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<p>我试图编写一个Python函数,它返回与NetHack游戏中相同的月相值。这可以在<a href="http://nethack.wikia.com/wiki/Source:Hacklib.c#phase_of_the_moon" rel="nofollow noreferrer">hacklib.c</a>中找到。在</p>
<p>我试图简单地从NetHack代码中复制相应的函数,但我不相信我得到了正确的结果。在</p>
<p>我写的函数是<code>phase_of_the_moon()</code>。在</p>
<p>我在网上找到的函数<code>position()</code>和{<cd3>},我用它们来表示我的功能是否成功。它们非常精确,给出的结果与nethack.alt.org服务器(请参见<a href="http://alt.org/nethack/moon/pom.txt" rel="nofollow noreferrer">http://alt.org/nethack/moon/pom.txt</a>)。然而,我所追求的是对原始NetHack功能的精确复制,特性完好无损。在</p>
<p>我希望我的函数和“控制”函数至少能给出相同的月相,但目前它们没有,我也不知道为什么!在</p>
<p>以下是NetHack代码:</p>
<pre><code>/*
* moon period = 29.53058 days ~= 30, year = 365.2422 days
* days moon phase advances on first day of year compared to preceding year
* = 365.2422 - 12*29.53058 ~= 11
* years in Metonic cycle (time until same phases fall on the same days of
* the month) = 18.6 ~= 19
* moon phase on first day of year (epact) ~= (11*(year%19) + 29) % 30
* (29 as initial condition)
* current phase in days = first day phase + days elapsed in year
* 6 moons ~= 177 days
* 177 ~= 8 reported phases * 22
* + 11/22 for rounding
*/
int
phase_of_the_moon() /* 0-7, with 0: new, 4: full */
{
register struct tm *lt = getlt();
register int epact, diy, goldn;
diy = lt->tm_yday;
goldn = (lt->tm_year % 19) + 1;
epact = (11 * goldn + 18) % 30;
if ((epact == 25 && goldn > 11) || epact == 24)
epact++;
return( (((((diy + epact) * 6) + 11) % 177) / 22) & 7 );
}
</code></pre>
<p>下面是<code>getlt()</code>函数(也在hacklib.c中):</p>
^{pr2}$
<p>下面是我的Python代码:</p>
<pre><code>from datetime import date
def phase_of_the_moon():
lt = date.today()
diy = (lt - date(lt.year, 1, 1)).days
goldn = ((lt.year - 1900) % 19) + 1
epact = (11 * goldn + 18) % 30;
if ((epact == 25 and goldn > 11) or epact == 24):
epact += 1
return ( (((((diy + epact) * 6) + 11) % 177) / 22) & 7 )
import math, decimal, datetime
dec = decimal.Decimal
def position(now=None):
if now is None:
now = datetime.datetime.now()
diff = now - datetime.datetime(2001, 1, 1)
days = dec(diff.days) + (dec(diff.seconds) / dec(86400))
lunations = dec("0.20439731") + (days * dec("0.03386319269"))
return lunations % dec(1)
def phase(pos):
index = (pos * dec(8)) + dec("0.5")
index = math.floor(index)
return {
0: "New Moon",
1: "Waxing Crescent",
2: "First Quarter",
3: "Waxing Gibbous",
4: "Full Moon",
5: "Waning Gibbous",
6: "Last Quarter",
7: "Waning Crescent"
}[int(index) & 7]
def phase2(pos):
return {
0: "New Moon",
1: "Waxing Crescent",
2: "First Quarter",
3: "Waxing Gibbous",
4: "Full Moon",
5: "Waning Gibbous",
6: "Last Quarter",
7: "Waning Crescent"
}[int(pos)]
def main():
## Correct output
pos = position()
phasename = phase(pos)
roundedpos = round(float(pos), 3)
print "%s (%s)" % (phasename, roundedpos)
## My output
print "%s (%s)" % (phase2(phase_of_the_moon()), phase_of_the_moon())
if __name__=="__main__":
main()
</code></pre>