On Mon, Jan 10, 2022 at 8:20 PM Raul Miller wrote:
> Hmm...
>
> I like your use of reference rotations R. And, your approach to
> combining what were a bunch of different steps in mine looks nice. (It
> takes a bit longer this way, but for this puzzle the extra time I
> needed to code up my appro
Ah, I somehow had overlooked that part of the puzzle.
Thanks,
--
Raul
On Mon, Jan 10, 2022 at 6:29 PM 'Mike Day' via Programming
wrote:
>
> Perhaps we’re not talking about the same thing. I was using this bit of the
> problem description:
> “By finding pairs of scanners that both see at leas
Perhaps we’re not talking about the same thing. I was using this bit of the
problem description:
“By finding pairs of scanners that both see at least 12 of the same beacons,
you can assemble the entire map”
So for each scanner I found its inter-beacon distances, which are independent
of th
On Mon, Jan 10, 2022 at 1:17 PM 'Michael Day' via Programming
wrote:
> You mentioned looking for 67 or 68 of the same beacon distances. My
> criterion was >: 66, iirc, since 12 matching distinct points would have
> 66 = 11.12%2 pairs of non-zero distances.
Actually, I was looking for at least
Hmm...
I like your use of reference rotations R. And, your approach to
combining what were a bunch of different steps in mine looks nice. (It
takes a bit longer this way, but for this puzzle the extra time I
needed to code up my approach is far more of a problem.)
But how did you come up with 12
Thanks for this and for the previously undefined "cross" in another post.
I now see why I got 48 rotations rather than 24 - I hadn't taken on board
that all scanners used the "same" coord system, which others have
interpreted
as all using the same parity.
You mentioned looking for 67 or 68 of
Main insight here was that with any beacon being scanned from scanners 0
and s it holds that b₀ = Tₛ + bₛ*Rₛ with b₀, bₛ being the beacons
coordinates relative to 0, s resp., Tₛ is s' translation vector and Rₛ the
cube rotation matrix belonging to s.
This means Tₛ = b₀ - bₛ*Rₛ and we can calculat
Well, I was using my right hand/ lh/ 2 fingers & thumb, a la Faraday, for
insight!
Didn’t help!
Mike
Sent from my iPad
> On 10 Jan 2022, at 04:54, Raul Miller wrote:
>
> I should perhaps clarify -- since there's no actual physical
> coordinates involved here. I am using "left handed" and "ri
Sure. Sorry, excuse my phrasing; that’s what I meant but didn’t express
clearly!
Ciao,
Mike
Sent from my iPad
> On 10 Jan 2022, at 03:21, Pierpaolo Bernardi wrote:
>
>> Il giorno 9 gennaio 2022, alle ore 20:56, 'Michael Day' via Programming
>> ha scritto:
>>
>> Chat really, but I think
I should perhaps clarify -- since there's no actual physical
coordinates involved here. I am using "left handed" and "right handed"
to refer to what should maybe be labeled as the parity of the axes of
the coordinate system.
I really need better vocabulary for talking about these distinctions.
Th
Also, ... I believe that that cross product is a right handed cross
product. It would be interesting to think about what would need to
change to make a left handed cross product work (for example, the
cross product implementation in the complete tensor essay in the
wiki).
(I had thought that I was
Il giorno 9 gennaio 2022, alle ore 20:56, 'Michael Day' via Programming
ha scritto:
>Chat really, but I think it still belongs here.
>I've just had another look at the performance stats for day 19. The numbers
>solving parts 1 & 2 are 15420 and 236, respectively., at the time of
>typing.
>Weir
Oops, I thought I had included that in my message. My apologies:
NB. from https://code.jsoftware.com/wiki/Phrases/Matrices
cross=:(1 _1 1 * 1 (-/ . *)\. ])@,.
Good question, thanks.
--
Raul
On Sun, Jan 9, 2022 at 9:49 AM 'Michael Day' via Programming
wrote:
>
> Raul, would you mind defining
Chat really, but I think it still belongs here.
I've just had another look at the performance stats for day 19. The numbers
solving parts 1 & 2 are 15420 and 236, respectively., at the time of
typing.
Weird - once you've done part 1, there's hardly anything further to do
in part 2 !
Perhaps
Raul, would you mind defining cross? I've tried */ and (+/ . *) but
neither seem to
work for me, and I'm not sure what you mean.
As I said a few days ago, I gave up wondering why I'd found 48
rotations when they
asked for 24, couldn't grasp what the meant by facing" and resorted to
matr
Here's a better 'relori', in my opinion:
NB. y: scans from two scanners
relori=: {{
sigs=: signature each y
upsigs=: 0-.~(~. #~ 2 = #/.~) ;~.@,each sigs
masks=: (* wrote:
>
> https://adventofcode.com/2021/day/19
>
> Like a variety of my work on previous days, my code here is rather
> bulky.
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