[Octave-bug-tracker] [bug #62152] Textscan fails in rare occurences

[anonymous]

URL:
  <https://savannah.gnu.org/bugs/?62152>

                 Summary: Textscan fails in rare occurences 
                 Project: GNU Octave
            Submitted by: None
            Submitted on: Tue 08 Mar 2022 02:27:28 AM UTC
                Category: Octave Function
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Matlab Compatibility
                  Status: None
             Assigned to: None
         Originator Name: maiky76
        Originator Email: 
             Open/Closed: Open
                 Release: 6.4.0
         Discussion Lock: Any
        Operating System: Microsoft Windows

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Details:

Bug filed from:
https://octave.discourse.group/t/help-on-textscan-rare-occurrences-of-errors/2332/7

I have been having some very rare occurrences (about 0.15% based on 15k
iterations) where the following code does not work.
The files are all generated by a single program and are supposed to strictly
follow the same format.

In some instances the code fails to properly read the content of the file and
stop somewhere for no apparent reason.
The equivalent function in Matlab never fails.

4 files examples are attached to test,
Spectrum_ABEC_OK.txt load with no issue
Spectrum_ABEC_KO.txt only load with the revised code
Spectrum_ABEC_3.txt stops line 27
Spectrum_ABEC_4.txt stops line 5


clear all
close all
clc
Pref       = 2e-5;

% EmptyData = 25 about 0.1%
% Total_iter = 24122 37h
% size(SPL) should return 37x40

 Path2filename   = 'Spectrum_ABEC_OK.txt'; % Vast majority of the files 
% Path2filename   = 'Spectrum_ABEC_KO.txt'; % 
% Path2filename   = 'Spectrum_ABEC_3.txt'; % stops line 27
 Path2filename   = 'Spectrum_ABEC_4.txt'; % stops line 5 

%
------------------------------------------------------------------------------
% Read first part of the file never fails
delimiter  = ' ';
startRow   = 39;
endRow     = 78;
formatSpec = '%f%f%f%[^\n]';

fileID     = fopen(Path2filename,'r');
dataArrayZ = textscan(fileID, formatSpec, endRow-startRow+1, 'Delimiter',
delimiter, 'MultipleDelimsAsOne', true, 'HeaderLines', startRow-1,
'ReturnOnError', false, 'EndOfLine', '\n');
fclose(fileID);
FreqZ      = cell2mat(dataArrayZ(1)); 
ZRe        = cell2mat(dataArrayZ(2));
ZIm        = cell2mat(dataArrayZ(3));
RadZ       = [ZRe ZIm];
% Clear temporary variables
clearvars delimiter startRow endRow formatSpec dataArrayZ ans;


if exist('OCTAVE_VERSION', 'builtin') == 0 

  delimiter  = ' ';
  startRow   = 105;
  endRow     = 144;
  formatSpec =
'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%[^\n\r]';
  fileID     = fopen(Path2filename,'r');
  dataArray  = textscan(fileID, formatSpec, endRow-startRow+1, 'Delimiter',
delimiter, 'MultipleDelimsAsOne', true, 'TextType', 'string', 'HeaderLines',
startRow-1, 'ReturnOnError', false, 'EndOfLine', '\r\n');
  fclose(fileID);

  Freq           = cell2mat(dataArray(1)); % should be indentical to FreqZ
  SpectrumABEC   = cell2mat(dataArray(2:end-1));
  [~, col]       = size(SpectrumABEC);
  NbSpectra      = col/2

else

  delimiter  = ' ';
  startRow   = 105;
  endRow     = 144;

  %
------------------------------------------------------------------------------
  % original
   formatSpec =
'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%[^\n]';
   fileID     = fopen(Path2filename,'r');
   dataArray  = textscan(fileID, formatSpec, endRow-startRow+1, 'Delimiter',
delimiter, 'MultipleDelimsAsOne', true, 'HeaderLines', startRow-1,
'ReturnOnError', false, 'EndOfLine', '\n');
   fclose(fileID);
   Freq           = cell2mat(dataArray(1));
   SpectrumABEC   = cell2mat(dataArray(2:end-1));
   [~, col]       = size(SpectrumABEC);
   NbSpectra      = col/2;

  %
------------------------------------------------------------------------------
  % Octave help
  %  formatSpec =
'%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f%f';
  %  fileID     = fopen(Path2filename,'r');
  %  dataArray  = textscan(fileID, formatSpec, endRow-startRow+1, 'Delimiter',
delimiter, 'MultipleDelimsAsOne', true, 'HeaderLines', startRow-1,
'ReturnOnError', true, 'EndOfLine', '\r\n');
  %  fclose(fileID);
  %  
  %  Freq           = cell2mat(dataArray(1));
  %  SpectrumABEC   = cell2mat(dataArray(2:end));
  %  [~, col]       = size(SpectrumABEC);
  %  NbSpectra      = col/2;
  %
------------------------------------------------------------------------------

  [~, col]       = size(SpectrumABEC);
  NbSpectra      = col/2 % should return 37x40

end

for k = 1:NbSpectra
  SPL(:,k)       = 20*log10( abs( ( ( SpectrumABEC(:,2*k-1) +
1i*SpectrumABEC(:,2*k) ) /sqrt(2) ) / Pref ) ); % RMS value
  deg(k,1)       = (k-1)*5;
end

SizeSPL = size(SPL)

figure()
  subplot (211)
       semilogx(FreqZ, RadZ(:,1), 'k') 
       hold on 
       semilogx(FreqZ, RadZ(:,2), 'k--') 
       grid on 
       ylabel('Z')
       xlabel('Frequency [Hz]')
       legend('ReZ', 'ImZ')
       title('Waveguide Z'); 
  subplot (212)
       semilogx(Freq, SPL)  
       grid on
       ylabel('SPL [dB]')
       xlabel('Frequency [Hz]')
       legend('SPL 5 deg step')
       title('Waveguide SPL'); 




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File Attachments:


-------------------------------------------------------
Date: Tue 08 Mar 2022 02:27:28 AM UTC  Name: Spectrum_ABEC_OK.txt  Size: 66KiB
  By: None

<http://savannah.gnu.org/bugs/download.php?file_id=52968>
-------------------------------------------------------
Date: Tue 08 Mar 2022 02:27:28 AM UTC  Name: Spectrum_ABEC_3.txt  Size: 66KiB 
 By: None

<http://savannah.gnu.org/bugs/download.php?file_id=52969>
-------------------------------------------------------
Date: Tue 08 Mar 2022 02:27:28 AM UTC  Name: Spectrum_ABEC_KO.txt  Size: 66KiB
  By: None

<http://savannah.gnu.org/bugs/download.php?file_id=52970>
-------------------------------------------------------
Date: Tue 08 Mar 2022 02:27:28 AM UTC  Name: Spectrum_ABEC_4.txt  Size: 66KiB 
 By: None

<http://savannah.gnu.org/bugs/download.php?file_id=52971>

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