-----------------------
Chapter: Variables
warning: marking 'document' as not implemented
octave:46> demo ("interp2", 1)
interp2 example 1:
 A=[13,-1,12;5,4,3;1,6,2];
 x=[0,1,4]; y=[10,11,12];
 xi=linspace(min(x),max(x),17);
 yi=linspace(min(y),max(y),26)';
 mesh(xi,yi,interp2(x,y,A,xi,yi,'linear'));
 [x,y] = meshgrid(x,y); 
 hold on; plot3(x(:),y(:),A(:),"b*"); hold off;

octave:47> 
octave:47>   
octave:47>   set (0, "defaultfigurevisible", "on")
octave:48> demo ("interp2", 1)
interp2 example 1:
 A=[13,-1,12;5,4,3;1,6,2];
 x=[0,1,4]; y=[10,11,12];
 xi=linspace(min(x),max(x),17);
 yi=linspace(min(y),max(y),26)';
 mesh(xi,yi,interp2(x,y,A,xi,yi,'linear'));
 [x,y] = meshgrid(x,y); 
 hold on; plot3(x(:),y(:),A(:),"b*"); hold off;

octave:49> close all
octave:50> demo ("interp2", 1)
interp2 example 1:
 A=[13,-1,12;5,4,3;1,6,2];
 x=[0,1,4]; y=[10,11,12];
 xi=linspace(min(x),max(x),17);
 yi=linspace(min(y),max(y),26)';
 mesh(xi,yi,interp2(x,y,A,xi,yi,'linear'));
 [x,y] = meshgrid(x,y); 
 hold on; plot3(x(:),y(:),A(:),"b*"); hold off;

octave:51> help axis
 -- Function File:  axis (LIMITS)
     Set axis limits for plots.

     The argument LIMITS should be a 2, 4, or 6 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, and the fifth and sixth specify the limits for the z axis.

     Without any arguments, `axis' turns autoscaling on.

     With one output argument, `x=axis' returns the current axes

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

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

     forces a square aspect ratio, and

          axis ("labely", "tic");

     turns tic marks on for all axes and tic mark labels on for the
     y-axis only.

     The following options control the aspect ratio of the axes.

    `"square"'
          Force a square aspect ratio.

    `"equal"'
          Force x distance to equal y-distance.

    `"normal"'
          Restore the balance.

     The following options control the way axis limits are interpreted.

    `"auto"'
          Set the specified axes to have nice limits around the data or
          all if no axes are specified.

    `"manual"'
          Fix the current axes limits.

    `"tight"'
          Fix axes to the limits of the data (not implemented).

     The option `"image"' is equivalent to `"tight"' and `"equal"'.

     The following options affect the appearance of tic marks.

    `"on"'
          Turn tic marks and labels on for all axes.

    `"off"'
          Turn tic marks off for all axes.

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

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

    `"nolabel"'
          Turn tic labels off for all axes.
     Note, if there are no tic marks for an axis, there can be no
     labels.

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

    `"ij"'
          Reverse y-axis, so lower values are nearer the top.

    `"xy"'
          Restore y-axis, so higher values are nearer the top.

     If an axes handle is passed as the first argument, then operate on
     this axes rather than the current axes.


octave:52> axis tight
octave:53> axis square
octave:54> axis ij
octave:55> close all
octave:56> help system
 -- Built-in Function:  system (STRING, RETURN_OUTPUT, TYPE)
     Execute a shell command specified by STRING.  The second argument
     is optional.  If TYPE is `"async"', the process is started in the
     background and the process id of the child process is returned
     immediately.  Otherwise, the process is started, and Octave waits
     until it exits.  If TYPE argument is omitted, a value of `"sync"'
     is assumed.

     If two input arguments are given (the actual value of
     RETURN_OUTPUT is irrelevant) and the subprocess is started
     synchronously, or if SYSTEM is called with one input argument and
     one or more output arguments, the output from the command is
     returned.  Otherwise, if the subprocess is executed synchronously,
     its output is sent to the standard output.  To send the output of
     a command executed with SYSTEM through the pager, use a command
     like

          disp (system (cmd, 1));

     or

          printf ("%s
          ", system (cmd, 1));

     The `system' function can return two values.  The first is the
     exit status of the command and the second is any output from the
     command that was written to the standard output stream.  For
     example,

          [status, output] = system ("echo foo; exit 2");

     will set the variable `output' to the string `foo', and the
     variable `status' to the integer `2'.


octave:57> exit
