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A mathematician's way of converting miles to kilometers

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Re: A mathematician's way of converting miles to kilometers

#61

Post by yyyk »

While using only additions and shifts (if we generalize) without floating point or multiplication should appeal to HN, this method uses a lookup table and calculating values needs a lot of memory accesses e.g. f(7) => f(4) + f(3) => (f(3) + f(5)) >> 2 + f(3) .

The Human Mk1 processing units are also capable of small multiplication/divisions, especially on bases 2 and 10, but bad at lookups - who thought manufacturing units with such slow memory access was a good idea??

I'd rather we play to their strengths and multiply by 1.6 (f(X) = X + X/2 + X/10 for all X) requiring only a few memory accesses. This is already as accurate as the other method. We could make it 1.61 (+ X/100) if we must be more accurate. Any floating point error should be too small to matter.

Re: A mathematician's way of converting miles to kilometers

#65

Post by lonelappde »

bhaak wrote: post #51

The even more useful conversion for me is inch to centimetre: F(n)in ~ F(n+2)cm The Golden Ratio squared is 2.618 which is pretty close to 2.54.

That's also in the thread, posted by Oscar winner and Project Loon developer Dan Piponi, who also has a fantastic technical blog at blog.sigfpe.com

https://mobile.twitter.com/sigfpe/status/1158465136891269121

Re: A mathematician's way of converting miles to kilometers

#66

Post by sergioj97 »

ghaff wrote: post #14
dEnigma wrote: post #10

Fascinating that the second reply (or second best reply?) is an unreasonably angry response: Who the hell needs all this .. Get lost [angry emoji]

There are a fair number of people who seem to take personal offense that the US (and to some degree the UK) don't use SI for everyday types of things and add it to their laundry list of grievances about the US generally. Never mind the fact that SI is generally used for engineering and other areas where it has legitimate advantages (which miles vs. kilometers doesn't really in day-to-day life).

I agree it's not worth the hate, but in my opinion SI units are much more convenient.

Using your own example, miles vs kilometers may not feel like a big difference, but the fact that you have proportional units (mm, cm, m, km) for any possible distance has the potential to save you a lot of trouble. Having completely different units for the same thing (land miles / nautical miles for distance), usually not proportional between them, is less practical than the SI at every level. Not only for an engineer but also for home owners and almost everyone of us.

I understand why there are some places in the world where they still use systems other than the SI, mainly for legacy reasons. But I think the practical benefits of a more coherent (and standard) unit system exist not only for the engineer.

Re: A mathematician's way of converting miles to kilometers

#67

Post by lota-putty »

yyyk wrote: post #61

While using only additions and shifts (if we generalize) without floating point or multiplication should appeal to HN, this method uses a lookup table and calculating values needs a lot of memory accesses e.g. f(7) => f(4) + f(3) => (f(3) + f(5)) >> 2 + f(3) . The Human Mk1 processing units are also capable of small multiplication/divisions, especially on bases 2 and 10, but bad at lookups - who thought manufacturing…

What if we had just 4 digits on each limb or even 6 perhaps.

How does those numbers look in base 8 or 12.

Re: A mathematician's way of converting miles to kilometers

#70

Post by ghaff »

sergioj97 wrote: post #66
ghaff wrote: post #14

Earlier quoted context omitted.

There are a fair number of people who seem to take personal offense that the US (and to some degree the UK) don't use SI for everyday types of things and add it to their laundry list of grievances about the US generally. Never mind the fact that SI is generally used for engineering and other areas where it has legitimate advantages (which miles vs. kilometers doesn't really in day-to-day life).

I agree it's not worth the hate, but in my opinion SI units are much more convenient. Using your own example, miles vs kilometers may not feel like a big difference, but the fact that you have proportional units (mm, cm, m, km) for any possible distance has the potential to save you a lot of trouble. Having completely different units for the same thing (land miles / nautical miles for distance), usually not proportio…

That's fair enough. Whatever the advantages of Imperial in some narrow contexts, I'm not sure very many would argue for them absent legacy.

On the other hand, it's pretty much an academic debate because a switch isn't happening for mainstream use. The desire and political will just aren't there. The little push that once existed is essentially gone whatever some tech types might want.

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