is no longer maintained. You
encouraged to switch to its
You're provided with two different ways of computing zeroth
(i.e. smoothing), first or second order derivative of the data.
- Fourier transform. The data are convoluted with
the nth order derivative of a windowing function (a Gaussian or a
box). This is done in the Fourier (frequency) domain and, therefore,
The commands are f,
smooth, take the derivative once or twice respectively.
- Cubic spline interpolation. The data are
approximated by a few carefully chosen points (markers) and
interpolated in between by a third order polynomial.