Strange error importing matrices in a loop

Hello,

im importing 100 matrices in a loop and performing some calculations on every single one matrix before exporting and concatenating end results. For some reason, matrix #94 is not the expected 900x6 size but just the single value '48000'. Do you know what causes this? The same script (see partially below) has been fully working in the past, but not anymore. I have tried renaming and/or remaking that particular matrix from scratch, without success. If I isolate the matrix and try to import it outside a loop, that works... so it seems to only be failing in the loop.

Thanks in advance!

for i=1:100    % loop over files

   if i < 10            % identify filenames per iteration
g=num2str(i);
num = strcat({'00'},{g});                                                        
stgnum=char(num);          
   elseif i < 100
g=num2str(i);
num = strcat({'0'},{g});                                                        
stgnum=char(num);       
   else         
g=num2str(i);
num = strcat({g});         
stgnum=char(num);
   end
tracks_file = ['AA','#',stgnum,'.mat'];
dir_tracks = ['F:\any directory',tracks_file];
% data is imported below, one sequence each iteration of the main loop
A = importdata(dir_tracks);
end

[Geoff Hayes]

Jasper - what happens if you use the MATLAB debugger and put a breakpoint in the code so that it pauses on the 94th iteration of the for loop? What is assigned to dir_tracks and does it make sense?

[Jasper]

Hi Geoff,

as for all the other iterations, the same directory is still being assigned (the matrices are input from the same dir), so that is not the problem. Thanks for your reply, any other ideas?

Jasper

[Stephen23]

Use sprintf instead of that awkward concatenation and if-|else| operation, and use fullfile to generate the full path string:

myPath = 'F:\any directory';
myForm = 'AA#%03d.mat';
for k = 1:100
    myName = sprintf(myForm,k);
    myFull = fullfile(myPath,myName);
    %A = importdata(myFull);
end

Answer 1

[Walter Roberson]

Given that set of conditions, my suspicion would be that importdata() is leaking open files -- that is, failing to close files after it opens them. As an experiment, right after your importdata() line, add

close('all');