Misc again

[lederhosen]

From madcatapult, a rather amusing Tom Hanks/Harry Potter crossover of sorts. (Spoilers for HBP, if somehow you've managed to avoid them all this time.)

Family outing to dentist yesterday. reynardo was v. brave and all. Having fortunately inherited my father's teeth rather than my mother's (by dint of mammoth legal battle, complicated further by them both still being alive), dental visits are less ouchy for me.

To Melbourne tonight, yay!

Have been playing far too much Evil Genius, a computer game in which you build a Base of Evil on a Volcanic Island of Indeterminate Location and take over the world while fighting off secret agents. Much like a James Bond/Austin Powers version of Dungeon Keeper. It has some irritations (especially pacing - there's a lot of 'sit and wait' time, even *after* I bypassed one chunk of the game with a money cheat), but it's rather fun all the same. The research process is particularly cute - you provide your scientists with the basics (giant laser, centrifuge, greenhouse, etc etc) and then they wander around the base looking at all the *other* items you have for inspiration. Strong incentive to build one of everything. I finally launched my Doomsday Device last night, so I can stop playing :-)

From krfsm, weather porn (work-safe).

Am pleasantly surprised to see that when MATLAB is asked to calculate '1^inf', it returns not '1' but 'NaN', which is the answer of somebody who's as much of a maths geek as me. (Still don't think it should return a value for '0^0', but overall, pretty good.)

Edit: And an amusing beer ad. Which will probably be played to death until it stops being amusing, but it's funnier than the average.

Comments

[madcatapult.livejournal.com]

Er...oops, should have mentioned it was a spoiler. But...please tell me someone who's managed to stay on the internet AND navigate their way around that particular spoiler AND not finished HBP yet...

[lederhosen.livejournal.com]

I got grumbled at yesterday or the day before for linking to a page that contained spoilers... spoilers that had been added to the page *after* I saw it. (Unless they were counting 'OMG Blaise is BLACK!', which I refuse to count as a spoiler...)

[madcatapult.livejournal.com]

BLACK! Nooo, how could they do this to a minor character who never gets any real lines anyway???

Isn't it sad when Rowling has to point out a character is black or asian, because we'll just always assume that if race isn't mentioned, they're austomatically white? I remember her describing Angelina Johnson in the last book as 'a tall black girl' which struck me as odd, because no one is ever 'a short, fat white kid'.

[corruptedjasper.livejournal.com]

Given that the wizarding world -- being about a hundred years out of date and not so much given to relocation and intermarriage as the rest of us -- is almost certainly even whiter than the average pasty-faced Britisher, it's not so strange that the 'default value' is white.

[jesusandrew.livejournal.com]

It's quite possible to do all that and avoid spoilers (although I don't count any more, as I just finished reading HBP an hour ago).

[silmaril.livejournal.com]

Ok, I have to ask for an explanation of the 1^inf=NaN thing.

[lederhosen.livejournal.com]

1^inf is bad in the same way that 0*inf is bad. In fact, if you take the log of (1^inf), that's exactly what you get.

The catch is that although it is often convenient to manipulate 'inf' as if it were a number, it's not. An expression like '1/inf = 0' isn't really saying that inf is the reciprocal of 0; it's more shorthand for 'as x grows arbitrarily large, 1/x tends to 0'. Most instances where inf appears, we're really talking about limits or some such, and all the operations involved are really on *finite* numbers (though possibly an infinite set of all-finite numbers).

There are situations where it's consistent to say that 1^inf = 1, just as sometimes it's consistent to say that 0*inf = 0. (lim_x=>inf0*x certainly equals 0.) But there are others where it breaks down; in the neighbourhood of x=1, y = inf, the function z=x^y is horrendously discontinuous.