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Groups > comp.graphics.apps.gnuplot > #3598

Re: set range for second independent variable in special file '++'

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Karl Ratzsch wrote:

> Am 26.03.2017 um 21:30 schrieb Ethan A Merritt:
>> Karl Ratzsch wrote:
>>> Hm, there are many, i think. The special filename "++" at the moment
>>> always directly maps the second independent variable to the y axis,
>>> but it could easily be meant to be sth else. Of course one can scale
>>> the values to the wanted sampling range in the "using" specifier,
>>> but you need a number of additional variables and it makes the
>>> script hard to read.
>> 
>> That much is a trivial change and I agree it is an improvement.
>> 
>> So as of today's CVS for the development version, '++' uses urange
>> and vrange for sampling rather than using xrange and yrange.
>> This does not by itself allow you to refer to the sampled variables
>> as "u" and "v" however, you'll still have to refer to $1 and $2.
>> 
>> I know of one minor downside to this change.
>> Currently you can't set u or v to log-scale, so with this change
>> you won't get nonlinear sampling on '++' even after "set log xy".
>> That can be added later.
> 
> Not much of a downside, but what about "+" ? Will it use trange now?
> That's a bit strong, re backwards compatibility. ?

Good question.

Although the syntax required is not quite the same as for '++'
you can already effectively do that like this:

    set xrange [1:100]
    plot sample [t=10:20] '+' using (t):(sin(t))

You are right that it could default to using trange rather than xrange
if trange has been set previously.

Backwards compatibility would be a concern, but ... [thinking as I type]
trange isn't set by default since at the moment it is ignored unless
you are in polar or parametric mode.  So the conflict with older
syntax is less than it might be.  I don't know whether or not it's a
good idea since it doesn't actually gain you anything you can't do 
already (unlike the '++' case).

Let's defer that idea for now.  There are some autoscaling problems lurking
around the use of t/u/v for sampling, particularly for log scale x or y.
I want to sort those out first.

    Ethan

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Thread

set range for second independent variable in special file '++' Karl Ratzsch <mail.kfr@gmx.net> - 2017-03-20 08:36 +0100
  Re: set range for second independent variable in special file '++' Ethan A Merritt <EAMerritt@gmail.com> - 2017-03-20 09:39 -0700
    Re: set range for second independent variable in special file '++' Karl Ratzsch <mail.kfr@gmx.net> - 2017-03-20 18:56 +0100
      Re: set range for second independent variable in special file '++' Ethan A Merritt <sfeam@users.sourceforge.net> - 2017-03-20 12:36 -0700
        Re: set range for second independent variable in special file '++' Ethan A Merritt <sfeam@users.sourceforge.net> - 2017-03-20 12:38 -0700
          Re: set range for second independent variable in special file '++' Karl Ratzsch <mail.kfr@gmx.net> - 2017-03-24 13:15 +0100
            Re: set range for second independent variable in special file '++' Ethan A Merritt <EAMerritt@gmail.com> - 2017-03-26 12:30 -0700
              Re: set range for second independent variable in special file '++' Karl Ratzsch <mail.kfr@gmx.net> - 2017-03-27 03:35 +0200
                Re: set range for second independent variable in special file '++' Ethan A Merritt <EAMerritt@gmail.com> - 2017-03-26 23:00 -0700
                Re: set range for second independent variable in special file '++' Karl Ratzsch <mail.kfr@gmx.net> - 2017-03-27 22:15 +0200
                Re: set range for second independent variable in special file '++' Karl Ratzsch <mail.kfr@gmx.net> - 2017-04-02 19:02 +0200
                Re: set range for second independent variable in special file '++' Ethan A Merritt <EAMerritt@gmail.com> - 2017-04-05 22:09 -0700

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