Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.graphics.apps.gnuplot > #3593

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

Show all headers | View raw

Am 20.03.2017 um 20:38 schrieb Ethan A Merritt:
> Ethan A Merritt wrote:
>> Karl Ratzsch wrote:
>>> It seems I can only specify one independent variable with range for
>>> '++'. Is that so?
>>
>> Yes, but...
>> That's mostly because it's not clear how one could use it.
>> If you have an example of a type of plot that this would allow,
>> I'd be happy to look into adding it.

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.

Any kind of circular object would be an example, or generally a 3D plot
with a coordinate transformation.

Parametric mode is an alternative, but I think I'm not the only one who
tries to avoid it because of the ugly syntax. ;-)

>>> I want to plot a ribbon wound on a cylindrical core (not actually such a
>>> boring one, but nevermind).

>> set parametric
>> splot radius*sin(u), radius*cos(u), (rise*u-v)
>> set isosample 100, 10
>  set hidden3d
>  replot

Here's the actual plot I wanted to make, now using parametric mode. It's
a short electric coil with a large volume of constant magnetic flux density.

a=-0.012   # zero for even coil width
n=9.	   # windings
l=20.;r=8. # lenght and radius
d=0.5      # distance between windings

#PRIVALOV, DVINSKIKH, VIETH, 1996, JMagRes A, 123, 157-160
k(n,a) = l/2 / (pi*n + a*pi**2*n**2) # normalise height to l
s(th,a) = k(n,a) * (th + a*th*abs(th)) # conductor center
h1(th,a) = (s(th+2*pi,a) + s(th,a))/2  - d/2 # edge 1
h2(th,a) = (s(th-2*pi,a) + s(th,a))/2  + d/2 # edge 2

set param
set xr[-r:r]; set yr[-r:r]
set urange [-n*pi:n*pi]
set vrange [0:1]
set isosample 1000,8
set hidden3d
set view equal xyz
set xyplane 0
splot r*cos(u),r*sin(u),h1(u,a)*v/2 + h2(u,a)*(1-v)/2

Back to comp.graphics.apps.gnuplot | Previous | Next — Previous in thread | Next in thread | Find similar

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

csiph-web