CODEWITHSUNDEEP
matlab
Akshay
Akshay

Reputation: 2763

How to pre-allocate memory for 3d matrix? Matlab

So I have a .m file which gives me 128x14 every millisecond, I am calling it and creating an object of it "h". so now i get this warning when i hove over class1, class11, class2, class22, class3, class33, class4 and class44 its asking me to preallocate memory for them, so I tried searching for the option and got this. And this is a GUI application.

class1(:,:,samples_output) = zeros(128, 14, size(x));

I place the above code under "y" but when i run it i get this error

Subscripted assignment dimension mismatch.

  Error in training>start_training_Callback (line
  97)
  class1(:,:,samples_output) = zeros(128, 14,
  size(x));

  Error in gui_mainfcn (line 96)
          feval(varargin{:});

  Error in training (line 42)
      gui_mainfcn(gui_State, varargin{:});

  Error in
  @(hObject,eventdata)training('start_training_Callback',hObject,eventdata,guidata(hObject))


  Error while evaluating uicontrol Callback

This is the code

x = [0;1;0;-1];
  y = [1;0;-1;0];

  h = EmotivEEG;
  h.Run;

  for k = 1:samples_output

      location={};
      s=cell(1,4);
      for a = 1:4
          location{1} = sprintf('UP');
          location{2} = sprintf('RIGHT');
          location{3} = sprintf('DOWN');
          location{4} = sprintf('LEFT');
          n = location{a};
          s(a)=strread(sprintf(n),'%s','delimiter','');
      end

      set(handles.viewer_training,'YTick',[]);
      set(handles.viewer_training,'XTick',[]);
      scatter(x,y,'filled')
      text((x-.1),(y+.2),s,'color',[1,0,0]);
      hold on;  

      for s=1:size(x)
          samples_class_text = sprintf('Samples: %s \n Class: %s',num2str(k), num2str(s));
          set(handles.current_pos,'String',samples_class_text, 'FontSize', 15);
          set(handles.viewer_training,'YTick',[]);
          set(handles.viewer_training,'XTick',[]);
          scatter(x(s),y(s),400,'MarkerFaceColor',[0 0 0]);
          drawnow;
          if s == 1
              class1(:,:,s) = h.data;
              class11(:,:,s) = h.data;
              con1 = cat(3, class1(:,:,s), class11(:,:,s));
              assignin('base','class1',con1);
          elseif s == 2
              class2(:,:,s) = h.data;
              class22(:,:,s) = h.data;
              con2 = cat(3, class2(:,:,s), class22(:,:,s));
              assignin('base','class2',con2)
          elseif s == 3
              class3(:,:,s) = h.data;
              class33(:,:,s) = h.data;
              con3 = cat(3, class3(:,:,s), class33(:,:,s));
              assignin('base','class3',con3)
          elseif s == 4
              class4(:,:,s) = h.data;
              class44(:,:,s) = h.data;
              con4 = cat(3, class4(:,:,s), class44(:,:,s));
              assignin('base','class4',con4)
          end
          pause(1);
      end
      cla;
  end
  h.delete;

can anyone tell me how to preallocate the memory for those classes?

thanks in advance.

Upvotes: 0

Views: 129

Answers (1)

Daniel
Daniel

Reputation: 36710

class1(:,:,samples_output) indexes a 3d-matrix and returns a 2d-slice of it. To preallocate the full 3d matrix, use:

 class1 = zeros(128, 14, numel(x));

Upvotes: 2

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