attachment:dcor_dc.m of Geerligs_DistCor - MRC CBU Imaging Wiki
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## Attachment 'dcor_dc.m'

```   1 function [R] = dcor_dc(X,Y)
2 % [R] = dcor_dc(X,Y)
3 % Computes the double centered distance correlation between X and Y.
4 % Rows represent the examples, and columns the variables.
5
6 % Based on: http://www.mathworks.com/matlabcentral/fileexchange/49968-dcorr--x--y--
7 % and, the R package energy and papers by Szekely and Rizzo (2007; 2013 and 2014).
8
9 % Author: Linda Geerligs (lindageerligs@gmail.com), Date: 22-10-2015
10
11 a = pdist2(X, X);
12 b = pdist2(Y, Y);
13 n=size(X,1);
14
15 A = Dcenter(a);
16 B = Dcenter(b);
17
18 dcovXY = sum(sum(A.*B)) ./ (n.^2);
19 dvarX = sum(sum(A.*A)) ./ (n.^2);
20 dvarY = sum(sum(B.*B)) ./ (n.^2);
21
22 R=sqrt(dcovXY / sqrt(dvarX * dvarY));
23
24     function A=Dcenter(a)
25         A = a - bsxfun(@plus,mean(a),mean(a,2))+mean(a(:));
26     end
27
28 end
```

## Attached Files

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• [get | view] (2016-03-24 17:04:27, 41119.6 KB) [[attachment:Example_script.zip]]
• [get | view] (2016-03-24 16:49:34, 0.7 KB) [[attachment:dcor_dc.m]]
• [get | view] (2016-03-24 16:48:42, 1.1 KB) [[attachment:dcor_uc.m]]
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