How to code a slider in Octave to have interactive plot?

Question

my target is to have a plot that shows Stochastic oscillator on forex market, and in order to validate which parameter is the best one to setup it, I would use a slider to modify it and show updated result on plot.

I have my historical data, for a defined pair (let say AUDUSD) and after loading it, I calculate Stocastic oscillator:

function [stoch, fk, dk] = stochastic(n, k, d)
    X=csvread("AUDUSD_2017.csv");
    C=X(2:length(X),5);
    L=X(2:length(X),4);
    H=X(2:length(X),3);
    O=X(2:length(X),2);
    for m=n:length(C)-n
        stoch(m)=((C(m)-min(L(m-n+1:m)))/(max(H(m-n+1:m))-min(L(m-n+1:m))))*100;

    endfor

for m=n:length(C)-n

    fk(m)=mean(stoch(m-d:m));

 endfor
for m=n:length(C)-n

    dk(m)=mean(fk(m-d:m));
endfor


endfunction

This is a picture of what I have when I plot stoch, fk and dk:

I would add 3 sliders to the figure in order to change, in a range, parameters as input, so i.e. to have a slider that changes first parameter "n" between 3 and 50, "k" between 2 and 20, and "d" between 2 and 20.

I would use UI package in octave, can someone address me to have a plot updated when I use sliders?

Francesco

Answer 1

Andy pointed out in the comments that the example I linked to doesn't work on octave out of the box; this is because Octave doesn't like nested functions for certain things for the time being, so I've reproduced an 'octave version' below.

%%%%%% In file myplot.m %%%%%
function myplot

  %% Create initial figure and spiral plot
  figure;  axes ('position', [0.1, 0.3, 0.8, 0.6]);
  global t;   t = linspace (0, 8*pi, 100);
  x = t .* cos(t);  y = t .* sin(t);
  plot (x, y);  axis ([-100, 100, -100, 100]);

  %% Add ui 'slider' element      
  hslider = uicontrol (                    ...
         'style', 'slider',                ...
         'Units', 'normalized',            ...
         'position', [0.1, 0.1, 0.8, 0.1], ...
         'min', 1,                         ...
         'max', 50,                        ...
         'value', 10,                      ...
         'callback', {@plotstuff}          ...
       );
end

%% Callback function called by slider event
%% Also in file myplot.m (i.e. a subfunction)
function plotstuff (h, event)
  global t;
  n = get (h, 'value');
  x = n * t .* cos(t);  y = n * t .* sin(t);
  plot (x, y);  axis ([-100, 100, -100, 100]);
end

Answer 2

Have a look at this demo which will give you an window like that which should answer all your questions:

The relevant parts for your specific questions are:

h.noise_slider = uicontrol ("style", "slider",
                            "units", "normalized",
                            "string", "slider",
                            "callback", @update_plot,
                            "value", 0.4,
                            "position", [0.05 0.25 0.35 0.06]);
....
 noise = get (h.noise_slider, "value");

Be sure to use the Qt toolkit!