The program 'rms' in TISEAN is a pepculiar one. I really doesn't 'do' anything. It is in the 'Utilities' category on the TISEAN documentation page. Those functions are there only to help the user better utylise the package and are of not much use.

This program computes: mean, standard deviation, smallest, largest and then allows to subtract the average or subtract mean - normalise to unit variance. Let us discuss what functions do this job in Octave:
  1. The mean can be obtained in GNU Octave using 'mean'.
  2. The standard deviation can be obtained in Octave using 'std'
  3. The smallest can item can be obtained by using 'min'
  4. The largest item can be obtained by using 'max'
  5. Subtracting the mean 'vec - mean(vec)'
  6. Subtracting the average 'vec - sum (vec) / rows (vec)'

Thus there is no need to port 'rms' from TISEAN.
