octave:2> 
octave:2> 
octave:2> 
octave:16> 

y2 = x.^2;^[[201~octave:16> 
octave:16> 
octave:16> 
octave:16> 
octave:16> x = -10:0.1:10;
y = x.^3;
y2 = x.^2;
octave:19> size(y)
ans =

     1   201

octave:20> size(x)
ans =

     1   201

octave:21> plot(x, y)
octave:22> plot(x, y2)
octave:23> hold on
octave:24> plot(x, y)
octave:25> figure
octave:26> plot(x, y)
octave:27> close all
octave:28> figure
octave:29> plot(x, y)
octave:30> xlabel('x axis')
octave:31> ylabel('y axis')
octave:32> ylabel('y axis! yay!')
octave:33> ylabel('y axis! yay! more letters')
octave:34> title('a plot of a cubic')
octave:35> grid on
octave:36> legend('x^3')
octave:37> hold on
octave:38> close all
octave:39> 
^[[201~octave:39> 
octave:39> 
octave:39> 
octave:39> 
octave:39> hold on;    % plotting more than 1 plot on 1 figure rather than overwriting
 

plot(x, y, 'DisplayName', 'x^3');
plot(x, y2, 'DisplayName', 'x^2');

hold off;

xlabel 'x axis';
ylabel 'y axis';
title 'Example 1';
xlim([-10 10]);
ylim([-10 10]);
% axis([-10 10 -10 10]);
grid on;
legend show;                             % 'DisplayName does thisi
octave:50> close all
octave:51> help axis
'axis' is a function from the file /usr/share/octave/7.3.0/m/plot/appearance/axis.m

 -- axis ()
 -- axis ([X_LO X_HI])
 -- axis ([X_LO X_HI Y_LO Y_HI])
 -- axis ([X_LO X_HI Y_LO Y_HI Z_LO Z_HI])
 -- axis ([X_LO X_HI Y_LO Y_HI Z_LO Z_HI C_LO C_HI])
 -- axis (OPTION)
 -- axis (OPTION1, OPTION2, ...)
 -- axis (HAX, ...)
 -- LIMITS = axis ()
     Set axis limits and appearance.

     The argument LIMITS should be a 2-, 4-, 6-, or 8-element vector.
     The first and second elements specify the lower and upper limits
     for the x-axis.  The third and fourth specify the limits for the
     y-axis, the fifth and sixth specify the limits for the z-axis, and
     the seventh and eighth specify the limits for the color axis.  The
     special values '-Inf' and 'Inf' may be used to indicate that the
     limit should be automatically computed based on the data in the
     axes.

     Without any arguments, 'axis' turns autoscaling on.

     With one output argument, 'LIMITS = axis' returns the current axis
     limits.

     The vector argument specifying limits is optional, and additional
     string arguments may be used to specify various axis properties.

     The following options control the aspect ratio of the axes.

     "equal"
          Force x-axis unit distance to equal y-axis (and z-axis) unit
          distance.

     "square"
          Force a square axis aspect ratio.

     "vis3d"
          Set aspect ratio modes ("DataAspectRatio",
          "PlotBoxAspectRatio") to "manual" for rotation without
          stretching.

     "normal"
     "fill"
          Restore default automatically computed aspect ratios.

     The following options control the way axis limits are interpreted.

     "auto"
     "auto[xyz]"
     "auto [xyz]"
          Set nice auto-computed limits around the data for all axes, or
          only the specified axes.

     "manual"
          Fix the current axes limits.

     "tight"
          Fix axes to the limits of the data.

     "image"
          Equivalent to "tight" and "equal".

     The following options affect the appearance of tick marks.

     "tic"
     "tic[xyz]"
     "tic [xyz]"
          Turn tick marks on for all axes, or turn them on for the
          specified axes and off for the remainder.

     "label"
     "label[xyz]"
     "label [xyz]"
          Turn tick labels on for all axes, or turn them on for the
          specified axes and off for the remainder.

