Plotting data at a fast rate in app designer

Hey,

I have been trying to use app designer to plot data from a file. The file's data is originally collected with a 50 Hz sample rate. Is it at all possible to plot the data this fast in app designer. In the code I have now the frequency of the plotting can be changed by changing the period in the timer object creation. However, my computer struggles to plot the data even at a 0.5 second rate. Is there any way of plotting the data in a different way that allows for a faster frequency? So my code works, but it really isn't useful if I cannot plot at a higher frequency. There might be some parts in the code that are redundant such as the variable z, but you can ignore those.

All (hopefully) relevant parts of the code below.

properties (Access = private)
        aTimer % Timer object
        A
        ii
    end

    methods (Access = private)
    
        function aTimerFcn(app, ~, event)
            % get current time from timer's event data
            tnow = datetime(event.Data.time);
            app.ii = app.ii+1;
            A1 = app.A(app.ii,:);
            matrix = reshape(A1,[4,4]);
            y = rand();
            z = y+1;
            %cdata = rand(4,4);
            
            %data =rand(1,8);
           
            % Plot data and adjust XLim if current time is out of bounds
            xLL = app.UIAxes.XLim(1);
            xUL = app.UIAxes.XLim(2);
            if(tnow > xUL)
               xtra = seconds(15);
               app.UIAxes.XLim = [xLL+xtra tnow+xtra];
               app.UIAxes.XTick = linspace(xLL+xtra, tnow+xtra, 5);
            end
            plot(app.UIAxes, tnow, A1,'LineStyle',"-", "Marker","."); %, tnow, z, 'oy');
            heatmap(app.MatrixPanel, matrix, 'Colormap',parula,'CellLabelColor','none','ColorLimits',[410 420]);
            % Adjust YLim to show variations better
            yLL = 400; %max(y-5, 0);
            yUL = 430; %y + 5;
            app.UIAxes.YLim = [yLL yUL];
            %app.UIAxes.YTick = round(linspace(yLL, yUL, 5), 2, 'significant');
       end        
        
    end


    % Callbacks that handle component events
    methods (Access = private)

        % Code that executes after component creation
        function startupFcn(app)
            app.AAUIFigure.Name = 'AA Project V0.1 01APR21';
            % Plot invisible data point to initialize datetime ruler
            plot(app.UIAxes, datetime('now'), 50,'ob');
            cdata = rand(8,8);
            app.A = readmatrix('A.txt','FileType','text');
            heatmap(app.MatrixPanel, cdata);
           
            % Set x limits and ticks
            t = datetime('now') + seconds(1:60);
            app.ii = 0;
            xLL = t(1) - seconds(5);
            xUL = t(length(t));
            app.UIAxes.XLim = [xLL xUL];
            app.UIAxes.XAxis.TickLabelFormat = 'hh:mm:ss';
            app.UIAxes.XTick = linspace(xLL, xUL, 5);
            
            % Set y limits and ticks
            app.UIAxes.YLim = [0 50];
            app.UIAxes.YTick = round(linspace(0, 50, 5), 2, 'significant');
            grid(app.UIAxes,'on');
            hold(app.UIAxes,'on');
            
            % Create timer object
            app.aTimer = timer(...
            'ExecutionMode', 'fixedRate', ...      % Run timer repeatedly
            'Period',  1, ...                       % Period is 1 second
            'BusyMode', 'queue',...                % Queue timer callbacks when busy
            'TimerFcn', @app.aTimerFcn);   % Callback that runs every period
        end

Answer 1

[Mohammad Sami]

Similar to how you are storing UIAxes in the app properties you need to store the plot and the heatmap in the properies as well. Then you can update them in your timer function. That should speed up your code.

properties (Access = private)
        aTimer % Timer object
        A
        ii
        dataplot
        heatmapplot
    end
function startupFcn(app)
%....%
app.heatmapplot = heatmap(app.MatrixPanel, cdata,'Colormap',parula,'CellLabelColor','none','ColorLimits',[410 420]);
%....%
app.dataplot = plot(app.UIAxes, datetime('now'), 50,'LineStyle',"-", "Marker",".");
%....%
end

Then in timer function you can directly update the map and the plot.

function aTimerFcn(app, ~, event)
%....%
app.heatmapplot.ColorData = matrix;
%....%
app.dataplot.XData = tnow;
app.dataplot.YData = A1;
end