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Assign values of .mat files into matrix

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Tessa Kol
Tessa Kol on 19 Oct 2020
Edited: Tessa Kol on 21 Oct 2020
Dear all,
I have multiple .mat files (see attachment). I want to organize the MFR_mod variables within the those .mat files into one matrix. I feel like there is a smarter way then what I tried below. This will take me forever, since MFR_mod goes from 1 until 81.
for ii = 1:20
load(['silomodresults',num2str(ii),'.mat'])
end
MFR_tot = [MFR_mod1; MFR_mod2; MFR_mod3; MFR_mod4; MFR_mod5; MFR_mod6; MFR_mod7; MFR_mod8; MFR_mod9; MFR_mod10; MFR_mod11; MFR_mod12; MFR_mod13; MFR_mod14; MFR_mod15; MFR_mod16; MFR_mod17; MFR_mod18; MFR_mod19; MFR_mod20];

Accepted Answer

Stephen Cobeldick
Stephen Cobeldick on 19 Oct 2020
Edited: Stephen Cobeldick on 19 Oct 2020
D = 'path to the folder where the files are saved';
S = dir(fullfile(D,'silomodresults*.mat'));
C = {};
for k = 1:numel(S)
F = fullfile(D,S(k).name);
T = load(F,'-regexp','^MFR_mod\d+$');
N = fieldnames(T);
V = str2double(regexp(N,'\d+','once','match'));
C(V) = struct2cell(T); %#ok<SAGROW>
end
M = vertcat(C{:}); % optional
Giving:
>> size(M)
ans =
81 1
>> plot(M)
  9 Comments
Tessa Kol
Tessa Kol on 21 Oct 2020
Thank you for the tip!
The indices are based on poor folder structure management from my side.

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More Answers (2)

Ameer Hamza
Ameer Hamza on 19 Oct 2020
Edited: Ameer Hamza on 19 Oct 2020
One of the major problem is naming the variables like this x1, x2, ...: https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval. You can try something like this
MFR_tot = zeros(1, 20);
for ii = 1:20
data = load(['silomodresults',num2str(ii),'.mat']);
MFR_tot(ii) = data.(sprintf('MFR_mod%d', ii))
end
  1 Comment
Tessa Kol
Tessa Kol on 19 Oct 2020
I came across the issue with eval many times in different posts. You solution didn't work unfortunatly, because the .mat files have unorganized MFR_mod. Maybe if I start from the beginning there is a better solution to this.
So first I have created 20 .mat files. Each .mat file is about 1.5 GB. So it is not possible to send it in this post.
For each .mat file I run the same code manually. The below code is an example of running the code for only the silomoddata20.mat file.
%% Loading the Data
load([pwd,'\silomoddata20.mat'])
%% Parameters
% Number of simulation runs
N_run = numel(runData_struc);
TimeStepstable = [3.04, 6.5];
TimeStepsettle = [1.56];
%% Mass flow Rate
% Pre-allocate one cell for each loop variable
particlesInSilo = cell(max(cellfun(@numel,runData_struc)), N_run);
siloMass = particlesInSilo;
time = particlesInSilo;
k =1;
for i = 1:N_run
for j = 1:numel(runData_struc{i})
%Count the number of particles in the silo (silo outlet is located at z = 0.3 m)
particlesInSilo{j,i} = find(expData_struc{1,i}{1,j}(:,3)>=0.3);
% Multiply the number of particles with the volume of the particle
siloMass{j,i} = sum(expData_struc{1,i}{1,j}(cell2mat(particlesInSilo(j,i)),6));
% Corresponding time step
time{j,i} = runData_struc{1,i}{1,j}(:,2);
k = k + 1;
end
end
% Index the time step values closest to the desired time step where the mass flow is stable
for i = 1:N_run
for t = 1:numel(TimeStepstable)
[~, idxtime(t,i)] = min(abs(cell2mat(time(:,i))-TimeStepstable(t)));
end
end
% Calculate the mass flow rate (MFR) for the stable region
for i = 1:N_run
siloMass_stable{i} = cell2mat(siloMass(idxtime(1,i):idxtime(2,i),i));
time_stable{i} = cell2mat(time(idxtime(1,i):idxtime(2,i),i));
opts = fitoptions('Method', 'LinearLeastSquares', 'Robust', 'off');
[MFR_fit{i}, GoodnessOfFit] = fit(time_stable{i}(:,1),siloMass_stable{i}(:,1),'poly1',opts);
MFR_mod(i) = abs(MFR_fit{i}.p1);
end
%% save results
save silomodresults20.mat MFR_mod rho_bmod
I run the above code manually for every silomoddata*.mat file. Because I didn't know how to put this in a for loop.
If the whole code is in for loop I hope to get a 1x81 matrix of MFR_mod. The problem with that is the order.
silomoddata1.mat contains simulationrun 1
silomoddata2.mat contains simulationrun 2
silomoddata3.mat contains simulationrun 3
silomoddata4.mat contains simulationrun 4
silomoddata5.mat contains simulationrun 5, simulationrun 11, simulationrun 20, simulationrun 38 and simulationrun 81
silomoddata6.mat contains simulationrun 12, simulationrun 15, simulationrun 31, simulationrun 55 and simulationrun 65
silomoddata20.mat contains simulationrun 77, simulationrun 78, simulationrun 79, simulationrun 80
... etc.
When I calculated the MFR_mod of every silomoddata.mat file I can't just simply combine them into a matrix. The orde isn't right. That was what I am trying to achieve here, a matrix of MFR_mod in the correct order of 1 until 81.

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Mathieu NOE
Mathieu NOE on 19 Oct 2020
hello
seems all your mat file contains the same size of data
so the modification of you r code is fairly simple - if I understand what you want :
MFR_tot = [];
for ii = 1:20
data = load(['silomodresults',num2str(ii),'.mat']);
MFR_tot = [MFR_tot; data]; % concatenation
end
  3 Comments
Tessa Kol
Tessa Kol on 19 Oct 2020
Dear Mathieu,
I compressed silomoddata5.mat silomoddata6.mat and silomoddata20.mat into a zip file. You can download this using the link below (about 4 GB).
Is this oke?

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