Re: [Plplot-general] surface plot questions

[David B. <stu...@gm...>]

Thanks for the tip.  If I do get that far I will post it.  Do I need to 
be a developer on this project?  Or should I just email out to the group?



On 3/21/2018 10:26 PM, Alan W. Irwin wrote:
> On 2018-03-21 18:47-0400 David Bergman wrote:
>
>> Alan,
>>
>> Thanks for the reply.  MATLAB and SCILAB functions are overloaded to 
>> allow to this.  For example the following figures were generated by 
>> such a call to surf(x,y,z), with x, y, and z each a n-by-n matrix.
>>
>> I believe this causes the function to trace curves of constant u and 
>> v, though I am not sure.  I use it to make 3-dim cardioid patterns.
>>
>> I believe the following wound work (with some mods).
>>
>> u = linspace(min,max,n);
>>
>> [U,V] = meshgrid(u,u);
>>
>> define some functions.
>>
>> X(U,V), Y(U,V), Z(U,V)
>>
>> then
>>
>> surf(X,Y,Z).
>>
>> if u and v are theta and phi in spherical coordinates, then 
>> sin(Th).*cos(Ph), sin(Th).*sin(Ph), cos(Th) would generate the unit 
>> sphere.
>
> Hi David:
>
> Cool plots!
>
> And I just realized we could produce something like those with
> <http://plplot.org/docbook-manual/plplot-html-5.13.0/plpoly3.html>.
> For an example that uses calls to plpoly3 to plot a unit sphere, see
> <http://plplot.org/examples.php?demo=18>.  It should be
> possible (but likely not trivial) to modify that example to plot 
> something more
> interesting than the unit sphere, and with a convenient API, e.g.,
>
> void
> plmeshxyz(PLINT nx, PLINT ny, PLINT nz, PLFLT_MATRIX x, PLFLT_MATRIX
> PLFLT_MATRIX z);
>
> where plmeshxyz calls plpoly3 appropriately inside.
>
> I haven't looked at the details of what would be required, but if you
> do have success with this type of approach, we will likely ask you to
> donate your work to PLplot under the LGPL so others can benefit.
>
> Alan
> __________________________
> Alan W. Irwin
>
> Astronomical research affiliation with Department of Physics and 
> Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
>
> Programming affiliations with the FreeEOS equation-of-state
> implementation for stellar interiors (freeeos.sf.net); the Time
> Ephemerides project (timeephem.sf.net); PLplot scientific plotting
> software package (plplot.sf.net); the libLASi project
> (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
> and the Linux Brochure Project (lbproject.sf.net).
> __________________________
>
> Linux-powered Science
> __________________________
>


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