Talk:Gaussian function

Multivariate gaussian

An undefined variable called B keeps showing up inside the "Multivariate gaussian" paragraph. I have no idea if it is simply: B = A, or if there is something subtle going on here, but either we need to add a definition for B, or just remove it from the math. — Preceding unsigned comment added by 2001:620:600:6000:ECDF:3A24:4CBA:7595 (talk) 11:47, 15 April 2013 (UTC)

I believe you are right, I just let B = A in one place. But latter, there is a B that is defined as B = A + A' and I didn't yet figure out what it means. Bdmy (talk) 12:23, 15 April 2013 (UTC)

What's worse, I believe the definition of the Gaussian including the shift vector is wrong, or at least not explained enough. The definition used in the multivariate normal is something along the lines of $n*e^{-(x-s)^{T}A(x-s)}$, where n is the normalisation factor, A is the inverse of the covariance matrix and s is a shift (the mean for multivariate normal distributions). In the article it says $e^{-x^{T}Ax+s^{T}x}$. According to my calculations, experiments and intuition those are not equivalent. For instance, with larger s, the value of the peak becomes larger, while this does not happen with the first definition. Also, if it's only shifted, the integral should not change. So imo, whatever it is, it is not a shifted gaussian. --128.130.118.54 (talk) 10:41, 24 October 2019 (UTC)

Does the opening formula actually work properly?

The opening formula

At the peak, when x=b, everything in the large parenthesis should be 0 ( x-b=0, so (x-b)^2=0, so -((x-b)^2)/(2c^2)=0 ).

This should result in: a EXP 0 = 1.0, regardless of the value of a. But the result should be a, the peak value, by definition of a.

So what part of this am I not understanding? The meaning of EXP? Thanks. — Preceding unsigned comment added by 67.249.?.? (talk) 22:24, 4 February 2015 (UTC)

Ok, I'm reading that EXP usually (but not always) means the constant e (2.718...) raised to a given power. It would probably be a good idea to make this explicit somewhere. Anyway, at the peak this value should still be 1.0 for the reasons given above, but I have to admit my code is working beautifully now!— Preceding unsigned comment added by 67.249.200.163 (talk) 22:23, 4 February 2015 (UTC)

Be more analytical about neural networks

— Preceding unsigned comment added by 2a02:587:4115:3e00:307a:f470:d18b:1cc9 (talk) 01:51, 25 July 2017 (UTC)

Source for Meaning of parameters for the general equation

Can anyone provide the source of the equations listed under Meaning of parameters for the general equation, i.e. coefficients a, b and c? I have calculated them on my own and a couple of signs turned out different. I wonder if there's a textbook that contains the full derivation or the outcome.

KenyaSong (talk) 14:45, 20 July 2018 (UTC)

Wiki Education Foundation-supported course assignment

This article was the subject of a Wiki Education Foundation-supported course assignment, between 25 February 2020 and 8 May 2020. Further details are available on the course page. Student editor(s): NathanielJL.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 22:05, 16 January 2022 (UTC)

Should mention be made that "gaussian" is often not capitalized?

Since the lower-case "gaussian" is pretty common now, I think adding this to the opening sentence is wise.

Spope3 (talk) 06:00, 30 March 2022 (UTC)

History

Why is this called gaussian, since it already appeared in the works of de Moivre ?

I think it would be useful to add some history part saying that this was not invented by Gauss. 2001:861:3008:37D0:34F7:B9ED:A9EB:BEF3 (talk) 20:30, 24 April 2023 (UTC)