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

[Robin Menneer]

On 2/24/07, Robin Menneer <robinmenneer at gmail.com> wrote:
>
>
>
> On 2/24/07, Andrew Price <andy at andrewprice.me.uk> wrote:
> > On 24/02/07 17:54, Robin Menneer wrote:
> > > I have a problem with fitting a curve to some data and would like help
> > > please.  The data are:
> > > x=375, 375, 375, 355, 315, 268,195, 110, 0
> > > y=2500, 2150, 1920, 1600, 1250, 936, 624, 312, 0
> > > I need a program that will draw a line of best fit (for me to print)
> > > according to different parameters,, especially log and power and find
> the
> > > best for me, and give me the equation for it.
> >
> > gnuplot seems like a good tool for this job. It's a tool with a wide
> > range of options and commands so it can seem a bit daunting to use it
> > for the first time (I should know, I used it for the first time today :))
> >
> > Anyway, here's an example of how to do it (I'm assuming you've already
> > installed the gnuplot package):
> >
> > Put your X and Y data in a text file in columns like:
> >
> > 375    2500
> > 375    2150
> > 375    1920
> > 355    1600
> > 315    1250
> > 268    936
> > 195    624
> > 110    312
> > 0      0
> >
> > Then open a terminal and go to the directory with the data file in it
> > and run gnuplot:
> >
> > $ cd /path/tomy/datafile/dir/
> > $ gnuplot
> >
> > Once you're in the gnuplot "shell", tell it to plot columns 1 and 2 as x
> > and y respectively, giving the curve a title:
> >
> > gnuplot> plot "mydatafile.dat" using 1:2 title 'Data' smooth csplines
> >
> > Removing "smooth csplines" would make gnuplot plot each individual point
> > without a curve, replacing "csplines" with "unique" joins the dots. A
> > whole range more options can be found in the documentation [1].
> >
> > If you want to plot the data to an image file, precede the plot command
> > with something like these two commands:
> >
> > gnuplot> set terminal png
> > gnuplot> set output 'mygraph.png'
> >
> > For a list of other output file types, just type 'set terminal' without
> > an option.
> >
> > (Don't let the command line nature of this daunt you, it's pretty simple
> > and tutorials like [2] and demos like [3] show you how powerful it can be)
> >
> > [1] http://www.gnuplot.info/docs/gnuplot.html
> > [2] http://www.duke.edu/~hpgavin/gnuplot.html
> > [3] http://www.gnuplot.info/demo/simple.html
> >
> > Hope this helps.
> >
> > --
> > Andy Price
> > IRC: welshbyte
> > http://andrewprice.me.uk
>
> Thanks - it does look daunting and I'll need a quiet afternoon  (or day ?)
> to puzzle my way through it.  Many Thanks
> Robin
>
> > --
> > ubuntu-uk at lists.ubuntu.com
> > https://lists.ubuntu.com/mailman/listinfo/ubuntu-uk
> > https://wiki.kubuntu.org/UKTeam/
> >
>
>
I've spent all day looking at loading gnuplot and fityk as well as a
dozen of other curvefitting packages on the web including xplot and
have found none that are simple enouigh for me to install without my
risking messing my memory/files up.  Has nobody cleaned up a
curvefiitting program in Ubuntu sufficiently for a thickie to run ?