     "nolabel"
          Turn tick labels off for all axes.

     Note: If there are no tick marks for an axes then there can be no
     labels.

     The following options affect the direction of increasing values on
     the axes.

     "xy"
          Default y-axis, larger values are near the top.

     "ij"
          Reverse y-axis, smaller values are near the top.

     The following options affects the visibility of the axes.

     "on"
          Make the axes visible.

     "off"
          Hide the axes.

     If the first argument HAX is an axes handle, then operate on this
     axes rather than the current axes returned by 'gca'.

     Example 1: set X/Y limits and force a square aspect ratio

          axis ([1, 2, 3, 4], "square");

     Example 2: enable tick marks on all axes, enable tick mark labels
     only on the y-axis

          axis ("tic", "labely");

     See also: xlim, ylim, zlim, caxis, daspect, pbaspect, box, grid.

Additional help for built-in functions and operators is
available in the online version of the manual.  Use the command
'doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at https://www.octave.org and via the help@octave.org
mailing list.
octave:52> 

d2 = cos(t);^[[201~octave:52> 
octave:52> 
octave:52> 
octave:52> 
octave:52> t = 0:.1:10;
d1 = sin(t);
d2 = cos(t);
octave:55> figure
octave:56> 
^[[200~hold on;
plot(t, d1);
plot(t, d2);
hold off;^[[201~octave:56> 
octave:56> 
octave:56> 
octave:56> 
octave:56> hold on;
plot(t, d1);
plot(t, d2);
hold off;
octave:60> 
^[[200~title 'Trig Functions';^[[201~octave:60> 
octave:60> 
octave:60> 
octave:60> 
octave:60> title 'Trig Functions';
octave:61> 
^[[200~xlabel 'time (\mu)s';^[[201~octave:61> 
octave:61> 
octave:61> 
octave:61> 
octave:61> xlabel('time (\mu)s');
octave:62> ylabel('voltage')
octave:63> legend('sin', 'cos')
octave:64> close all
octave:65> figure
octave:66> 
octave:66> 
octave:66> 
octave:66> 
octave:66> 
octave:66> plot(t, d1, 'b-.', t, d2, 'rp');
octave:67> 

^[[200~title 'Trig Functions';
xlabel 'time ($\mu$s)' Interpreter latex
ylabel voltage;
legend('sin', 'cos');
xticks(0:pi/2:10);
xticklabels({'0', '\pi/2', '\pi', '3\pi/2', '2\pi', '5\pi/2', '3\pi'});^[[201~octave:6
7> 
octave:67> 
octave:67> 
octave:67> 
octave:67> title 'Trig Functions';
xlabel 'time ($\mu$s)' Interpreter latex
ylabel voltage;
legend('sin', 'cos');
xticks(0:pi/2:10);
xticklabels({'0', '\pi/2', '\pi', '3\pi/2', '2\pi', '5\pi/2', '3\pi'});
sh: 1: dvipng: not found
warning: latex_renderer: a run-time test failed and the 'latex' interpreter has been d
isabled.
warning: called from
    __axis_label__ at line 36 column 6
    xlabel at line 59 column 8

