Evaluating the Error Function

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  • เผยแพร่เมื่อ 24 ธ.ค. 2024

ความคิดเห็น • 43

  • @minhtrinh7440
    @minhtrinh7440 5 ปีที่แล้ว +9

    Background music is so on point. Math sure is frightening ;)

    • @lesnyk255
      @lesnyk255  5 ปีที่แล้ว +4

      I heard the music as more other-wordly than frightening - though mathematical notation can certainly be intimidating! Right now I'm struggling with a text on numerical analysis,, trying to create practical algorithms from rigorously precise derivations....

  • @christnightingale1658
    @christnightingale1658 8 ปีที่แล้ว +12

    What a background music!

  • @吳靖宇-b9n
    @吳靖宇-b9n 7 หลายเดือนก่อน

    Thank you very much, this video let me know more how to calculate error function and how the z-table graph come from. Just want to remind that it is ease to miss the "x" before the summation signal in the final formula at 3:02.

  • @manbearbukk
    @manbearbukk 7 ปีที่แล้ว +6

    The content of this video was so great! I realy liked that you didn't skip any of the important steps (teachers always do)

    • @lesnyk255
      @lesnyk255  7 ปีที่แล้ว

      +Alexander Bukk - thanks, I think the intermediate steps are important because it's not always obvious where the algebra will lead you. I don't go into as much detail as blackpenredpen (an excellent channel), but I try to make the thought processes clear.

  • @stankossovskiy816
    @stankossovskiy816 ปีที่แล้ว +1

    0:17 Base Definition
    3:25 Taylor series formula
    4:25 Rk-th formula
    6:00 algorithm

  • @deanw8206
    @deanw8206 6 ปีที่แล้ว +3

    What is the music called? It would be great to play while studying.

    • @lesnyk255
      @lesnyk255  6 ปีที่แล้ว +3

      It's by Tangerine Dream - last slide gives full credit to the band and the recording it was taken from.

  • @johanndohmann1281
    @johanndohmann1281 ปีที่แล้ว

    Wow, thank you. you present a great piece of math. good expaination. I myself need the error function in the context of the mathematics of diffusion, such as instationary heat transfer with the Heavyside boundary condition. yes, modern programs know to evaluate the erf(x). but now i feel better because now i know as well. Thank you for that gift. it must have been very exciting to find this way to solve the problem. Best wishes from oversea.

    • @lesnyk255
      @lesnyk255  ปีที่แล้ว

      You're most welcome, and thank you for the kudos! I suppose Taylor series are the basis for a lot of approximation techniques, but I liked the trick of finding a common ratio between successive terms of an infinite series, something I'd picked up many years earlier in a Diff Eq class. Best of luck in your endeavors!

  • @fosheimdet
    @fosheimdet 4 ปีที่แล้ว

    The music is good. Far better than a lot of the upbeat and distracting crap you find on many other videos.

  • @wduandy
    @wduandy 6 ปีที่แล้ว +1

    Man you're amazing and i love this Song!

    • @lesnyk255
      @lesnyk255  6 ปีที่แล้ว

      thank you, glad you found it interesting. Nowadays even Excel has an intrinsic erf(x) (though I think they call it something else), but back then we had to roll our own.

    • @wduandy
      @wduandy 6 ปีที่แล้ว

      I did with python!
      And your idea to find the r = Ak/Ak-1 was amazing.
      I did that for sin(x), cos(x) and etc...
      Look how easy it was:
      def erf(x):
      T = 1
      Sum = 1
      for k in range(1,10000):
      T = T*(-x**2)*(2*k-1)/(2*k**2+k)
      Sum += T
      return Sum*2/pi**0.5

    • @wduandy
      @wduandy 6 ปีที่แล้ว

      Do you have facebook ?

    • @wduandy
      @wduandy 6 ปีที่แล้ว

      I found that 10k iterations was more the enough hahaha

  • @NarutoUzumaki-qf3lw
    @NarutoUzumaki-qf3lw 8 ปีที่แล้ว +4

    The music make you focus intensively THANK YOU

    • @lesnyk255
      @lesnyk255  8 ปีที่แล้ว +2

      Thank you, that was the intent. It's too bad others who couldn't see that were put off by it.

