Re: Trouble installing control toolbox

[Michael Noone]

OK - more attempts. I noticed some interesting things. It gives me a warning "warning: X11 DISPLAY environment variable not set". I tried loading gnuplot and then fltk, and the latter operation caused an error. Finally, after switching to fltk and doing a close all, I caused Octave to crash.

I checked with Cygwin and I have "libfltk 1.1" installed already.

Any of this mean anything to anybody? :) I'm including the full output below, sorry for the huge paste. Thanks!!

$ octave
...
warning: X11 DISPLAY environment variable not set
octave:1> pkg load control
octave:2> pkg load gnuplot
octave:3> pkg load fltk
error: package fltk is not installed
error: called from:
error:   /usr/share/octave/3.6.2/m/pkg/pkg.m at line 2134, column 11
error:   /usr/share/octave/3.6.2/m/pkg/pkg.m at line 401, column 7
octave:3> A = tf(1, [1 2 3])

Transfer function 'A' from input 'u1' to output ...

            1
 y1:  -------------
      s^2 + 2 s + 3

Continuous-time model.
octave:4> bode(A)
+-------------------------------Bode Diagram of A------------------------------+
|    Magnitude [dB]                                                            |
|     -10 ++----+---+-+-+-+++++-----+---+--+-++-++++-----+--+--+-++-++++       |
|     -20 ++..................+.....+++++++........+..................++       |
|     -30 ++..............................++++++......................++       |
|     -40 ++...................................+++++++................++       |
|     -50 ++.........................................+++++++..........++       |
|     -60 ++...............................................++++++.....++       |
|     -70 ++..................+....................+............++++++++       |
|     -80 +-1---+---+-+-+-+++++0----+---+--+-++-++++1----+--+--+-++-++++2      |
|        10                  10                   10                  10       |
|   Phase [deg]                                                                |
|       0 ++----+---+-+-+-+++++-----+---+--+-++-++++-----+--+--+-++-++++       |
|     -20 ++.....++++++++++++++....................+..................++       |
|     -60 ++.................+++++....................................++       |
|     -80 ++.....................+++..................................++       |
|    -100 ++.......................++++...............................++       |
|    -140 ++..........................+++++...........................++       |
|    -160 ++..................+...........+++++++++++++++.............++       |
|    -180 +-1---+---+-+-+-+++++0----+---+--+-++-++++1----+--+--+-++-++++2      |
|        10                  10                   10                  10       |
+------------------------------------------------------------------------------+
octave:5> graphics_toolkit
ans = gnuplot
octave:6> close all
octave:7> graphics_toolkit fltk
octave:8> bode(A)
Can't open display:
terminate called after throwing an instance of 'std::length_error'
  what():  basic_string::_S_create
Aborted

On Thu, Dec 13, 2012 at 5:57 PM, Benjamin Abbott <address@hidden> wrote:

On Dec 13, 2012, at 8:22 PM, Michael Noone <address@hidden> wrote:

> Hi Alexander - we're getting somewhere now! I installed gnuplot. However, the graph I'm getting is rather ugly... I tried switching to fltk and it did not change the output.

Try ...

close all
graphics_toolkit fltk
plot (rand (3))

... And you'll either get an error or will get an fltk plot.

If you'd like to use gnuplot instead, try ...

close all
graphics_toolkit gnuplot
setenv GNUTERM x11
plot (rand (3))

... And you'll either get a gnuplot window or an error.

Ben