octave:73> title 'Trig Functions';
xlabel 'time ($\mu$s)' Interpreter latex
ylabel voltage;
legend('sin', 'cos');
xticks(0:pi/2:10);
xticklabels({'0', '\pi/2', '\pi', '3\pi/2',
octave:73> 
^[[200~xticks(0:pi/2:10);^[[201~octave:73> 
octave:73> 
octave:73> 
octave:73> 
octave:73> xticks(0:pi/2:10);
octave:74> 
^[[200~xticklabels({'0', '\pi/2', '\pi', '3\pi/2', '2\pi', '5\pi/2', '3\pi'});^[[201~o
ctave:74> 
octave:74> 
octave:74> 
octave:74> 
octave:74> xticklabels({'0', '\pi/2', '\pi', '3\pi/2', '2\pi', '5\pi/2', '3\pi'});
octave:75> close all
octave:76> figure
octave:77> subplot(2, 1, 1)
octave:78> 
^[[200~octave:75> close all^[[201~octave:78> 
octave:78> 
octave:78> 
octave:78> 
octave:78> octave:75> close all
octave:78> figure
octave:79> subplot(2, 1, 1)
octave:80> plot(t, d1)
octave:81> hold on
octave:82> plot(t, d2)
octave:83> title('an ordinary plot')
octave:84> subplot(2, 1, 2)
octave:85> 
octave:85> 
octave:85> 
octave:85> 
octave:85> 
octave:85> plot(t, d1, 'b-.', t, d2, 'rp');
title 'Customized plot';
octave:87> close all
octave:88> figure
octave:89> stem(t, d1)
octave:90> hold on
octave:91> scatter(t, d2)
octave:92> close all
octave:93> 
^[[200~t = linspace(0,10*pi);^[[201~octave:93> 
octave:93> 
octave:93> 
octave:93> 
octave:93> t = linspace(0,10*pi);
octave:94> figure
octave:95> plot3(sin(t), cos(t), t)
octave:96> zlabel('t')
octave:97> zlabel('tttttttttttttttttttttttttttttttttttt')
octave:98> title('a helix! in space!')
octave:99> text(0, 0, 0, 'origin')
octave:100> close all
octave:101> 
^[[200~a1 = -2:0.25:2;
b1 = a1;
[A1, B1] = meshgrid(a1);
F = A1.*exp(-A1.^2-B1.^2);^[[201~octave:101> 
octave:101> 
octave:101> 
octave:101> 
octave:101> a1 = -2:0.25:2;
b1 = a1;
[A1, B1] = meshgrid(a1);
F = A1.*exp(-A1.^2-B1.^2);
octave:105> A1
A1 =

 Columns 1 through 9:

  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0
  -2.0000  -1.7500  -1.5000  -1.2500  -1.0000  -0.7500  -0.5000  -0.2500        0

 Columns 10 through 17:

   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000
   0.2500   0.5000   0.7500   1.0000   1.2500   1.5000   1.7500   2.0000

octave:106> B1
B1 =

 Columns 1 through 9:

  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000
  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500
  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000
  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500
  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000
  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500
  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000
  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500
        0        0        0        0        0        0        0        0        0
   0.2500   0.2500   0.2500   0.2500   0.2500   0.2500   0.2500   0.2500   0.2500
   0.5000   0.5000   0.5000   0.5000   0.5000   0.5000   0.5000   0.5000   0.5000
   0.7500   0.7500   0.7500   0.7500   0.7500   0.7500   0.7500   0.7500   0.7500
   1.0000   1.0000   1.0000   1.0000   1.0000   1.0000   1.0000   1.0000   1.0000
   1.2500   1.2500   1.2500   1.2500   1.2500   1.2500   1.2500   1.2500   1.2500
   1.5000   1.5000   1.5000   1.5000   1.5000   1.5000   1.5000   1.5000   1.5000
   1.7500   1.7500   1.7500   1.7500   1.7500   1.7500   1.7500   1.7500   1.7500
   2.0000   2.0000   2.0000   2.0000   2.0000   2.0000   2.0000   2.0000   2.0000

 Columns 10 through 17:

  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000  -2.0000
  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500  -1.7500
  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000  -1.5000
  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500  -1.2500
  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000  -1.0000
  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500  -0.7500
  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000  -0.5000
  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500  -0.2500
        0        0        0        0        0        0        0        0
   0.2500   0.2500   0.2500   0.2500   0.2500   0.2500   0.2500   0.2500
   0.5000   0.5000   0.5000   0.5000   0.5000   0.5000   0.5000   0.5000
   0.7500   0.7500   0.7500   0.7500   0.7500   0.7500   0.7500   0.7500
   1.0000   1.0000   1.0000   1.0000   1.0000   1.0000   1.0000   1.0000
   1.2500   1.2500   1.2500   1.2500   1.2500   1.2500   1.2500   1.2500
   1.5000   1.5000   1.5000   1.5000   1.5000   1.5000   1.5000   1.5000
   1.7500   1.7500   1.7500   1.7500   1.7500   1.7500   1.7500   1.7500
   2.0000   2.0000   2.0000   2.0000   2.0000   2.0000   2.0000   2.0000

octave:107> F
F =

 Columns 1 through 9:

