How to obtain mean of columns in multiple cells?

I have a cell (say "a") and it has 5X1 dimension , Class: Cell. (Shown in picture below)

Each cell contains different cells, having size 3439x72 Single.

Now, I want to obtain the mean values of

a{1,1}(1,:) , a{2,1}(1,:) , a{3,1}(1,:) , a{4,1}(1,:) , a{5,1}(1,:),...

a{1,1}(2,:) , a{2,1}(2,:) , a{3,1}(2,:) , a{4,1}(2,:) , a{5,1}(2,:),...

a{1,1}(3,:) , a{2,1}(3,:) , a{3,1}(3,:) , a{4,1}(3,:) , a{5,1}(3,:),...

...

...

...

a{1,1}(3439,:) , a{2,1}(3439,:) , a{3,1}(3439,:) , a{4,1}(3439,:) , a{5,1}(3439,:)

The final output will be one cell with size 1x1 containing mean values of matrix "a" and having dimension 3439x72 Single.

Can anyone please help. Any help will be greatly appriciated.

The picture below shows the example of matrix "a".

Answer 1

[Chunru]

% Generate data
for i=1:5
    a{i} = randn(3439, 72);
end

% find means
s = zeros(size(a{1}));
for i=1:5
    s = s + a{i};
end
s = s/5;
m{1} = s  % if cell output is needed

m = 1×1 cell array
    {3439×72 double}

% Another way
% convert the cell array to n-d arraym
b = cell2mat(a);
b = reshape(b, 3439, 72, []);
bmean = mean(b, 3, 'omitnan')

bmean = 3439×72

-0.1072 0.7186 -1.2518 0.6538 0.0450 0.2487 -0.0131 -0.5979 0.0913 0.2459 0.2499 -0.4384 0.2268 1.2775 0.4260 0.3953 1.1213 0.4292 -0.5834 -0.0036 -0.5446 -0.2942 -0.3175 -0.0058 0.3379 0.0833 -0.1570 -0.4981 0.6502 -0.3571 0.3296 -0.3576 -0.0878 0.7029 -0.3468 -0.3598 0.3431 0.2771 -0.3125 0.4491 0.2682 0.3570 0.3437 1.4581 -0.1591 0.2845 -0.0704 0.4437 0.1149 -0.5652 0.3740 0.5756 0.3369 0.2193 -0.0896 0.7258 0.1833 -0.2490 0.6524 0.3205 0.7501 -0.7461 0.0481 -0.6806 -0.0029 -0.4085 0.1619 0.3956 0.1897 -0.9844 0.3036 0.5573 0.1616 -0.5567 -0.2975 0.3156 -0.4230 -0.3315 0.2060 0.4804 -0.2614 0.3183 -0.3542 1.0261 0.2275 0.3702 0.2705 -0.1034 0.9476 0.4038 0.5143 -0.6436 0.4221 0.0232 0.6096 0.6368 -0.0515 0.6973 -0.6362 -0.5205 0.0560 -0.0415 -0.7558 0.6641 0.6799 -0.3440 0.0877 0.3927 -0.0997 -0.9058 0.4118 -0.0052 -0.1239 0.7165 -0.0513 -0.4080 0.0001 -0.0915 -0.3898 0.3817 -0.2457 -0.3139 -0.0633 -0.2184 0.3175 0.6855 0.1546 0.1740 0.3062 0.2652 0.0356 0.4685 -0.6416 0.0628 -0.0215 0.1770 -0.1564 -0.1714 0.5383 -0.0258 1.0216 -0.2419 0.0912 -0.6164 0.7431 -0.5076 0.2734 0.4250 0.2200 0.7192 0.4551 -0.2876 0.3299 -0.6889 -0.2404 -0.8372 0.0219 -0.0181 0.1463 -0.5245 0.2721 0.1144 0.1633 -0.3012 0.2346 0.4896 0.0539 -0.4367 -0.4442 -0.1432 0.3200 -0.3041 0.4268 -0.1290 -0.3429 0.5477 -0.0069 -0.1900 -0.3022 0.6622 -0.0253 0.3395 0.0301 -0.2680 -0.0379 0.1428 0.3302 0.0596 0.5808 -0.0830 -0.2721 0.6924 0.0888 0.8348 0.1913 0.0173 -0.1094 0.3777 0.2724 -0.4384 -0.0410 0.3503 0.5023 0.2206 -0.5890 0.0367 -0.3338 0.9258 -0.4508 -0.2004 0.0719 1.0938 0.8232 -0.2318 0.1890 0.1043 -0.4000 0.2134 -0.2826 -0.1097 0.6548 0.4961 0.3926 -0.5436 -0.1727 -0.5459 0.1039 0.0243 0.1120 -0.1421 -0.3257 0.8620 -0.3420 0.0868 -0.4102 -0.3604 -0.1350 0.4695 0.0834 0.3250 -0.3574 -0.1595 0.1768 -0.0326 -0.2493 0.1360 0.2644 0.3307 -0.0123 0.0974 0.2792 -0.6300 0.5049 -0.0481 -0.0354 -0.8216 -0.1767 -0.3365 0.1326 0.4728 -0.3519 -0.2839 0.4667 0.1003 0.1995 -0.4195 -0.4603 1.2199 -0.0732 -0.5929 -0.5021 -0.7128 -0.6214 0.3192 0.1684 -0.2102 0.4546 0.3216 0.6002 0.0061 0.2754 0.0905 -0.4532 -0.4504 0.4331 0.2006 -0.0750 -0.7206 -0.8921 0.5873 -0.0347 -0.1797 -1.4079 -0.2568 0.0494 -0.0938 0.9003 0.1116 -0.6840 -0.5167

whos

  Name           Size                Bytes  Class     Attributes

  a              1x5               9904840  cell                
  b           3439x72x5            9904320  double              
  bmean       3439x72              1980864  double              
  cmdout         1x33                   66  char                
  i              1x1                     8  double              
  m              1x1               1980968  cell                
  s           3439x72              1980864  double              

[MP]

Thank you so much very great help.

[MP]

That appears to create some trouble when NaN values are present. Could you please help.

I want NaNMean.

[Chunru]

see the update for handling nan.

[MP]

Hi Chunru. Thank you very much for helping.

This example works fine here and other cases. But why does it show wrong output for my actual data.

Here is my actual data attached. I hope you will be able to understand it.

here "bmean.mat" does not show the correct output of mean values in matrix "a.mat".

Here is my code:

Am I doing something wrong?

Could you please help.

FODU5 = cell2mat(FODU4);

FODU5 = reshape(FODU5, 3439, 72, []); 
FODU6 = mean(FODU5, 3, 'omitnan'); 

[Chunru]

%load(websave("bmean.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1150810/bmean.mat"))
%load(websave("b.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1150815/b.mat"))
load(websave("a.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1150820/a.mat"))
FODU4   % This is a 5x1 cell array instead of 1x5 array

FODU4 = 5×1 cell array
    {3439×72 single}
    {3439×72 single}
    {3439×72 single}
    {3439×72 single}
    {3439×72 single}

FODU5 = cell2mat(FODU4');           % tranpose the cell array so that cell2mat works
FODU5 = reshape(FODU5, 3439, 72, []); 
FODU6 = mean(FODU5, 3, 'omitnan'); 
whos

  Name           Size                Bytes  Class     Attributes

  FODU4          5x1               4952680  cell                
  FODU5       3439x72x5            4952160  single              
  FODU6       3439x72               990432  single              
  cmdout         1x33                   66  char                

[MP]

Yes, transpose did work!!

Thank you so very much.