• sp3ctr4l@lemmy.zip
    link
    fedilink
    English
    arrow-up
    71
    arrow-down
    1
    ·
    edit-2
    3 months ago

    https://en.m.wikipedia.org/wiki/Saddle_point

    Basically, its a mathematical function where if you start at 0,0, you might falsely believe you are at the (or a) maximum or minimum of the function, as the slope at 0,0 is 0.

    But, if you go any direction in the x axis, your function value rises, any direction in the y axis, your function value falls.

    Thus a saddle point is an illusory, false impression of being at the extreme extent of a function, when in fact you are not.

    The idea is that there is more to determining if you’re truly at a global max or min of a function than only finding a single point where the slope is 0.

    Edit: This comment if mine has been sitting at 69 upvotes for a few days now, so uh… obligatory joke about taste testing each others saddle points or something, I don’t know.

    • Ekky@sopuli.xyz
      link
      fedilink
      English
      arrow-up
      2
      ·
      edit-2
      3 months ago

      Hurr hurr, I’m gonna plot f(x,y)=x2+y3 where y=x for x limit inf. Checkmate science!

      Edit: the graph isn’t actually linear, man, and here I just thought it’d be that easy. :(

      • sp3ctr4l@lemmy.zip
        link
        fedilink
        English
        arrow-up
        1
        ·
        2 months ago

        I mean … sure?

        Just have a continuous graph that looks like two little hills, but far away there is an even bigger mountain.

        You’d then have two saddle points somewhere between those two little hills and the big mountain, though they might not be as visually distinctive as the image here.

        Don’t think I said you cannot have local maxima that are not saddle points.

        Hell, even the image of the graph shown could be some kind of small scale topographically phenomenon, and what look to be going off to infinity in this small scope might actually top off as local maxima.

        The actual function isn’t shown.

        It could be very simple, or it could be an absurdly complex polynomial that just looks like the simpler version when you zoom in.

        Something like a 3d version of this:

          • sp3ctr4l@lemmy.zip
            link
            fedilink
            English
            arrow-up
            2
            ·
            2 months ago

            No, I explained what a saddle point is and how a saddle point can be misidentified as a local or absolute maxima or minima if all you do is look for a point where the slope is 0.

            … anyway, is this a glitch on my end or … how do most of your comments have 0 upvotes… and also 0 downvotes?

            … I thought lemmy automatically gives every post 1 upvote by default.