Rocksolid Light

Welcome to Rocksolid Light

mail  files  register  newsreader  groups  login

Message-ID:  

The two most common things in the Universe are hydrogen and stupidity. -- Harlan Ellison

interests / rec.games.roguelike.nethack / Definition of moon phases (start date of NH full moon)

SubjectAuthor
* Definition of moon phases (start date of NH full moon)Janis Papanagnou
`* Definition of moon phases (start date of NH full moon)Pat Rankin
 `- Definition of moon phases (start date of NH full moon)Janis Papanagnou

1
Definition of moon phases (start date of NH full moon)

<tkbf0f$3kne4$1@dont-email.me>

  copy mid

https://news.novabbs.org/interests/article-flat.php?id=2810&group=rec.games.roguelike.nethack#2810

  copy link   Newsgroups: rec.games.roguelike.nethack
Path: i2pn2.org!i2pn.org!aioe.org!eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: janis_papanagnou+ng@hotmail.com (Janis Papanagnou)
Newsgroups: rec.games.roguelike.nethack
Subject: Definition of moon phases (start date of NH full moon)
Date: Mon, 7 Nov 2022 18:24:31 +0100
Organization: A noiseless patient Spider
Lines: 20
Message-ID: <tkbf0f$3kne4$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Injection-Date: Mon, 7 Nov 2022 17:24:31 -0000 (UTC)
Injection-Info: reader01.eternal-september.org; posting-host="593c6f9a62a017d87821e7d42510d1ed";
logging-data="3825092"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/iNb/E3HYr1ZuWcJg6cGwL"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
Thunderbird/45.8.0
Cancel-Lock: sha1:Wz8loqd2O16XiiGjpkGsuW4CyqE=
X-Enigmail-Draft-Status: N1110
X-Mozilla-News-Host: news://news.eternal-september.org:119
 by: Janis Papanagnou - Mon, 7 Nov 2022 17:24 UTC

In Nethack the moon phases are quantified in eight phases, each
phase covering three or four days.

These days real full moon is around Tuesday, 2022-11-08, 12:00.
Having (in Nethack) a period of three days for full moon now my
expectation would be that the Nethack phase would start one day
before real full moon and end one day after real full moon.

(Note: I'm in a central EU time zone but the question is still
valid if we assume, say, UTC+6 or UTC-6.)

If I start NH-343 or Slashem now I don't get the "You're lucky"
full moon message.

Is Nethack's three-days lasting full moon _starting_ at real
full moon (and ending three day after real full moon), or am I
missing something?

Janis

Re: Definition of moon phases (start date of NH full moon)

<82879450-f810-42e3-91b9-967efe1d6557n@googlegroups.com>

  copy mid

https://news.novabbs.org/interests/article-flat.php?id=2811&group=rec.games.roguelike.nethack#2811

  copy link   Newsgroups: rec.games.roguelike.nethack
X-Received: by 2002:ae9:d806:0:b0:6f1:15cc:d870 with SMTP id u6-20020ae9d806000000b006f115ccd870mr40438235qkf.114.1667936259897;
Tue, 08 Nov 2022 11:37:39 -0800 (PST)
X-Received: by 2002:a05:6808:1247:b0:353:4258:718f with SMTP id
o7-20020a056808124700b003534258718fmr30842889oiv.155.1667936259631; Tue, 08
Nov 2022 11:37:39 -0800 (PST)
Path: i2pn2.org!i2pn.org!usenet.blueworldhosting.com!feed1.usenet.blueworldhosting.com!peer01.iad!feed-me.highwinds-media.com!news.highwinds-media.com!news-out.google.com!nntp.google.com!postnews.google.com!google-groups.googlegroups.com!not-for-mail
Newsgroups: rec.games.roguelike.nethack
Date: Tue, 8 Nov 2022 11:37:39 -0800 (PST)
In-Reply-To: <tkbf0f$3kne4$1@dont-email.me>
Injection-Info: google-groups.googlegroups.com; posting-host=75.51.81.46; posting-account=PWiXPAoAAABrA15ZgKdYDhP2ItsYPeoJ
NNTP-Posting-Host: 75.51.81.46
References: <tkbf0f$3kne4$1@dont-email.me>
User-Agent: G2/1.0
MIME-Version: 1.0
Message-ID: <82879450-f810-42e3-91b9-967efe1d6557n@googlegroups.com>
Subject: Re: Definition of moon phases (start date of NH full moon)
From: r.pat.rankin@gmail.com (Pat Rankin)
Injection-Date: Tue, 08 Nov 2022 19:37:39 +0000
Content-Type: text/plain; charset="UTF-8"
X-Received-Bytes: 1748
 by: Pat Rankin - Tue, 8 Nov 2022 19:37 UTC