    • @FunYouLeh
      @FunYouLeh 8 ปีที่แล้ว

      personal preferences, just that it's the minority who likes it..

    • @lesnyk255
      @lesnyk255  8 ปีที่แล้ว +1

      Melvin Ang
      In my opinion, four or five complaints out of over 2300 views do not constitute an overwhelming majority.

  • @tag_of_frank
    @tag_of_frank 7 ปีที่แล้ว +5

    The music was great. Make an abstract algebra playlist with a similar style and I will watch ahaha

  • @mathnerdaid2770
    @mathnerdaid2770 4 ปีที่แล้ว

    Does anyone know if the first Z tables were made with something like this? I've tried finding a probability from the normal distribution using the error function power series alone, and it was labor-intensive for anything not close to the center. I think there must have been a better way, similar to this.

    • @lesnyk255
      @lesnyk255  4 ปีที่แล้ว

      I don't know, but I would guess some kind of numerical integration like Simpson's or quadrature was used

    • @mathnerdaid2770
      @mathnerdaid2770 4 ปีที่แล้ว

      @@lesnyk255 Thanks. I'll just go with this. Amazing how a calc 2 technique can circumvent such a huge problem. I'm going to do the same thing to use for integral of e^u^2 instead of e^u^2/2 since that seems to be the most prevalent version of erf currently.

    • @lesnyk255
      @lesnyk255  4 ปีที่แล้ว

      @@mathnerdaid2770 Yes, e^[(u^2)/2] is pretty specific to the normal distribution in statistics. The version you propose is the general case.

  • @BigHeartBreak93
    @BigHeartBreak93 8 ปีที่แล้ว +3

    that music though...

  • @theunknown0154
    @theunknown0154 4 ปีที่แล้ว

    What's with the bgm???!!!

  • @mathiasbuder1773
    @mathiasbuder1773 5 ปีที่แล้ว

    Thanks, very nice job!!

  • @teriyakichicken1848
    @teriyakichicken1848 8 ปีที่แล้ว +2

    What level math is this??

    • @lesnyk255
      @lesnyk255  8 ปีที่แล้ว +1

      Some calculus (Taylor/MacLaurin series, integration) - mostly algebra

  • @sophia2928
    @sophia2928 3 ปีที่แล้ว

    The music omg.

  • @tianshuma241
    @tianshuma241 9 ปีที่แล้ว +10

    thanks for this, but the BGM......

    • @lesnyk255
      @lesnyk255  9 ปีที่แล้ว +1

      +Tianshu Ma
      Sorry - BGM = ???

    • @tianshuma241
      @tianshuma241 8 ปีที่แล้ว +1

      sorry, i mean the back ground music is like a horror movie. video is excellent by the way.

    • @grigoryshepelev8149
      @grigoryshepelev8149 7 ปีที่แล้ว +2

      I've been waiting for scary face to jump out of screen

  • @mrnarason
    @mrnarason 8 ปีที่แล้ว +1

    apparently this is a solution to my quantum hw problem but I've never heard of the erf func before so wtf.

    • @lesnyk255
      @lesnyk255  8 ปีที่แล้ว +1

      It figures prominently in statistics, defining the Normal Distribution.

    • @woodenfloor3131
      @woodenfloor3131 7 ปีที่แล้ว +2

      I don't want to use the shitty chart my teacher gave me and this is how I ended up here

  • @AmBhushan303
    @AmBhushan303 6 ปีที่แล้ว +3

    The music is so creepy

  • @budasfeet
    @budasfeet 6 ปีที่แล้ว +1

    This is awesome, some good applied mathematics here. This can definitely be used in microcontroller to speed up processing.

  • @izabellanovella5019
    @izabellanovella5019 4 ปีที่แล้ว

    THANK YOU!