gaussian function in maths/gaussian.py seems wrong

[kunl7564]

1 / sqrt(2 * pi * sigma ** 2) * exp(-(x - mu) ** 2 / 2 * sigma ** 2)

should be

1 / sqrt(2 * pi * sigma ** 2) * exp(-(x - mu) ** 2 /( 2 * sigma ** 2))

[BenSandeen]

According to Wikipedia https://en.wikipedia.org/wiki/Gaussian_function, the current representation looks correct to me. I think it would make sense to pull both of the ** 2 out of the exponential and just put them outside the parentheses, like this:

1 / sqrt(2 * pi * sigma ** 2) * exp(-1 / 2 * ((x - mu) / sigma) ** 2)

[kunl7564]

1 / sqrt(2 * pi * sigma ** 2) * exp(-(x - mu) ** 2 / 2 * sigma ** 2) equals
1 / sqrt(2 * pi * sigma ** 2) * exp(-(x - mu) ** 2 * sigma ** 2 / 2) which is not correct to me
but not
1 / sqrt(2 * pi * sigma ** 2) * exp(-(x - mu) ** 2 / 2 / sigma ** 2) which is correct to me

[cclauss]

Could you please write a doctest for the failing usecase? Please read CONTRIBUTING.md for details.

[kunl7564]

I notice that this issue has already been fixed in f6bd8c9

Not sure if there is still something I can help.

[darkmatter18]

Hi, @kunl7564 I tested the algorithm for both

1. 1 / sqrt(2 * pi * sigma ** 2) * exp(-(x - mu) ** 2 / 2 * sigma ** 2)
   2 . 1 / sqrt(2 * pi * sigma ** 2) * exp(-(x - mu) ** 2 /( 2 * sigma ** 2))

Both seem to produce the same output. I think the issue is not actually an issue.

[cclauss]

Already been fixed in f6bd8c9