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## Re: Solving functional nonlinear equation

 From: Jason Martin Subject: Re: Solving functional nonlinear equation Date: Mon, 28 Dec 2009 11:31:42 -0500 User-agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.1.5) Gecko/20091204 Thunderbird/3.0

```Chang,

```
You might want to try the command backend("fltk") . I noticed a long delay while using GNUPLOT with some of my graphing as well, and this was one of the solutions that worked for me. I am putting the email at the end of this email in case you missed it previously. I tried it with the sample code below, cleaned up cause I was paranoid about the denominator subtractions:
```
x=linspace(.1,1,20);y=linspace(.1,1,20);[xx,yy]=meshgrid(x,y);
for a=[1.1,1.2,1.5,2]
```
Hfxy=@(x,y)( (-1/(a^2))*(x.*y).^(1/(a-1))+(1/a)*x.^(1/(a-1))+(1/a)*y.^(1/(a-1)));
```    Dfxy=Hfxy(xx,yy);
end

and it took almost no time for the plots to be created by fltk.

Jason

On 12/28/2009 9:55 AM, Chengqi Chang wrote:
```
```Please excuse me for any confusing statement in my previous problem.
My problem is: if data of points is huge, say 100 grid points along both x
and y axes, my gnuplot renders the figure slower than I can tolerate. I
think it is the problem with gnuplot while not with octave.
Thank everyone all the same.

```
```BTW: when I firstly divided both x,y into 100 grid points, GNU plot
functions very very slow(Octave 3.2.0, GNU plot 4.3.0). I much appreciate
you help if someone can tell me how to improve its performance.

```
```
```
```
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

On 12/21/2009 8:24 PM, martin_helm wrote:

```
```>
>
>  Jason Martin-13 wrote:
```
>
```>>  Good afternoon list,
>>
>>  Please forgive me this one time error should this have been asked
>>  before, or this is in the wrong list.  If it is both, then I guess I am
>>  screwed. o.0
>>
>>  I am trying to figure out how to get clearer plots out of Octave.  I am
>>  using this m-file{http://www.thumbprintpro.com/math/fib.m}, and it is
>>  giving me the following output:
>>  http://www.thumbprintpro.com/math/OctaveOutPut.png  .  While this is
>>  adequate, it is difficult to see that this is a 3d image, and compared
>>  to this output from Matlab,
>>  http://www.thumbprintpro.com/math/MatlabOutPut.png, it is easy to see my
>>  frustration.  I am trying to relieve my stress of having to log into my
>>  schools slow remote desktops and do all of my math computations through
>>  Octave, but the output is of such quality that I cannot insert that into
>>  a report.  Also, it took 15 minutes to generate that image where Matlab
>>  took 15 seconds.  I have been looking online for a replacement plotter
>>  for use with Octave, but nothing I have found yet is working with
>>  Windows.  It could just be that I lack the necessary skills to compile
>>  some of these packages, or the knowledge of how to insert them into
>>  Octave, I am unsure.  Can someone point me in the right direction to
>>  getting opengl plots for Octave under Windows?
>>
>>  Jason
>>  _______________________________________________
>>  Help-octave mailing list
>>  https://www-old.cae.wisc.edu/mailman/listinfo/help-octave
>>
>>
```
>>
```>  To get a somewhat improved 3d feeling without the need to install an
>  you can use
>  backend("fltk")
>  before you call your script and then substitute your simple isosurface call
>  to
>
>  [F, v, c] = isosurface (x, y, z, f, 1.1, x);
>  p = patch ("Faces", F, "Vertices", v, "FaceVertexCData", c, \
>      "FaceColor", "interp", "EdgeColor", "none");
>  colormap(copper(256));
>  view(30,30)
>
>
>  Btw, jhandles gives at the moment the best results, because you can set
>  lights but
>  I have problems at the moment to install it, so I cannot directly compare.
>
>  - mh
```
>
```

```