working with tall cell array

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ghattas bisharat 2023-9-6

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https://ww2.mathworks.cn/matlabcentral/answers/2017361-working-with-tall-cell-array

回答： Seth Furman 2023-9-13

i have convert table data (three field contains integers or string and the forth field contains 3D matrix) to tall array, I noticed that the forth field is actually tall cell array, and i was wondering what is the right syntax that can be used in order to extract the data and perorm zscore calculations for all the rows of this field?

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Shubham 2023-9-6

You can try using the function "gather". Read more here:Collect tall array into memory after executing queued operations - MATLAB gather (mathworks.com)

ghattas bisharat 2023-9-6

Thanks, i was acually hoping for something that doesn't require a variable assignment that takes up memory(due to the large data sets that i'm working with) because this keeps causing MATLAB to become really slow or even stop working.

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Answer 1

Seth Furman 2023-9-13

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https://ww2.mathworks.cn/matlabcentral/answers/2017361-working-with-tall-cell-array#answer_1309421

在 MATLAB Online 中打开

Example for regular cell arrays

C = mat2cell(magic(10),repmat(1,10,1))
C = 10×1 cell array
    {[   92 99 1 8 15 67 74 51 58 40]}
    {[  98 80 7 14 16 73 55 57 64 41]}
    {[  4 81 88 20 22 54 56 63 70 47]}
    {[  85 87 19 21 3 60 62 69 71 28]}
    {[   86 93 25 2 9 61 68 75 52 34]}
    {[ 17 24 76 83 90 42 49 26 33 65]}
    {[  23 5 82 89 91 48 30 32 39 66]}
    {[  79 6 13 95 97 29 31 38 45 72]}
    {[ 10 12 94 96 78 35 37 44 46 53]}
    {[11 18 100 77 84 36 43 50 27 59]}
cellfun(@(x)zscore(x,1),C,UniformOutput=false)
ans = 10×1 cell array
    {[  1.2757 1.4909 -1.5216 -1.3065 -1.0913 0.5072 0.7224 0.0154 0.2306 -0.3228]}
    {[  1.6406 1.0189 -1.5025 -1.2607 -1.1916 0.7771 0.1554 0.2245 0.4663 -0.3281]}
    {[  -1.7789 1.1668 1.4346 -1.1668 -1.0903 0.1339 0.2104 0.4782 0.7460 -0.1339]}
    {[  1.2098 1.2799 -1.1046 -1.0345 -1.6656 0.3331 0.4033 0.6487 0.7189 -0.7890]}
    {[  1.1779 1.4102 -0.8461 -1.6093 -1.3770 0.3484 0.5807 0.8129 0.0498 -0.5475]}
    {[-1.3365 -1.0573 1.0174 1.2966 1.5759 -0.3391 -0.0598 -0.9775 -0.6982 0.5785]}
    {[-0.9673 -1.6004 1.1080 1.3542 1.4246 -0.0879 -0.7211 -0.6507 -0.4045 0.5452]}
    {[0.9089 -1.4191 -1.1959 1.4191 1.4829 -0.6857 -0.6219 -0.3986 -0.1754 0.6857]}
    {[-1.4030 -1.3337 1.5070 1.5762 0.9527 -0.5370 -0.4677 -0.2252 -0.1559 0.0866]}
    {[-1.4159 -1.1650 1.7744 0.9499 1.2008 -0.5198 -0.2688 -0.0179 -0.8424 0.3047]}

Example for tall cell arrays

parpool("Threads");
Starting parallel pool (parpool) using the 'Threads' profile ...
Connected to parallel pool with 2 workers.
tC = tall(C)
tC =

  10×1 tall cell array

    {[  92 99 1 8 15 67 74 51 58 40]}
    {[ 98 80 7 14 16 73 55 57 64 41]}
    {[ 4 81 88 20 22 54 56 63 70 47]}
    {[ 85 87 19 21 3 60 62 69 71 28]}
    {[  86 93 25 2 9 61 68 75 52 34]}
    {[17 24 76 83 90 42 49 26 33 65]}
    {[ 23 5 82 89 91 48 30 32 39 66]}
    {[ 79 6 13 95 97 29 31 38 45 72]}
    :  :  : :  :  :  :  :  :  :   :
    :  :  : :  :  :  :  :  :  :   :
cellfun(@(x)zscore(x,1),C,UniformOutput=false)
ans = 10×1 cell array
    {[  1.2757 1.4909 -1.5216 -1.3065 -1.0913 0.5072 0.7224 0.0154 0.2306 -0.3228]}
    {[  1.6406 1.0189 -1.5025 -1.2607 -1.1916 0.7771 0.1554 0.2245 0.4663 -0.3281]}
    {[  -1.7789 1.1668 1.4346 -1.1668 -1.0903 0.1339 0.2104 0.4782 0.7460 -0.1339]}
    {[  1.2098 1.2799 -1.1046 -1.0345 -1.6656 0.3331 0.4033 0.6487 0.7189 -0.7890]}
    {[  1.1779 1.4102 -0.8461 -1.6093 -1.3770 0.3484 0.5807 0.8129 0.0498 -0.5475]}
    {[-1.3365 -1.0573 1.0174 1.2966 1.5759 -0.3391 -0.0598 -0.9775 -0.6982 0.5785]}
    {[-0.9673 -1.6004 1.1080 1.3542 1.4246 -0.0879 -0.7211 -0.6507 -0.4045 0.5452]}
    {[0.9089 -1.4191 -1.1959 1.4191 1.4829 -0.6857 -0.6219 -0.3986 -0.1754 0.6857]}
    {[-1.4030 -1.3337 1.5070 1.5762 0.9527 -0.5370 -0.4677 -0.2252 -0.1559 0.0866]}
    {[-1.4159 -1.1650 1.7744 0.9499 1.2008 -0.5198 -0.2688 -0.0179 -0.8424 0.3047]}