Error in my "for" loop?

Hi,

I basically need to run a nested (or series) loop. I need to run the permutations for a and b and run an external software that will use the values in a and b (first loop) and then c, s and t (second loop).

Let me explain that using numbers,

Assume that in the first loop we have:

a = [100 50];

b = [20 40];

And in the second loop we have:

c= [0 0];

s = [150 596]; % this has to be imported from a file. In this example, it is named "result_all.txt".

t= [0 0];

Now, the loop should read the first values of c, s and t in the first loop, i.e., 0,150 and 0. These values should be printed in a file named "Pulse.acc" vertically, i.e., in the following order:

0

150

0

Now, the second loop should start and read the values in a and b for all (four) permutations, i.e., (100 20), (100 40), (50 20) and (50 40). Each reading in the permutation should count the case number.

In a file named "MatParam8.0.tcl", the values of a and b along with their respective case number should be printed as follows for the first value of c, s and t in the first loop:

m1 100

m2 20

Case 1

--

m1 100

m2 40

Case 2

--

m1 50

m2 20

Case 3

--

m1 50

m2 40

Case 4

This should continue for the second values of the first loop.

Hence,

Case 1:

First loop:

0 150 0

Second loop:

100 200

Case 2:

0 150 0

Second loop:

100 40

Case 3:

0 150 0

50 20

Case 4:

0 150 0

50 40

------- The second reading from the first loop starts.

Case 5:

First loop:

0 596 0

Second loop:

100 200

Case 6:

0 596 0

Second loop:

100 40

Case 7:

0 596 0

50 20

Case 8:

0 596 0

50 40

An external file of OpenSees software will read all these inuput and their cases and print the output files accordingly.

I have tried to develop a code for that, but it does not seem to work. The code is shown below.

If you really focus on my code below, you may be able to link my explanation with what I am trying to do. This is because I have run the original nested "for loop" code successfully, but currently I need to do the opposite, i.e., run one value in the first loop and then excute all the permutations in the second loop, and then run the second value in the first loop, and then again excute all the puermutations in the second loop, and so on.

I hope I could explain that clearly, and please feel free to let me know if I need to explain it further.

The code:

close all; clc; clear all;
fin = 'result_all.txt';
s = dlmread(fin,'');
c=[0 0];
t=[0 0];
for m = 1:2;
    count = 0; %initialize
    
    fidP = fopen('Pulse.acc','w+');
    fidC= fopen('Case.tcl','w+');
    
    fprintf(fidP, '%d\n%d\n%d',c(m), s(m), t(m));
    fprintf(fidC, 'set case %d',count);
    
    fclose(fidP);
    fclose(fidC);
    
    a = [100 50];
    b = [20 40];
    count = count+1;
    for i=1:2;
        for j=1:2;
            
            line1 = ['set m1 ' num2str(a(i)) ';'];
            line2 = ['set m1 ' num2str(b(j)) ';'];
            fid=fopen('MatParam8.0.tcl','w');
            fprintf(fid,'%s\n',line1);
            fprintf(fid,'%s\n',line2);
            fid=fclose('all');
            
            !OpenSees Model.tcl
            
            
        end
    end
end

Answer 1

[Bob Thompson]

Currently your 'first' loop only loops through one set of indices, but you want it to loop through all c, s, and t values individually. You need more loops therefore.

close all; clc; clear all;
fin = 'result_all.txt';
s = dlmread(fin,'');
c=[0 0];
t=[0 0];
for m = 1:2;
    for n = 1:2;
        for p = 1:2;
            count = 0; %initialize
    
            fidP = fopen('Pulse.acc','w+');
            fidC= fopen('Case.tcl','w+');
            
            fprintf(fidP, '%d\n%d\n%d',c(m), s(n), t(p));
            fprintf(fidC, 'set case %d',count);
            
            fclose(fidP);
            fclose(fidC);
            
            a = [100 50];
            b = [20 40];
            count = count+1;
            for i=1:2;
                for j=1:2;
                    
                    line1 = ['set m1 ' num2str(a(i)) ';'];
                    line2 = ['set m1 ' num2str(b(j)) ';'];
                    fid=fopen('MatParam8.0.tcl','w');
                    fprintf(fid,'%s\n',line1);
                    fprintf(fid,'%s\n',line2);
                    fid=fclose('all');
                    
                    !OpenSees Model.tcl
                    
                    
                end
            end
        end
    end
end

As always with my answers, it may not be exactly what you need, so feel free to mess around with it as needed.

