zl.median bug or am I mis-using?


    Apr 28 2022 | 8:48 pm
    Hi, just discovered this: I'm using zl.median to smooth out sensor values. when I send a list of [1,1,359,359]
    I get an output of 180.
    Is this the expected result? I thought median value had to be a member of the original list?
    Max Patcher
    In Max, select New From Clipboard.
    max 8.1.11 osx 11.6.5

    • Apr 28 2022 | 11:32 pm
      If you have an even count of items you get the mean of the 2 center values after sorting. Try with 5 values and you get a member.
    • Apr 29 2022 | 1:17 am
      Ah thanks! I can see how that's a difficult edge case. Not great for my application, but this gives me a hint for a workaround. Wonder if it's worth mentioning in the help file?
    • Apr 29 2022 | 4:13 am
      it should offer three modes: "in case of stalemate output higher one, lower one, or the mean of the two candidates."
    • Apr 29 2022 | 8:16 am
      Wonder if it's worth mentioning in the help file?
      I think not because that's what everybody expects from a median. Here's a custom solution that lets you get the lower or higher one.
      Max Patcher
      In Max, select New From Clipboard.
    • Apr 29 2022 | 1:57 pm
      one of the most mid values in a list is not less the central value of the list than a fictional, additional central value, which is not even part of the original list. but i´ve looked it up, 11Olsen is right. that is how it is usually done and defined in math. what is more important (than my unreasoned attempt to declare the median to have to be a list member) is why we measure the median and what are its properties. then it suddenly makes sense.
    • Apr 29 2022 | 2:07 pm
      Thanks! With a bit more research I see now that is the expected outcome. I didn't know that. And thanks for the proposed solution!
    • Apr 29 2022 | 4:54 pm
      of course one problem remains: when you are in an integer-only world (such as midi note numbers), you might need to decide wether to round up or down in case the mean between the higher median and the lower median ends up beeing 117.5