Writing/Loading data that has runs 2 for loops

Hi,

Lvals = 1:10;
xivals = 1:10;
%
tarray = 1:20;
nt = length(tarray);
%
lxi =length(Lvals);
nxi =length(xivals);
%
for il=1:lxi
    pars.L= Lvals(il);
    Lval=pars.L;
    for ixi=1:nxi
        pars.xi = xivals(ixi);
        xival=pars.xi;
        % 
        % writing activity to terminal
        disp(['Run started with L = ' num2str(pars.L), ' xi = ' num2str(pars.xi)])
        
        % creating file name with the activity value
        filename = ['sol_' num2str(il), num2str(ixi)];
        
        for it = 1:nt
            u(ixi, il, :,:,it)
        end
    end
end


disp('Saving data...')
save(['C...' filename '.mat'], 'u');

It is expected that u is 5 dimensional, so that u is u(10, 10, :, :, nt). In my folder I have 100 entries for 10 different xi and 10 different L.

:, :, is the x and y array.

I tried:

disp('loading data')
filepath = 'C:folder';
datafilename = dir(fullfile(filepath,'*.mat'));
full_file_names = fullfile(filepath,{datafilename.name});

datafilename = natsortfiles(datafilename);
%
for n = 1:numel(datafilename)
    F = fullfile(datafilename(n).folder,datafilename(n).name);
    datafilename(n).data = load(F);
end
data = [datafilename.data];

This code is loading all the 100 files.

How do I load this data such that at the end I can extract u(xi, L, :, :, nt) such that xi=1:10 and L=1:10

Not xi=100 and L=100.

Answer 1

[Nipun]

Hi University,

I understand that you are trying to save multiple files and loading data from specific files using for loops, but the wrong file is being read by MATLAB. Based on the provided information, I can recommend few fixes that may solve this issue.

In the attached code, you are assigning the variable "filename" in each iteration, merely changing its value. I believe you intend to create an array of file names which will store the variable "u" value.

Consider the following modified code, with comments

Lvals = 1:10;
xivals = 1:10;
%
tarray = 1:20;
nt = length(tarray);
%
lxi =length(Lvals);
nxi =length(xivals);
%% Create an empty matrix of strings
filename = strings(lxi, nxi);
%
for il=1:lxi
    pars.L= Lvals(il);
    Lval=pars.L;
    for ixi=1:nxi
        pars.xi = xivals(ixi);
        xival=pars.xi;
        % 
        % writing activity to terminal
        disp(['Run started with L = ' num2str(pars.L), ' xi = ' num2str(pars.xi)])
        
        % creating file name with the activity value
        %% Save the filename in the variable
        filename(il,ixi) = "sol_"+num2str(il)+ num2str(ixi);
        
        for it = 1:nt
            u(ixi, il, :,:,it)
        end
  
    end
end

%% Save the specific slice of "u" in a .mat file
for i =1:lxi
    for j=1:nxi
        temp = u(i,j,:,:,nt);
        save(filename(i,j)+".mat","temp",'-mat');
    end
end

This code will generate 100 .mat files with specific variable values.

To read the specific slices of "u", just read the corresponding file name. For instance if you want to load "u(2,30,:,:,nt)"

load 'sol_23'

This command will load the intended variable in your workspace. Hope this helps

Regards,

Nipun