Compute correlations in 3D arrays

Question

julian gaviria 2023-11-6

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2043817-compute-correlations-in-3d-arrays

评论： julian gaviria 2023-11-7

%Random matrices
A=randi(100,374,374);
A_ = eye(size(A,[1 2]));
A(ones(size(A))&A_)=NaN;
B=randi(100,374,374);
B_ = eye(size(B,[1 2]));
B(ones(size(B))&B_)=NaN;

The following code computes correlation coeficient and p value from matrices A, B:

nn=374;
temp= ~eye (nn);
ii_all_conn = find(temp>0);
ii_uptri_conn = find(triu(temp,1)> 0);
ii_lotri_conn = find(tril(temp,-1)> 0);
%Corr plots up entries
figure, plot(A(ii_uptri_conn), B(ii_uptri_conn),'o');
[r,p]= corr(A(ii_uptri_conn), B(ii_uptri_conn));
title(['Upper connections - r = ' num2str(r) ' (p ' num2str(p) ')']);
%Corr plots low entries
figure, plot(A(ii_lotri_conn), B(ii_lotri_conn),'o');
[r,p]= corr(A(ii_lotri_conn), B(ii_lotri_conn));
title(['Lower connections - r = ' num2str(r) ' (p ' num2str(p) ')']);

Can I compute the same correlation and p-value in multidimensional arrays? E.g.

A_3D=randi(100,374,374,10);
B_3D=randi(100,374,374,10);

In the output, the first r and p values would correpond to the Pearson coeficient of A(:,:,1), B(:,:,1). and the tenth r and p values correpond to the Pearson coeficient of A(:,:,10), B(:,:,10)

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Answer 1

Dyuman Joshi 2023-11-7

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/2043817-compute-correlations-in-3d-arrays#answer_1347872

在 MATLAB Online 中打开

Run a for loop through the 3rd dimension -

A_3D = randi(100,374,374,10);
B_3D = randi(100,374,374,10);
s = size(A_3D,3);
[ru, pu, rl, pl] = deal(zeros(s,1));
for k = 1:s
    [ru(k), pu(k), rl(k), pl(k)] = correlation(A_3D(:,:,k), B_3D(:,:,k));    
end
%Upper triangle values
[ru pu]
ans = 10×2
    0.0029    0.4429
    0.0032    0.3950
    0.0069    0.0684
   -0.0013    0.7218
   -0.0056    0.1426
   -0.0027    0.4775
   -0.0026    0.4976
   -0.0055    0.1459
   -0.0012    0.7442
    0.0031    0.4171
%Lower triangle values
[rl pl]
ans = 10×2
    0.0007    0.8508
   -0.0015    0.6969
   -0.0113    0.0028
    0.0065    0.0878
    0.0001    0.9798
    0.0064    0.0892
   -0.0038    0.3129
   -0.0029    0.4408
   -0.0012    0.7495
    0.0043    0.2520

function [Ru, Pu, Rl, Pl] = correlation(A, B)
A = modify(A);
B = modify(B);
temp= ~eye(size(A,[1 2]));
%% Logical indexing is faster than find()
ii_uptri_conn = triu(temp,1)> 0;
ii_lotri_conn = tril(temp,-1)> 0;
[Ru,Pu] = corr(A(ii_uptri_conn), B(ii_uptri_conn));
[Rl,Pl] = corr(A(ii_lotri_conn), B(ii_lotri_conn));
end
function in = modify(in)
temp = eye(size(in,[1 2]));
in(ones(size(in))&temp) = NaN;
end