On Monday, November 7, 2022 at 9:24:35 AM UTC-8, Janis Papanagnou wrote:
> Is Nethack's three-days lasting full moon _starting_ at real
> full moon (and ending three day after real full moon), or am I
> missing something?

The relevant code is phase_of_the_moon() in hacklib.c.
Good luck making any sense out of it. I can't claim that
I comprehend it (aside from the pointless optimization
of '(X) & 7' instead of '(X) % 8' as the final step to yield
0..7 for the eight divisions of the month).

It uses integer arithmetic, making it more complicated
and conceivably introducing drift cause by accumulated
round-off error.

Re: Definition of moon phases (start date of NH full moon)

<tkeggl$ctg$1@dont-email.me>

  copy mid

https://news.novabbs.org/interests/article-flat.php?id=2812&group=rec.games.roguelike.nethack#2812

  copy link   Newsgroups: rec.games.roguelike.nethack
Path: i2pn2.org!i2pn.org!aioe.org!eternal-september.org!reader01.eternal-september.org!.POSTED!not-for-mail
From: janis_papanagnou+ng@hotmail.com (Janis Papanagnou)
Newsgroups: rec.games.roguelike.nethack
Subject: Re: Definition of moon phases (start date of NH full moon)
Date: Tue, 8 Nov 2022 22:08:36 +0100
Organization: A noiseless patient Spider
Lines: 43
Message-ID: <tkeggl$ctg$1@dont-email.me>
References: <tkbf0f$3kne4$1@dont-email.me>
<82879450-f810-42e3-91b9-967efe1d6557n@googlegroups.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Injection-Date: Tue, 8 Nov 2022 21:08:37 -0000 (UTC)
Injection-Info: reader01.eternal-september.org; posting-host="00ccd77240f132e4816291cff99f62a2";
logging-data="13232"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/H7ZUEJEJEGcAnd6ZERZwW"
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
Thunderbird/45.8.0
Cancel-Lock: sha1:r9ICKGgKIUrECCSqRbjFP9E3wpo=
In-Reply-To: <82879450-f810-42e3-91b9-967efe1d6557n@googlegroups.com>
X-Enigmail-Draft-Status: N1110
 by: Janis Papanagnou - Tue, 8 Nov 2022 21:08 UTC

On 08.11.2022 20:37, Pat Rankin wrote:
> On Monday, November 7, 2022 at 9:24:35 AM UTC-8, Janis Papanagnou wrote:
>> Is Nethack's three-days lasting full moon _starting_ at real
>> full moon (and ending three day after real full moon), or am I
>> missing something?
>
> The relevant code is phase_of_the_moon() in hacklib.c.
> Good luck making any sense out of it.

I already inspected that code some years ago. _Analytically_
I also cannot derive anything from that formula.

I had also used a Javascript transcription of that formula
for http://random.gridbug.de/moonphase.html and added a "-1"
correction factor for "Nethack mode" (a click on the header
text toggles modes).

_Empirically_ I did notice last midnight that Nethack claims
new moon _today_. So it *seems* that the day when new moon
is defined in Real Life will start Nethack's new moon phase.

> I can't claim that
> I comprehend it (aside from the pointless optimization
> of '(X) & 7' instead of '(X) % 8' as the final step to yield
> 0..7 for the eight divisions of the month).

I wouldn't even consider that an optimization; it was, maybe,
5 decades ago. :-)

>
> It uses integer arithmetic, making it more complicated
> and conceivably introducing drift cause by accumulated
> round-off error.

I assumed the formula to be correct and was just wondering
about the placement of the 3-4 days interval around the Real
Life new moon.

I also cannot tell anything about wobbling drifts (if any)
or other drifts.

Janis

1
server_pubkey.txt

rocksolid light 0.9.81
clearnet tor