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ziofilltoday at 4:20 AM1 replyview on HN

The battery example makes no sense:

capacity_SOH ≈ 0.913 − 0.352 · tanh( cycle^((temperature/cycle)^0.485) )

I understand this fits the data, but exponents should be dimensionless, what is temperature/cycle?


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nyrikkitoday at 5:22 AM

I am not saying this result is correct, but you don't have unit safety in python at all

In this example temperature would be a magnitude, not a unitful value.

At least in the ISO 8000whatever convention where a value is the product of a unit and a magnitude like most people are use to.

Here is a Terry Tao post with more information[0] on why the convention is there, but as he mentions, in differential geometry and Clifford/Geometric Algebra you do things like add vectors to scalers all the time.

[0] https://terrytao.wordpress.com/2012/12/29/a-mathematical-for...

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