Watched 21 last night – not a bad film, in fact, regarding entertainment vs. cost value [it ran us just £3 from Matalan!] it was rather good.
The film is based upon the MIT Blackjack team, and as I’ve read/and-seen quite a lot about them before, I was quite happy to have the film thicken the plot [maybe that should be 'have one'?] – and there’s a nice twist or two at the end. As to the film’s inspiration, you can’t do much better than watch the BBC Horizon documentary on this:
Making Millions the Easy Way
I wish ‘Oxford types’ would get up to stuff like this [of course, they might do (would they tell their lecturers?)]; it’d be so much more fun!
Probability
I was quite pleased to see some probability stuff in the film being partially explained, i.e., their running through the Monty Hall problem [although the implied cleverness of the student here is a bit hard to swallow really].
Anyway, here’s the problem:
Suppose you’re on a game show, and you’re given the choice of three doors: Behind one door is a car; behind the other two, goats. You pick a door, say number 1, and the host, who knows what’s behind all of the doors, always opens another door – to reveal a goat – let’s say that’s door number 3. He then says to you, “Do you want to swap?”, i.e., swap your initial choice of door number 1, and change to door number 2? The crux being – is it to your advantage to swap?
In the film, the problem is presented in this clip. By the way, the answer is in this too, so if you want to think about it, get ready to hit the pause button at the 44s mark!
The explanation I find that works quite well here [and I've had my Oxford stats students scratching their heads over this problem initially (as do most people I believe)] is:
Given this scenario: when you pick a door, you’re more likely to pick a goat-door than sole car-door, i.e., you’ve a probability of .66 [or 66% chance if you prefer] of picking one of the two goat-doors vs. the only car-door. Hopefully, that’s obvious.
So, if chance [substitute luck of the draw/fate/the odds/divine-intervention ...] did the right thing here, and you picked a goat-door, you know with a decent probability that the car is behind one of the two remaining doors – but which one? Now, when the host reveals another goat behind one of the two remaining doors, the car’s obviously [again, if the odds etc worked for your initial pick] behind the other door!
Basically, it comes down to this: if you picked a goat-door initially [which you will 66% of the time], by swapping later, you’ll always win the car. Conversely, and given once again that you initially picked a goat-door, if you don’t swap, you’ll lose 66% of the time. Or, one other way … by swapping, you’ll only lose if you picked the sole car-door as your first pick [which you're likely not to have done].
Update: Just found a nice little simulator of this [Internet Explorer only] at http://www.grand-illusions.com/simulator/montysim.htm
Update: I’ve written a small simulator of the problem here (zipped .exe)
I learned yesterday about David Foster Wallace‘s [apparent] suicide.
There’s also the strange coincidence though – last night, I needed a new book, so I turned to my ‘to be read’ pile and at the top was ‘everything and more: a compact history of infinity‘. It wasn’t until I was about to put it down, and spotted that the author had also written ‘Infinite Jest‘ that it hit me.
It’s on another page on peetm.com, but as I’ve been asked where it was lately, I’ll just link to it here.
One of the cool things about being at a university [still] is that people discard rubbish that’s someone else’s ‘treat’.
Recently I found a ‘Programming Languages’ Volume 2 manual for the PDP-8 – and it’s become my essential bedtime reading for now.
The book’s full of great stuff about how you should ensure that you’ve a teletype attached, and that you’ve got the steam-pressure just right before turning the thing on in the first place!
It takes me back to a time when programmers were, um, ‘novel’, men were ‘chaps’ and girls wore petticoats [actually, I got a bit carried away there!]
On languages, the book talks mostly about Focal; which I’d forgotten about altogether [a blessing really], here’s the Focal code for the Towers of Hanoi …
I loved the PDP-8 though – keying in the bootstrap and forgetting to load the punched-tape was a great way to spend a half hour or so [oh, how I WOULD LAUGH at times like those!]
If you fancy playing with a real PDP-8[E] albeit remotely, then have a look here [you can even watch the machine operate via a webcam]: http://www.pdp8online.com/run.shtml
Went to see Brian Clegg give a talk on Infinity – based on his book, hosted by Cafe Scientifique, and sponsored by Blackwell’s bookshop.
