Identifying and plotting unique combinations of data

Question

fadzhi 2021-2-4

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/736332-identifying-and-plotting-unique-combinations-of-data

评论： fadzhi 2021-2-8

采纳的回答： lk

AA7075.txt

Dear all,

I am not really an expert at Matlab and needed help in the following function and will really appreciate it.

I have written a function to identify and plot the data belonging to a unique combination of first column= temperature and second clumn= strain rate (Total 16 combinations, please see attached file).......I am using 'unique' command to identify each value in the first column. However, i am not getting the desired plot of 16 curves. I think same temperature values in first column is problematic. Therefore, it is not able to identify it properly. The function is below:

kf1 = GetKf('AA7075');

[nT, nE] = size(kf1);

% plot all flow curves

figure; hold on;

for i=1:nT

for j=1:nE

if i==1

plot(kf0(i,j).e, kf0(i,j).s, 'r-');

elseif i==2

plot(kf0(i,j).e, kf0(i,j).s, '-');

else

plot(kf0(i,j).e, kf0(i,j).s, 'k-');

end

txt1=[num2str(kf0(i,j).T) ' C, ' num2str(kf0(i,j).e_dot) ' /s'];

text(kf0(i,j).e(end)+0.1, kf0(i,j).s(end), txt1);

end

function kf = GetKf(fname)

cname = ['load' fname '.txt;'];

eval(cname);

cname = ['kf_all=' fname ';'];

eval(cname);

Ts = unique(kf_all(:,1));

for i=1:length(Ts)

Tindx = find(kf_all(:,1)==Ts(i));

kf_T = kf_all(Tindx,2:4);

e_dots = unique(kf_T(:,1));

for j = 1:length(e_dots)

Eindx = find(kf_T(:,1)==e_dots(j));

kf(i,j).T=Ts(i);

kf(i,j).e_dot=e_dots(j);

kf(i,j).e = kf_T(Eindx,2);

kf(i,j).s = kf_T(Eindx,3);

end;

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Answer 1

lk 2021-2-5

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/736332-identifying-and-plotting-unique-combinations-of-data#answer_616017

Hi fadzhi,

If I understand correctly, you are trying to find all unique combinations of column1 and column2 data. Here is an example of how you could do it, and get the data for columns 3 and 4 for each unique combination. Hope this helps.

tempStrainRate = kf_all(:, 1:2);

[Ts, ~, ib] = unique(tempStrainRate, 'rows');

% the indices code comes from here: https://www.mathworks.com/matlabcentral/answers/331309-matlab-find-unique-column-combinations-in-matrix-and-respective-index

indices = accumarray(ib, find(ib), [], @(rows){rows});

% for i, where i is your combination index from 1 to size(Ts, 1) %this gives you number of rows

% to get all data for a temp/strain rate combination,

kf_all(indices{i}, 1:4);

% to get just columns 3 and 4

kf_all(indices{i}, 3:4);

% to get individual columns

kf_all(indices{i}, 3);

kf_all(indices{i}, 4);

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fadzhi 2021-2-8

AA7075.txt

There is an small issue. Instead of getting all 16 x 2 unique combination, i am getting only 8 x 2. This is becuase a combination repeats multiple times. I have attached the data. Perhaps you have a suggestion?

kf_all = load('AA7075.txt');

tempStrainRate = kf_all(:, 1:2);

[Ts, ~, ib] = unique(tempStrainRate, 'rows');

% % % the indices code comes from here: https://www.mathworks.com/matlabcentral/answers/331309-matlab-find-unique-column-combinations-in-matrix-and-respective-index

indices = accumarray(ib, find(ib), [], @(rows){rows});

fadzhi 2021-2-8