  -0.0007  -0.0015  -0.0029  -0.0048  -0.0067  -0.0078  -0.0071  -0.0043        0
  -0.0017  -0.0038  -0.0074  -0.0123  -0.0172  -0.0200  -0.0182  -0.0110        0
  -0.0039  -0.0086  -0.0167  -0.0276  -0.0388  -0.0450  -0.0410  -0.0248        0
  -0.0077  -0.0172  -0.0331  -0.0549  -0.0771  -0.0896  -0.0816  -0.0492        0
  -0.0135  -0.0301  -0.0582  -0.0964  -0.1353  -0.1572  -0.1433  -0.0864        0
  -0.0209  -0.0466  -0.0901  -0.1493  -0.2096  -0.2435  -0.2219  -0.1338        0
  -0.0285  -0.0637  -0.1231  -0.2041  -0.2865  -0.3328  -0.3033  -0.1829        0
  -0.0344  -0.0769  -0.1485  -0.2461  -0.3456  -0.4014  -0.3658  -0.2206        0
  -0.0366  -0.0818  -0.1581  -0.2620  -0.3679  -0.4273  -0.3894  -0.2349        0
  -0.0344  -0.0769  -0.1485  -0.2461  -0.3456  -0.4014  -0.3658  -0.2206        0
  -0.0285  -0.0637  -0.1231  -0.2041  -0.2865  -0.3328  -0.3033  -0.1829        0
  -0.0209  -0.0466  -0.0901  -0.1493  -0.2096  -0.2435  -0.2219  -0.1338        0
  -0.0135  -0.0301  -0.0582  -0.0964  -0.1353  -0.1572  -0.1433  -0.0864        0
  -0.0077  -0.0172  -0.0331  -0.0549  -0.0771  -0.0896  -0.0816  -0.0492        0
  -0.0039  -0.0086  -0.0167  -0.0276  -0.0388  -0.0450  -0.0410  -0.0248        0
  -0.0017  -0.0038  -0.0074  -0.0123  -0.0172  -0.0200  -0.0182  -0.0110        0
  -0.0007  -0.0015  -0.0029  -0.0048  -0.0067  -0.0078  -0.0071  -0.0043        0

 Columns 10 through 17:

   0.0043   0.0071   0.0078   0.0067   0.0048   0.0029   0.0015   0.0007
   0.0110   0.0182   0.0200   0.0172   0.0123   0.0074   0.0038   0.0017
   0.0248   0.0410   0.0450   0.0388   0.0276   0.0167   0.0086   0.0039
   0.0492   0.0816   0.0896   0.0771   0.0549   0.0331   0.0172   0.0077
   0.0864   0.1433   0.1572   0.1353   0.0964   0.0582   0.0301   0.0135
   0.1338   0.2219   0.2435   0.2096   0.1493   0.0901   0.0466   0.0209
   0.1829   0.3033   0.3328   0.2865   0.2041   0.1231   0.0637   0.0285
   0.2206   0.3658   0.4014   0.3456   0.2461   0.1485   0.0769   0.0344
   0.2349   0.3894   0.4273   0.3679   0.2620   0.1581   0.0818   0.0366
   0.2206   0.3658   0.4014   0.3456   0.2461   0.1485   0.0769   0.0344
   0.1829   0.3033   0.3328   0.2865   0.2041   0.1231   0.0637   0.0285
   0.1338   0.2219   0.2435   0.2096   0.1493   0.0901   0.0466   0.0209
   0.0864   0.1433   0.1572   0.1353   0.0964   0.0582   0.0301   0.0135
   0.0492   0.0816   0.0896   0.0771   0.0549   0.0331   0.0172   0.0077
   0.0248   0.0410   0.0450   0.0388   0.0276   0.0167   0.0086   0.0039
   0.0110   0.0182   0.0200   0.0172   0.0123   0.0074   0.0038   0.0017
   0.0043   0.0071   0.0078   0.0067   0.0048   0.0029   0.0015   0.0007

