Re: operations on (X,Y) series

[Frederic Parrenin <parrenin ujf-grenoble fr>]

Hi,

> > > > 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.

That is true, I did not think about that.
But at least, when they are in sheets, you can plot the result on
graphs.

> > 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).

I am not sure we speak about the same thing.
I meant, strecting the X-axis by e.g. a linear by part transformation.

> > 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.

It is under the CeCill licence. It is compatible with the GNU-GPL.
More info here:
http://www.cecill.info/

Best regards,

                Frédéric