Automatic building of an array

Hey all,

Below is my function. I need to build the array automatically for the user input.

function suri1(Measuring_Data(:,7))
%User input
X = {1, 2,'Node1'; 3, 4, 'Node2'; 5, 6, 'Node3'};         % different for different users
n = 10;
d_T= 1 ;
t = 200;
S = load('Measuring_Data.mat');
f = 0:d_T:(t-1)*d_T;

p = cell2mat(X(:,1));
q = cell2mat(X(:,2));
disp(p);
disp(q);
T_Vorgabe = zeros(1,length(f));    % Row vector
for plotnumber = 1:n
    c = find(p == plotnumber,1);
    if ~isempty(c)
        c = plotnumber;
        for plotnumber1 = 1:n
            c1 = find(q == plotnumber1,1);
            if ~isempty(c1)
                c1 = plotnumber1;
                T_Vorgabe{c}(1,:) = S(c1,1);              % May be worng syntax , All the values of the measuring data should be copied to T_Vorgabe as a row %vector or row cell array, c is the user input number to build the vector or cell array of different names
           end
        end
    end
end
figure
hold('on')
for plotnumber2 = 1:n
c2 = find(p == plotnumber,1)
if     ~isempty(c2)
c2 = plotnumber;
plot(f(1:15:end)/200, T_Vorgabe{c2});               % Slover should plot all the values of T_Vorgabe(row vector or row cell array.
end
end
end

Here T_Vorgabe{c2} will be cell array. Now while plotting the T_Vorgabe solver should get the all the values stored from the respective cell arrayT_Vorgabe{c2}.

My questions are,

How to make T_Vorgabe as a row vector, or row cell array of different names according to user input?

Like below

T_Vorgabe{1}=[1,2,3,...,2920]

T_Vorgabe{2}=[2921,2922,2923,...,5840] etc

Any suggestions and answers are most welcomed.

Thanks in advance

[Stephen23]

"Any suggestions... are most welcomed."

Do NOT do this!

Do NOT mix meta-data into code: meta-data is data, so it should be stored in a variable, not in the variable's name. By forcing meta-data into variable names you will force yourself into writing slow, complex, buggy, obfuscated code which is hard to debug. Read this to know why:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

Note that you should load the file data into an output variable (which is a scalar structure):

S = load(...)

and then access its fieldnames:

https://www.mathworks.com/help/matlab/matlab_prog/generate-field-names-from-variables.html

[surendra kumar Aralapura mariyappa]

Hello sir,

I changed the code according to your suggestion.

But I didn't get the answer to my real question.

[Bob Thompson]

Your for loop seems to be set up correctly to index the information you want into different cells, so I don't see a major problem with the concept you are employing. Can you be more specific about what is wrong with the output you're getting.

Are you getting any errors? If so, please copy the entire error message for us.

If you are not getting any error messages, then how do you know the output is incorrect? What are you receiving, and how does it differ from what you expect?

[Stephen23]

"I changed the code according to your suggestion."

Not really, because your edited question shows that you ignored the parts of my comment where I wrote "...which is a scalar structure... then access its fieldnames..." Why are you using indexing into a scalar structure? Why are you ignoring the structure's fieldnames?

"But I didn't get the answer to my real question. "

The only question you asked was "How to make T_Vorgabe as a row vector, or row cell array of different names according to user input." I did not answer that question (these are comments, not answers (see below for answers)), but instead I wrote a comment explaining why this approach is not recommended. I also showed you how it can be avoided. My aim is to help you write better code, by avoiding the inefficient approach that you are attempting.

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

[surendra kumar Aralapura mariyappa]

@Nbob ''Can you be more specific ''

T_Vorgabe{c}(1,:) = S(c1,1);

I just need to know whether it is correct or not!. Why because, currently I don't have measuring data with me. So I need to build it for the future use.

Let's be more specific.

I have a matrix S contains measuring data. So I need to copy the specific row of S into T_Vorgabe according to user input. For an example, If the user want to copy row 2 5 9 to T_Vorgabe, T_Vorgabe should be a row vector or row cell array of different names. Like below

T_Vorgabe{2}(1,:)

T_Vorgabe{5}(1,:)

T_Vorgabe{9}(1,:)

Here the problem is, Whether the code is correct or not! Both T_Vorgabe{c}(1,:) = S(c1,1); and T_Vorgabe{2}(1,:) .

Second question is How to access the indicies of element of cell array?

For an example.

X = {1, 2,'Node1'; 3, 4, 'Node2'; 5, 6, 'Node3'};

p = cell2mat(X(:,1));

Now I need to access the indicies of cell element of first column.

I hope my explanation is okay now to get the answer.

Thanks in advance.

[surendra kumar Aralapura mariyappa]

@Stephen Cobeldick.

Now I realized the importance of your suggestion after I ran my program. It is taking too much time to do compilation. It is the time for me to make my code according to your suggestion.

Anyways thank you.

Answer 1

[Bob Thompson]

'T_Vorgabe{c}(1,:) = S(c1,1);

I just need to know whether it is correct or not!. '

As I mentioned before, the concept is sound, and it should produce something like what you are looking for. I cannot tell you if it is 'correct' because minor adjustments may be needed to personalize the code to your specific dataset. I suspect this line will not actually have to be changed, but perhaps your definition of c and c1 will need to be changed. That is something you will have to tackle though when you have an actual sample of data to work with. That's just how debugging works.

'Second question is How to access the indicies of element of cell array?'

For information on how to work with cell indices I recommend this link. If you still need additional help, please be more specific.

[surendra kumar Aralapura mariyappa]

@ Nbob, ' please be more specific.'

I think at least I will get the solution to my problem now.

%T1(:,1) = T1(:,1)+ 20; % Adding the ambient temperature

%f = 0:d_T:(t-1)*d_T; %d_T is step time

% Here d_T = 1 and t = 200 iterations. %T1 is a temperature vector for 200 iterations

load('Measuring_Data.mat');

[f,T] = Samplemodel_Instat('Measuring_Data.mat');

[Lambda, A, B, D,V,H, Rho,cP,P, M, A1,O, X, M_1] = Matrix_Samplemodel;

% X = { 3 6 'Node1': 4 9 'Node2'}; Like this

p = cell2mat(X(:,1));

q = cell2mat(X(:,2));

disp(p);

disp(q);

n = size(A,1);

T_Vorgabe = zeros(1,length(f)); % I am not sure whether the preallocation is correct or not!.

for plotnumber = 1:n

c = find(p == plotnumber,1);

if ~isempty(c)

c = plotnumber;

for plotnumber1 = 1:n

c1 = find(q == plotnumber1,1);

if ~isempty(c1)

c1 = plotnumber1;

T_Vorgabe{c}(1,:) = Measuring_Data(c1, 1); % Here Measuring_Data should be copied to %T_Vorgabe each time with new variable name according to the user input.

end

end

end

end

%then all the T_Vorgabe{c} should be plotted.

plot(f(1:200:end)/3600,T_Vorgabe{c}(1:200:end),'Color','k','LineWidth',2,'LineStyle','--');

end

I hope now it is understandable.

this is the error I am getting:

"Cell contents assignment to a non-cell array object.

Error in suri1 (line 22)

T_Vorgabe{c}(1,:) = Measuring_Data(c1, 1);"

I just need to copy the measuring values to new T_Vorgabe variable like T_Vorgabe.1, T_Vorgabe.2 each time and plot it.

Any suggestions and answered are most welcomed

Thanks in advance.