# Correlation coefficient calculation error

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Josh on 23 Jun 2022
Commented: Mathieu NOE on 23 Jun 2022
As I try to find correlation coefficient for the respective variables i.e. 'td' & 'cumulat', in for loop, some error is coming in the process of execution. Please help.
clear;clc;close all
F = fieldnames(S);
for n = 1:numel(F)
F1 = fieldnames(S.(F{n}));
F11{n} = F1;
% allocate the variables
nn = cell(numel(F1),1);
PArea = cell(numel(F1),1);
t_max = cell(numel(F1),1);
for n1 = 1:numel(F1)
t = S.(F{n}).(F1{n1}).cc.t;
t_max{n1} = max(t);
nn{n1} = F1{n1};
output{n1} = cumtrapz(t);
NF = @(p,q) max(output{n1}(t<=q)) - min(output{n1}(t>=p));
PArea{n1} = NF(5, 6);
end
T_max{n} = t_max;
tt = cell2mat(T_max{1,n}(:,end));
td{n} = tt./max(tt);
cumulat{n} = PArea;
[R{n},P{n}] = corrcoef(td,cumulat); %correlation coeff. calculation
end
Error using corrcoef
Cannot compute p-values for complex inputs.
##### 1 CommentShowHide None
Jonas on 23 Jun 2022
can you please edit your question, format your code as code and press the compile button (green rectangle), this way we can see what is happening

Mathieu NOE on 23 Jun 2022
hello
seems to me the code could be made simpler, why the need to make all this cell acrobatics ?
clear;clc;close all
F = fieldnames(S);
for n = 1:numel(F)
F1 = fieldnames(S.(F{n}));
F11{n} = F1;
% allocate the variables
nn = cell(numel(F1),1);
for n1 = 1:numel(F1)
t = S.(F{n}).(F1{n1}).cc.t;
t_max(n1) = max(t);
nn{n1} = F1{n1};
output{n1} = cumtrapz(t);
NF = @(p,q) max(output{n1}(t<=q)) - min(output{n1}(t>=p));
PArea(n1) = NF(5, 6);
end
td = t_max./max(t_max);
cumulat = PArea;
[R{n},P{n}] = corrcoef(td,cumulat); %correlation coeff. calculation
end
Mathieu NOE on 23 Jun 2022
OK
all the best