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Kyle Kanos

1:55 AM

Holy crapola!

Simulation went from finishing in ~3 hours to finishing in under 2 be changing those two lines

How the hell did the original developers not see that!?

dmckee

@KyleKanos Well, there are always so many lines...

How much of a speed up did you get in the guilty routine?

Kyle Kanos

Well, 60k lines....but you'd figured they'd have, at some point at least, do a timing analysis

Went from being 10 ks to 400 s, so roughly 25. But some of that was absorbed into another routine that I don't know the numbers for

dmckee

Nice.

I've gotten that scale of improvement once or twice, but never in just a couple of lines.

I had to add a whole R*-tree implementation.

Kyle Kanos

Lol. It's now saying it spent 0.07s on each of those two lines for the whole simulation

@dmckee For analyzing beam data?

dmckee

@KyleKanos Clustering hits in a TPC. The original code was O(n^2) and thrown together for a prototype device that rarely had more that 1500 hits. Then we tried to apply it to simulated data for a fullscale machine with as many as 30,000 hits...

DBScan solved it, but it needs a R*-tree.

Kyle Kanos

2:10 AM

Ouch

9 hours later…

Physics Meta

10:51 AM

Q: Precise directives re flagging

I stopped editing because it makes posts bump on the front page, but I am still trying to do my whack to improve the site. I'd like to know what is the exact policy regarding flags, please answer with a clear Yes/No to each question: 1) "avoid comments like '+1' or 'thanks' ", is this just a r...

discussion

Danu

11:19 AM

@KyleKanos really funny, guys!

@Waffle'sCrazyPeanut ping pang pong

@ACuriousMind Shut it, you! Making me feel bad

@Jim Portal was great, but also quite short.

@ManishEarth Were we really? Are you refering to the whole Ron Maimon situation?

3 hours later…

ManishEarth

2:47 PM

@Danu Yep

Amongst the larger network community (Meta, the mods, etc) who are aware of network wide issues, we were known for it

Not exactly that single situation though. There have been more incidents.

Danu

3:35 PM

@ManishEarth Physics, so rowdy

4 hours later…

Physics Meta

7:59 PM

Q: How do you guys feel about minor edits?

I recently saw a post (a question) where the edits made were as follows (no link, do not want to single out): Edit 2 (suggested, approved) was numerous but minor grammar / capitalization fixes; the question was already readable prior. Edit 3 (privileged) added a missing space between two words ...

discussion editing

tpg2114

8:14 PM

@KyleKanos I'll let the 14 point spread slide... I don't think anybody in the world would have expected our defense to finally show up in a game.

Too bad VT doesn't seem to want to help us win the conference

Duke is trying hard to blow it though

JamalS

8:31 PM

@Danu Good evening :)

Danu

8:47 PM

@JamalS hi there

CoilKid

Hello, I don't suppose any of you know the energy release from burning sugar?

Danu

this must be easy to find online, somewhere ;)

CoilKid

I know, right? I've looked but either I don't know where to look, or what to look for..

I need the energy released so calculate how hot my combustion chamber will get (I want to make a simple sugar rocket)

Danu

9:02 PM

lol, that sounds pretty fun

JamalS

@CoilKid: Well, there are 15.9 J stored in 1 gram of sugar.

CoilKid

I asked on chem.se but no reply yet

2 hours later…

Physics Meta

10:36 PM

Q: When is a thought experiment not a physics question?

The question Is a Thomson's lamp physically realistic? has been put on hold for being off topic. I am not clear why that is the case. I understand that the question is philosophically motivated but I think it is suitable for physical considerations. I think one can answer the question in a no...