How can to compute the following case?

Question

M 2023-7-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1997378-how-can-to-compute-the-following-case

移动：Torsten 2023-7-18

采纳的回答： Torsten

D.mat

在 MATLAB Online 中打开

If there is a cell D and its size 6*9 and this cell contains matrices. (Attached)

in this line: svd(D{1,1}.'*D{1,2});

how can I change the indices of D to do the multiplication of all combinations of D but without repeat the similar combinations such as:

D{1,1}.'*D{1,2} and D{1,2}.'*D{1,1}

and exclude the similar indicies such as

D{1,1}.'*D{1,1} and so on ...

Then store all the results in "distance"

                [U,S,V]  = svd(D{1,1}.'*D{1,2});
                distance = sqrt(sum(arrayfun(@(i)acos(S(i,i))^2,1:4)))
          

2 个评论
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Chunru 2023-7-18

Can you give an example of your data D?

M 2023-7-18

@Chunru I attached the file

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Answer 1

Torsten 2023-7-18

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1997378-how-can-to-compute-the-following-case#answer_1275203

移动：Torsten 2023-7-18

在 MATLAB Online 中打开

D.mat

  D = load("D.mat");
  D = D.D;
  n = size(D,1);
  m = size(D,2);
  distance = zeros(n,m,n,m);
  for i=1:n
    for j=1:m
        for i1=1:n
            for j1=1:m
                [~,S,~]  = svd(D{i,j}.'*D{i1,j1});
                distance(i,j,i1,j1) = sqrt(sum(arrayfun(@(k)acos(S(k,k))^2,1:size(S,1))));
            end
        end
    end
  end
 [M,I] = max(distance,[],'All')
M = 1.5695
I = 2592
 [i,j,i1,j1] = ind2sub([n,m,n,m],I)
i = 6
j = 9
i1 = 6
j1 = 8
 distance(6,9,6,8)
ans = 1.5695
 distance(6,8,6,9)
ans = 1.5695

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Answer 2

Chunru 2023-7-18

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1997378-how-can-to-compute-the-following-case#answer_1274898

在 MATLAB Online 中打开

load(websave("D.mat", "https://www.mathworks.com/matlabcentral/answers/uploaded_files/1436693/D.mat"));
for i=1:size(D, 1)
    for j=1:size(D, 2)
        for i1=1:size(D, 1)
            for j1=1:size(D, 2)
                S{i,j,i1,j1} = D{i,j} - D{i1,j1};
            end
        end
    end
end
whos
  Name        Size                Bytes  Class     Attributes

  D           6x9                 15984  cell                
  S           6x9x6x9            863136  cell                
  cmdout      1x33                   66  char                
  i           1x1                     8  double              
  i1          1x1                     8  double              
  j           1x1                     8  double              
  j1          1x1                     8  double              
S{1, 2, 3, 4}       % for example: D{1,2}-D{3,4}
ans = 6×4
   -0.0068    0.1359    0.2272    0.2585
   -0.5386    0.0657    0.4552    0.5899
    0.2370    0.1540    0.0995    0.0803
    0.1061    0.0122   -0.0485   -0.0696
    0.0210   -0.0793   -0.1435   -0.1655
   -0.0087   -0.1109   -0.1761   -0.1985