Attempted to access tfMatrix(0,1); index must be a positive integer or logical. Error in modellingPLSA (line 25) tfMatrix(w​ordNumber,​documentNu​mber) = tfMatrix(w​ordNumber,​documentNu​mber) + 1;

data = dlmread('fichier.txt','\t');
[m,n] = size(data);

doc_length = 4;         
documents = floor((44*60+12)/doc_length);     

windowSize = 20;
words = (280/windowSize+1)*(360/windowSize)*5*2;
FramesForWords = cell(words,documents);
for i=1:words
  for j=1:documents
    FramesForWords{i}{j} = [];
  end
end
 tfMatrix = zeros(words,documents);
 for row=1:size(data,1)
     i = data(row,1);
     j = data(row,2);
     frame = data(row,3);
     opticalFlow = data(row,4);
     blobSize = data(row,5);
     documentNumber = uint16(floor(frame/(25*doc_length)))+1;
     wordNumber = ((i/windowSize)*18+(j/windowSize))*10  + opticalFlow*2 + blobSize + 1;
     tfMatrix(wordNumber,documentNumber) = tfMatrix(wordNumber,documentNumber) + 1;
   FramesForWords{wordNumber}{documentNumber} = [FramesForWords{wordNumber}{documentNumber};frame];
     if documentNumber == documents                   
         break
     end
 end

[Walter Roberson]

As we do not have the data from the file, we have no reason to expect that wordNumber will come out as a positive integer.