I am not sure if this is the right website to ask this question but I cant figure out where else to get the answer so, please, dont be mad :-)

As my bachelor thesis/project, I am trying to construct a short-scale search engine using TF-IDF measure. At the moment I am working on the construciton of my index. Usually term-document matrix is used where the rows represent terms (words) and columns are documents (webpages) on that pages. My question is - why is this better than using document-term matrix (this one would be just a transpostion of the term-document one.

It appears to me, that adding a new page to this matrix is more common operation and adding new row slightly easier than adding new column. I would be glad, if you could suggest me any article concerning this topic, because I have found none so far.

Thank you all your answers in advance!


closed as off topic by Ittay Weiss, Davide Giraudo, Alexander Gruber, Asaf Karagila, Thomas Feb 15 '13 at 13:53

Questions on Mathematics Stack Exchange are expected to relate to math within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here. If this question can be reworded to fit the rules in the help center, please edit the question.

  • 1
    $\begingroup$ If the mods think it appropriate, they might migrate your question to Cross Validated or Stack Overflow. $\endgroup$ – russellpierce Feb 15 '13 at 9:46
  • $\begingroup$ A term document matrix is just the transpose of a document term matrix. Or at least that's how most text mining software that I'm familiar with deals with it. $\endgroup$ – Brandon Bertelsen May 28 '16 at 4:42

I think the answer here is going to be convention. The Term-Document matrix method I'm familiar with is called LSA (Latent Semantic Analysis). The data reduction techniques used singular value decomposition reduces the number of columns (documents) but keeps the number of rows (words). In the early stages of thinking about these things the identity of the document was far less important than the identities of the words.

  • $\begingroup$ Fair enough, there is probably no deeper reason, thx. $\endgroup$ – Smajl Feb 15 '13 at 10:16

Not the answer you're looking for? Browse other questions tagged or ask your own question.