
kinks and jumps.