• neidu3@sh.itjust.works
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    2 days ago

    Could one of you scholars please explain the joke for us smoothbrains who don’t get it? All I see is a boolean matrix, and I’m not even sure that is correct.

    • pseudo
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      23 hours ago

      That matrix of zeros with one in diagonal is called the matrix of identity.
      It is famous because when doing multiplication on matrix or vector, it acts likes 1 on “normal” number:
      x times 1 is x anyMatrix times Identity is anyMatrix.

        • pseudo
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          23 hours ago

          You are right. I will correct it.

            • pseudo
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              19 hours ago

              I need to freshen up on my linear algebra. I don’t remember on which sense it goes but I think if you swap the factors, you’ll have to you transpose the matrix x to keep the same result.

        • MBM@lemmings.world
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          22 hours ago

          Huh? Identity times anyMatrix is also anyMatrix. The matrix just has to have the right dimensions

    • zqwzzle@lemmy.ca
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      2 days ago

      A square matrix with the ones in the diagonal is called the identity matrix

    • lugal@lemmy.dbzer0.com
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      2 days ago

      It’s an identity matrix. You multiple a vector with it and the result is still the same (identical) vector