GNU Octave AND plots
====================

I use the GNU  Octave [1] sometimes. Now is the rare time  when I have been
using it almost all time.

I'm using is  for easy programming of thing that  use matrix and vector
operations. And  sometimes it  is necessary to  produce some  output in
form of graphs and plots. And there are issues.

In the  past the  Octave used the  Gnuplot [2] as  it only  backend for
plots. It  worked well in  the UNIX/X11 environments (including  so old
platforms like  the IRIX 5.x)  and it worked  best when the  Octave was
CLI-only program.

The  Gnuplot works  in many  situations -  on Tektronics  terminals, on
MS-DOS, on  X11 and  it even  supports the SVGALIB  output (it  you not
aware about it - it's an old  Linux library which used direct access to
computer  hardware  to show  graphics  -  that  is  when it  hung  then
it  rendered  the  whole  computer uncontrollable;  but  it  worked  on
"text-only" Linux systems without the X11 installed).

It was  funny that Gnuplot worked  quite well with the  SVGALIB but the
Octave  + Gnuplot  combination  did  not. Later  the  Octave got  other
possibilities  to plot  graphs. The  modern one  oses a  FLTK-base plot
window as a Gnuplot alternative. And it works. Well, mostly.

At work I have to use a  Win10 computer. I have ahd installed the Linux
Subsystem (the Ubuntu  on Windows, that is) and it  less or more works.
Gtk+ applications works,  Qt application, too. I have here  the Git and
other tools so I use it more  often than native Octave or native Vim on
the Win10. The octave computes well here.  It even work in the GUI mode
well here  (from the  version 4.x  it has  a rather  nice Qt  GUI; from
version 5.x is also works well).

Now I  have needed not  only to compute  numbers but also  to visualize
them.  And the  troubles  have become.  The only  result  was an  empty
window.  So I  changed the  graphics_terminal value  to "gnuplot".  The
Octave printed an  error message on start and showed  and empty window.
Then I tried the  "fltk". The result was the same.  My octave says that
is has no other options.

Then I  accidentally ran the computation  in CLI version of  Octave. At
the end of computation it showed  proper plot window! The I changed the
terminal to "gnuplot".  It also worked,.. But in the  GUI mode it still
does not work.

Of  course, the  native  Octave  for windows  work  without issues  (it
complies about some OpenGL problems but at the end it works).

By the way on the Linux, even on  the PPC64 Linux, it jsut works in any
mode. The only  problem is on the  oldest RaspBerry Pi -  there is just
fails when is  sees a firs floating point instruction.  It does this on
the official Raspbian so I see solution except ceasing of such tryings.

On the IRIX there is no GUI version  of the Octave (no one on the Earth
has been brave enough  to port the Octave 3.0 or newer  to the IRIX) so
such problems do  not exist here. The Octave 2.x  work with the Gnuplot
3.5 as expected.  Some thing are thus not possible  here but hey, these
machines are at least  15 years old (my newest one is  22 years old) so
complicated thing would be too slow on them.


References:

[1] http://octave.org
[2] http://gnuplot.info

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