• neidu3@sh.itjust.works
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    1 month 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.

    • zqwzzle@lemmy.ca
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      1 month ago

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

    • lugal@lemmy.dbzer0.com
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      1 month ago

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

    • pseudo@jlai.lu
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      14 days 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@jlai.lu
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              1 month 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
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          1 month ago

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

  • MichaelScotch@lemmy.world
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    1 month ago

    Identity theft is not a joke, Jim. Millions of families suffer every year. Also one that the internet gets wrong all the time: “dude, this is a Wendy’s”, not “sir this is a Wendy’s”