Re: operations on (X,Y) series

[Jean Bréfort <jean brefort normalesup org>]

Le mercredi 02 novembre 2005 à 16:51 +0100, Frederic Parrenin a écrit :
> Hi Jean,
>
> > > I would like to do various operations on (x_i,y_i) series in gnumeric,
> > > e.g.:
> > > - resampling, by simple interpolation or by integration, with a linear,
> > > spline or staircase interpolant
> > > - filtring by various methods
> > > - smoothing by various methods
> > > - fitting
> > > - principal components
> > > - Periodogram
> > > - etc.
>
> > Do you want to implement that in sheets, in graphs, or both?
> > Both sheets and graphs have already more regressions than linear.
>
> I thought in sheets.

OK, but I feel many of them would be nice in graphs too.

> There is one specific thing I would like to do in graphs.
> It is a visual correlation tool for two XY series. With that tool, you
> can stretch the X-scale of a serie to fit with another serie.
> This tool is available in a free software called AnalySeries,
> unfortunately only available on the Mac.

This might be possible with two x-axis. It might be possible to adjust
one of the axis scale (I mean automatically adjust, not by hand, of
course).

> This software also do the various math operations on XY series I
> described above. Its author (Didier Paillard) is a colleague/friend of
> me, so we could collaborate with him.
> For example, we could extract the math from AnalySeries into a library
> and use it in this gnumeric plugin.

The code must be release under the GPL.

> > I hopee we can collaborate on that. I'm interested by these features
> > too.
>
> Very good!
> I think I can understand and write the math algorithms, but I am a
> newbie in terms of UI programming.

I can probably also do some work on the maths (although I did not made
much maths during the last 30 years).