[Ismail Qeshta]

Hi Bob,

Many thanks for your answer and modification on the code.

I actually tried it, but I am not sure why the cases still keep counting 0, and hence they keep over-writing each other. This is the same problem that I was facing in the above loop.

[Bob Thompson]

Which variable, specifically, is counting zero?

[Ismail Qeshta]

Hi Bob,

The Case variable.

fprintf(fidC, 'set case %d',count);

Also, I notice that the overall loop does not end at 8 cases, but more than that.

I tried to modify the code and removed the case in the first "for" loop, but I still kepp getting the same error.

close all; clc; clear all;
fin = 'result_Full_all.txt';
s = dlmread(fin,'');
c=[0 0];
t=[0 0];
for m = 1:2;
    for n = 1:2;
        for p = 1:2;
            count = 0; %initialize
            
            fidP = fopen('Pulse.acc','w+');
            
            fprintf(fidP, '%d\n%d\n%d',c(m), s(n), t(p));
            
            fclose(fidP);
            
            a = [100 50];
            b = [20 40];
            count = count+1;
            for i=1:2;
                for j=1:2;
                    for k = ((i-1)*2)+ j;
                        
                        
                        line1 = ['set fc ' num2str(a(i)) ';'];
                        line2 = ['set fy ' num2str(b(j)) ';'];
                        line3 = ['set case ' num2str(k) ';'];
                        
                        fid=fopen('MatParamDyn.tcl','w');
                        fprintf(fid,'%s\n',line1);
                        fprintf(fid,'%s\n',line2);
                        fprintf(fid,'%s\n',line3);
                        
                        fid=fclose('all');
                        
                        !OpenSees Model.tcl
                        
                    end
                end
            end
        end
    end
end

[Bob Thompson]

Move 'count = count + 1;' inside the j loop.

Move 'fprintf(fidC, 'set case %d',count); inside the j loop as well.

Do you understand why I'm making these changes?

[Ismail Qeshta]

Hi Bob,

Thanks for your suggestions.

I assume you wanted these changes to be made on your code above, not the last one I posted.

Did you want to count the cases for each run in the second loop?

Actually, I did that but I am getting the following error message:

Error using fprintf

Invalid file identifier. Use fopen to generate a valid file identifier.

Error in Untitled9 (line 26)

fprintf(fidC, 'set case %d',count);

The updated code:

close all; clc; clear all;
fin = 'result_all.txt';
s = dlmread(fin,'');

c=[0 0];
t=[0 0];
for m = 1:2;
    for n = 1:2;
        for p = 1:2;
            count = 0; %initialize
            
            fidP = fopen('Pulse.acc','w+');
            fidC= fopen('Case.tcl','w+');
            
            fprintf(fidP, '%d\n%d\n%d',c(m), s(n), t(p));
            
            fclose(fidP);
            
            a = [100 50];
            b = [20 40];
            for i=1:2;
                for j=1:2;
                    
                    count = count+1;

                    fprintf(fidC, 'set case %d',count);

                    line1 = ['set fc ' num2str(a(i)) ';'];
                    line2 = ['set fy ' num2str(b(j)) ';'];
                    fid=fopen('MatParamDyn.tcl','w');
                    fprintf(fid,'%s\n',line1);
                    fprintf(fid,'%s\n',line2);
                    fid=fclose('all');
                    
                    !OpenSees Model.tcl
                    
                    
                end
            end
        end
    end
end

[Ismail Qeshta]

Update:

I have moved the fopen inside the "j" loop as well, and it worked.

However, the count starts at 0 and ends at 4 cases, and the output files keep over-writing each other.

[Bob Thompson]

Mmm, I forgot to mention you need to move the 'count = 0' in front of the m loop. It is over writing because it resets to zero each time the p loop begins again.

[Ismail Qeshta]

Hi Bob,

Just to avoid cofusion (because I myself was confused), I had to delete my above comments and post this final one instead.

I actually got the code to work.

Basically, the idea of having additional "for" loops did not really work, as it causes over-writing.

I just kept one "for" loop for the first loop, and just moved the count=0 before the first loop and count = count+1;

fidC= fopen('Case.tcl','w+');

fprintf(fidC, 'set case %d',count);

inside the second loop.

Thank you very much for all your time and help.

Actually, with you I got to learn a lot about coding, especially how to deal with complex nested "for" loops like that.

Thank you very much again.