how to split an 8x8 2D array

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Freja
Freja 2023-8-10
评论： C B 2023-8-10
how would I split an 8x8 2D array into four 4x4 arrays so that I can take the mean of each 4x4 array using the mean function?

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C B
C B 2023-8-10
编辑：C B 2023-8-10
Ran in:
Is this what you are looking for?
% Sample 8x8 array
A = reshape(1:64, [8,8])
A = 8×8
1 9 17 25 33 41 49 57 2 10 18 26 34 42 50 58 3 11 19 27 35 43 51 59 4 12 20 28 36 44 52 60 5 13 21 29 37 45 53 61 6 14 22 30 38 46 54 62 7 15 23 31 39 47 55 63 8 16 24 32 40 48 56 64
% Splitting into 4x4 arrays
A1 = A(1:4, 1:4)
A1 = 4×4
1 9 17 25 2 10 18 26 3 11 19 27 4 12 20 28
A2 = A(1:4, 5:8)
A2 = 4×4
33 41 49 57 34 42 50 58 35 43 51 59 36 44 52 60
A3 = A(5:8, 1:4)
A3 = 4×4
5 13 21 29 6 14 22 30 7 15 23 31 8 16 24 32
A4 = A(5:8, 5:8)
A4 = 4×4
37 45 53 61 38 46 54 62 39 47 55 63 40 48 56 64
% Computing the mean for each 4x4 array
mean_A1 = mean(A1(:));
mean_A2 = mean(A2(:));
mean_A3 = mean(A3(:));
mean_A4 = mean(A4(:));
% Displaying the results
fprintf('Mean of A1: %f\n', mean_A1);
Mean of A1: 14.500000
fprintf('Mean of A2: %f\n', mean_A2);
Mean of A2: 46.500000
fprintf('Mean of A3: %f\n', mean_A3);
Mean of A3: 18.500000
fprintf('Mean of A4: %f\n', mean_A4);
Mean of A4: 50.500000
  2 个评论
Freja
Freja 2023-8-10
yes thank you! also would there be a way to create a loop to index that and do each calculation for you?
C B
C B 2023-8-10
Ran in:
Yes we can use loop for splitting and Mean calculation
A = reshape(1:64, [8,8]);
mean_values = zeros(1, 4);
% Loop to extract 4x4 matrices and compute mean
for row = 1:2
for col = 1:2
r = (row-1)*4 + 1 : row*4;
c = (col-1)*4 + 1 : col*4;
submatrix = A(r, c);
idx = (row-1)*2 + col;
mean_values(idx) = mean(submatrix(:));
end
end
for i = 1:4
fprintf('Mean of A%d: %f\n', i, mean_values(i));
end
Mean of A1: 14.500000 Mean of A2: 46.500000 Mean of A3: 18.500000 Mean of A4: 50.500000

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