Harry Potter and the Methods of Rationality discussion thread, part 15, chapter 84

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The next discussion thread is here.

This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 84. The previous thread has passed 500 comments. Comment in the 14th thread until you read chapter 84.

There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)

The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14.

As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.

Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically:

You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).

If there is evidence for X in MOR and/or canon then it’s fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that “Eliezer said X is true” unless you use rot13.

The next discussion thread is here.

As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.

Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically:

You do not need to rot13 anything about HP:MoR or the original Harry Potter series unless you are posting insider information from Eliezer Yudkowsky which is not supposed to be publicly available (which includes public statements by Eliezer that have been retracted).

If there is evidence for X in MOR and/or canon then it’s fine to post about X without rot13, even if you also have heard privately from Eliezer that X is true. But you should not post that “Eliezer said X is true” unless you use rot13.

This is quite Quirrellicious:

signal = []
t=0
for (p,d) in [(4,1),(5,1),(7,3),(None,1), (4,1),(5,1),(7,3),(None,1), (4,1),(7,1),(12,2),(11,2),(9,2),(9,2),(7,1),(None,1), (2,1),(4,1),(5,3),(None,1), (2,1),(4,1),(5,3),(None,1), (2,1),(5,1),(11,1),(9,1),(7,2),(11,2),(12,4)]:
    if p is not None: add_note(t, 440*2**(((p+random.choice([-1,0,0,0,1]))+random.random())/12.), 0.3*d+0.1, 1)
    t += 0.3*d*math.exp(random.random()*random.random())
save_signal()

It (1) displaces 20% of notes up and 20% of notes down by one semitone, (2) detunes all notes randomly by about +/- a quarter-tone, and (3) inserts random delays, usually quite short but up to a factor of about 1.7 times the length of the preceding note or rest.

[EDITED to add: actually, I think it distorts the pitches just a little too much.]

[FURTHER EDITED: really, it should be tweaked so that when two consecutive notes in the original melody are, say, increasing in pitch, the same is true of the distorted ones. I am too lazy to make this happen. A simpler improvement is to replace the two pitch-diddlings with a single call to random.choice() so that you never get, e.g., a semitone displacement plus a quarter-tone mistuning in the same direction. I also tried making the timbre nastier by putting the partials at non-harmonic frequencies, which does indeed sound quite nasty but not in a particularly hummable way. This doesn't introduce as much nastiness as it would in music with actual harmony in it; one can make even a perfect fifth sound hideously discordant by messing up the spectrum of the notes. See William Sethares's excellent book "Tuning, timbre, spectrum, scale" for more details, though he inexplicably gives more attention to making music sound better rather than worse.]