Cause of invalid file identifier (no such file or directory)?

The following code (to read and open files) was written and tested with MATLAB R2012a on a windows7 operating system:

S = 'runoff.txt'; % Name of the file
D = '/gpfs/gpfs1/scratch/c77777/results/model_standalone_xc';
d = dir(fullfile(D,'Riffelsee*'));                         % directory list
%fmtS = ['%{dd.MM.yyyy-HH:mm}D' repmat('%*f',1,5) '%f'];   % Format 
fmtS = ['%s',repmat('%f',1,6)];                            % Format 
opt = {'HeaderLines',1,'CollectOutput',true};              % header
L=length(d);                                               % number of subfolders
YC=zeros(L,3);                                             % preallocate
for k = 1:L                                                % Iteration over sufolders
  [fid,message] = fopen(fullfile(D,d(k).name,S),'rt');     % open files
  if fid < 0
      disp(message);
      Z = [];
  else
      Z=textscan(fid,fmtS,opt{:});                             % read simulated values
  end
  fclose(fid);                                             % close
  dtS=Z{:,1};                                              % timestamp simulated (datetime)
  Qs=Z{:,2}(:,6);  ....

Opening and reading the files worked without errors.

Now the m-file should run on a cluster environment (Linux). A standalone version was created for this purpose.

If I submit this as a job the following error message appears:

_No such file or directory
Error using fclose
Invalid file identifier. Use fopen to generate a valid file identifier.

Error in ... (line fclose(fid))

MATLAB:FileIO:InvalidFid_

In the specified directory all files are included and the path appears to me as correct.

What could be the problem?

Answer 1

[Jan]

Obviously the path is not correct. You can check this easily:

File = fullfile(D, d(k).name, S);
[fid, message] = fopen(File, 'rt');     % open files
if fid < 0
    fprintf('Not found: %s\n%s\n', File, message);
    Z = [];
else
    Z=textscan(fid,fmtS,opt{:});         % read simulated values
    fclose(fid);   % <-- move inside the IF branch
end

You are searching for the pattern

 /gpfs/gpfs1/scratch/c77777/results/model_standalone_xc/Riffelsee*

In all these folders (or files?!) your search for the files:

 /gpfs/gpfs1/scratch/c77777/results/model_standalone_xc/Riffelsee*/runoff.txt

and the error message tells you, that one of these files does not exist. I'm sure Matlab has detected this carefully, so trust the message.

Note: Your code will fail, if you try to access dtS=Z{:,1}, if you have set Z=[].

[Glazio]

@Jan Simon: Thanks for your answer. There are no files missing, but some files have different names.