octave:108> figure
octave:109> surf(A1, B1, F)
octave:110> figure
octave:111> mesh(A1, B1, F)
octave:112> close all
octave:113> help quiver
'quiver' is a function from the file /usr/share/octave/7.3.0/m/plot/draw/quiver.m

 -- quiver (U, V)
 -- quiver (X, Y, U, V)
 -- quiver (..., S)
 -- quiver (..., STYLE)
 -- quiver (..., "filled")
 -- quiver (HAX, ...)
 -- H = quiver (...)

     Plot a 2-D vector field with arrows.

     Plot the (U, V) components of a vector field at the grid points
     defined by (X, Y).  If the grid is uniform then X and Y can be
     specified as vectors and 'meshgrid' is used to create the 2-D grid.

     If X and Y are not given they are assumed to be '(1:M, 1:N)' where
     '[M, N] = size (U)'.

     The optional input S is a scalar defining a scaling factor to use
     for the arrows of the field relative to the mesh spacing.  A value
     of 1.0 will result in the longest vector exactly filling one grid
     square.  A value of 0 disables all scaling.  The default value is
     0.9.

     The style to use for the plot can be defined with a line style
     STYLE of the same format as the 'plot' command.  If a marker is
     specified then the markers are drawn at the origin of the vectors
     (which are the grid points defined by X and Y).  When a marker is
     specified, the arrowhead is not drawn.  If the argument "filled" is
     given then the markers are filled.

     If the first argument HAX is an axes handle, then plot into this
     axes, rather than the current axes returned by 'gca'.

     The optional return value H is a graphics handle to a quiver
     object.  A quiver object regroups the components of the quiver plot
     (body, arrow, and marker), and allows them to be changed together.

     Example:

          [x, y] = meshgrid (1:2:20);
          h = quiver (x, y, sin (2*pi*x/10), sin (2*pi*y/10));
          set (h, "maxheadsize", 0.33);

     See also: quiver3, compass, feather, plot.

Additional help for built-in functions and operators is
available in the online version of the manual.  Use the command
'doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at https://www.octave.org and via the help@octave.org
mailing list.
octave:114> help quiver3
'quiver3' is a function from the file /usr/share/octave/7.3.0/m/plot/draw/quiver3.m

 -- quiver3 (X, Y, Z, U, V, W)
 -- quiver3 (Z, U, V, W)
 -- quiver3 (..., S)
 -- quiver3 (..., STYLE)
 -- quiver3 (..., "filled")
 -- quiver3 (HAX, ...)
 -- H = quiver3 (...)

     Plot a 3-D vector field with arrows.

     Plot the (U, V, W) components of a vector field at the grid points
     defined by (X, Y, Z).  If the grid is uniform then X, Y, and Z can
     be specified as vectors and 'meshgrid' is used to create the 3-D
     grid.

     If X and Y are not given they are assumed to be '(1:M, 1:N)' where
     '[M, N] = size (U)'.

     The optional input S is a scalar defining a scaling factor to use
     for the arrows of the field relative to the mesh spacing.  A value
     of 1.0 will result in the longest vector exactly filling one grid
     cube.  A value of 0 disables all scaling.  The default value is
     0.9.

     The style to use for the plot can be defined with a line style
     STYLE of the same format as the 'plot' command.  If a marker is
     specified then the markers are drawn at the origin of the vectors
     (which are the grid points defined by X, Y, Z).  When a marker is
     specified, the arrowhead is not drawn.  If the argument "filled" is
     given then the markers are filled.

