Thread: [Gnuplot-info] plotting points using a line of best fit function

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[Gnuplot-info] plotting points using a line of best fit function

From: Ben E. <bj...@ai...> - 2013-07-12 03:38:57

Hi.

I have a line of best fit calculated using the "fit" command.  I'm
trying to work out how to map new x axis values onto this function and
plot these additional points.  If I do something like:

  plot f(3) with points

then I get a straight line at y=f(3).  Is there a way to plot (3,
f(3)) instead?

Thanks, Ben

Re: [Gnuplot-info] plotting points using a line of best fit function

From: Thomas S. <t.s...@fz...> - 2013-07-12 14:06:53

Ben Elliston <bje <at> air.net.au> writes:
> I have a line of best fit calculated using the "fit" command.  I'm
> trying to work out how to map new x axis values onto this function and
> plot these additional points.  If I do something like:
> 
>   plot f(3) with points
> 
> then I get a straight line at y=f(3).  Is there a way to plot (3,
> f(3)) instead?

if you don't mind to plot 100 points at the same place
(no problem, unless you use a pen plotter):

plot "+" using (3),(f(3)) with points

Re: [Gnuplot-info] plotting points using a line of best fit function

From: Ben E. <bj...@ai...> - 2013-07-12 22:27:53

On Fri, Jul 12, 2013 at 02:06:28PM +0000, Thomas Sefzick wrote:

> if you don't mind to plot 100 points at the same place
> (no problem, unless you use a pen plotter):
> 
> plot "+" using (3),(f(3)) with points

That doesn't work. I get dozens of points along y=3, eg:

  f(x) = 2*x
  plot f(x), "+" using (0),(f(0)) with points

Ben

Re: [Gnuplot-info] plotting points using a line of best fit function

From: Thomas S. <t.s...@fz...> - 2013-07-13 11:41:29

Ben Elliston <bje <at> air.net.au> writes:

> 
> On Fri, Jul 12, 2013 at 02:06:28PM +0000, Thomas Sefzick wrote:
> 
> > if you don't mind to plot 100 points at the same place
> > (no problem, unless you use a pen plotter):
> > 
> > plot "+" using (3),(f(3)) with points
> 
> That doesn't work. I get dozens of points along y=3, eg:
> 
>   f(x) = 2*x
>   plot f(x), "+" using (0),(f(0)) with points
> 
> Ben

sorry, a typing error in the 'using' option.

this should work:

plot f(x), "+" using (0):(f(0)) with points