[ubuntu-uk] Curve-fitting program or package (a gnuplot example)

[Robin Menneer]

On 3/3/07, Robert McWilliam <rmcw at allmail.net> wrote:
> On Sat, 3 Mar 2007 15:25:28 +0000
> "Robin Menneer" <robinmenneer at gmail.com> wrote:
> > Postscript.  Found (eventually) at www.xru.org.index.asp a program
> > which I used on line (on a mac), is very simple, and apart from not
> > drawing the graph, did all I wanted, including giving me the points
> > for me to draw.  It should be part of the Ubuntu package.
>
> I've just discovered that oocalc may in fact do what you want, or at
> least a bit closer to it than I thought, if you select XY plot instead
> of line graph for the plot type (the next step lets you select between
> points or lines etc.) I've put a screenshot showing the icon for XY plot
> online at http://ormiret.com/foo/x-y.png
> since oocalc doesn't seem to display the name until after you click on
> the icon.
>
I had already got in OO to that page (thanks) but I'm dealing with a
curve.  Apologies for misleading you to the curve regresssion website
is www.xuru.org.index.asp (I missed out a u).  Its non-linear
regression seems especially useful in curve smoothing.

> This just draws straight lines between the points rather than higher
> order interpolation so if you don't have many points you might have to
> implement some form of interpolation in the spread sheet (I can't find
> any interpolation formulae in oocalc).
>
> I think this is proving complicated because although you have what
> seems like a fairly simple plotting problem it is quite rare for
> someone to want this without wanting to do other data processing steps
> and so using something like octave[1], or the numeric libraries for
> their programming language of choice[2]. You've unfortunately got a
> problem that lies just beyond what is easy with oocalc (unless joining
> the dots is sufficient).
>
> [1] http://www.gnu.org/software/octave/
> [2] e.g. http://scipy.org/ for python
>
>
> ________________________________________________________
> Robert McWilliam     rmcw at allmail.net    www.ormiret.com
>
> Instructions should be read first, or not at all.
> Anything else is admitting defeat...
>
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