     If the first argument HAX is an axes handle, then plot into this
     axes, rather than the current axes returned by 'gca'.

     The optional return value H is a graphics handle to a quiver
     object.  A quiver object regroups the components of the quiver plot
     (body, arrow, and marker), and allows them to be changed together.

          [x, y, z] = peaks (25);
          surf (x, y, z);
          hold on;
          [u, v, w] = surfnorm (x, y, z / 10);
          h = quiver3 (x, y, z, u, v, w);
          set (h, "maxheadsize", 0.33);

     See also: quiver, compass, feather, plot.

Additional help for built-in functions and operators is
available in the online version of the manual.  Use the command
'doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at https://www.octave.org and via the help@octave.org
mailing list.
octave:115> help feather
'feather' is a function from the file /usr/share/octave/7.3.0/m/plot/draw/feather.m

 -- feather (U, V)
 -- feather (Z)
 -- feather (..., STYLE)
 -- feather (HAX, ...)
 -- H = feather (...)

     Plot the '(U, V)' components of a vector field emanating from
     equidistant points on the x-axis.

     If a single complex argument Z is given, then 'U = real (Z)' and 'V
     = imag (Z)'.

     The style to use for the plot can be defined with a line style
     STYLE of the same format as the 'plot' command.

     If the first argument HAX is an axes handle, then plot into this
     axes, rather than the current axes returned by 'gca'.

     The optional return value H is a vector of graphics handles to the
     line objects representing the drawn vectors.

          phi = [0 : 15 : 360] * pi/180;
          feather (sin (phi), cos (phi));

     See also: plot, quiver, compass.

Additional help for built-in functions and operators is
available in the online version of the manual.  Use the command
'doc <topic>' to search the manual index.

Help and information about Octave is also available on the WWW
at https://www.octave.org and via the help@octave.org
mailing list.
octave:116> figure
octave:117> imshow([1 0; 0 1])
octave:118> imshow(1:255)
octave:119> imshow([1 .5; .5 1])
octave:120> whos
Variables visible from the current scope:

variables in scope: top scope

  Attr   Name        Size                     Bytes  Class
octave:124> whos
octave:125> x = [1 0; 0 1]
x =

   1   0
   0   1

octave:126> whose
error: 'whose' undefined near line 1, column 1
octave:127> whos
Variables visible from the current scope:

variables in scope: top scope

  Attr   Name        Size                     Bytes  Class
  ====   ====        ====                     =====  ===== 
         x           2x2                         32  double

Total is 4 elements using 32 bytes

octave:128> imshow(x)
octave:129> imshow(int(x))
error: 'int' undefined near line 1, column 8
octave:130> int
int16      int64      integral2  interp2    interpn    intmin     
int2str    int8       integral3  interp3    intersect  
int32      integral   interp1    interpft   intmax     
octave:130> imshow(int8(x))
error: imshow: invalid data type for image
error: called from
    imshow at line 199 column 9
octave:131> close all
octave:132> image = reshape(linspace(0, 1, 12), 2, 2, 3)
image =

ans(:,:,1) =

        0   0.1818
   0.0909   0.2727

ans(:,:,2) =

   0.3636   0.5455
   0.4545   0.6364

ans(:,:,3) =

   0.7273   0.9091
   0.8182   1.0000

octave:133> imshow(image)
octave:134> image(:, :, 3) = 0
image =

ans(:,:,1) =

        0   0.1818
   0.0909   0.2727

ans(:,:,2) =

   0.3636   0.5455
   0.4545   0.6364

ans(:,:,3) =

   0   0
   0   0

octave:135> imshow(image)
octave:136> image(:, :, 2) = 0
image =

ans(:,:,1) =

        0   0.1818
   0.0909   0.2727

ans(:,:,2) =

   0   0
   0   0

ans(:,:,3) =

   0   0
   0   0

octave:137> imshow(image)
octave:138> close all
octave:139> 