After hearing Brian, I don’t feel so bad about often misspelling his name as ‘Brain’ – Brain Clegg sounds about right!
I also felt rather envious: how rewarding it must be; being able to research a subject one feels so taken by, have it published, and then enjoy speaking on it once in a while!
In the picture above Brian is about to get a bit heavy for some of the audience [judging by the majority of the questions asked in the Q&A]. He’s previously gone from potential-infinities [
] and just got to Cantor‘s countable (concrete) infinites [
], and is moving into the rather beautiful proof that there are still larger ones (sans having Brian around for tea, here’s a nice walk-through for anyone interested).
I love this – which I saw in Eats Shoots and Leaves:
Peet: I want a man who knows what love is all about. You are generous, kind, thoughtful. People who are not like you admit to being useless and inferior. You have ruined me for other men. I yearn for you. I have no feelings whatsoever when we’re apart. I can be forever happy–will you let me be yours? Jo
And again with different punctuation:
Peet: I want a man who knows what love is. All about you are generous, kind, thoughtful people, who are not like you. Admit to being useless and inferior. You have ruined me. For other men, I yearn. For you, I have no feelings whatsoever. When we’re apart, I can be forever happy. Will you let me be? Yours, Jo
Brian Clegg's recent post on Book Covers reminded me of what I consider to be the worst book cover in my collection:
What do you think? It's a book on Windows Programming, yet features a guy who looks bored [and wearing a suit!] and looking out a window. Then there's the old PC in the foreground – running some DOS application!
If people were put off by the cover, it's a shame really – this book has one of the very best descriptions of Windows' Mapping Modes I've ever seen – the best in fact.
I replied, "Um, yes I do, but I don't have that one!"
What they'd handed me was a
1st edition and first printing – from 1979, and they were going to donate this to one of our libraries at Oxford.
Well, what could I do – I offered to swap my Penguin Books paperback edition from 1980 – to which they agreed.
And now I'm a very happy man. Not only because I love this book and now love owning a 1st edition, but because, upon browsing through it once again, I re-discovered a few of the joys nestled in its pages, for example, the chapter on Propositional Calculus. I now intend to re-read the whole thing once again.
Today, things just haven't gone right – much.
I still have a cold – and its got heavier – and drove me to have to go back to bed this pm. "I'll nap for a few mins", which turned into about four hours. So, that's a chunk of the day missed. I was also due to go to a wine tasting this evening – but having the snots make that socially unacceptable.
My 3Com 1100 switch is refusing to 'play ball' – but, what with my cold I'm not so inclined to investigate the why in detail today. I also think my ISP was playing silly buggers as I was tweaking it – which didn't help the head scratching. Still the Silenx fan I installed in it works a treat … so much so that I thought at first that it was duff – yes, it's that quiet that I had to see it spinning to know it was working!
I missed my son a lot. Sometimes I think school is cruel – not from his point of view [on one of his non-moaning mornings] – but from mine. As I work more or less totally from home these days, it seems that when I've returned from walking him in, that *my* life is cruelly affected. It's funny how just hearing your child patter around the place can light up your heart. He used to be Home Educated, and while that largely failed on a number of fronts for us, I do sometimes wish it were still the case – although I'd have only sneezed all over him lately and made him ill I suppose!
Just heard from a ex-Oxford friend and office mate of mine who's in Princeton: a lady who it was impossible not to soak up a smile from in any given day one was fortunate enough to be in her presence – even if it were but 'fleeting'. Jana, I miss you – come back! OR – at least get on Facebook!
Brian Clegg pisses me off 
I just read some of his stuff: his review of a novel, and then his blog. I hate [too strong] people who can write — I mean my 'reviews' are usually one liners, or even one word-ers ["crap", "Get it and read it", ...]. Yes, I'm sure I could do better, but I'd never be able to do 'a Clegg'. Brian doesn't really piss me off of course – I'm just jealous!
One good thing from today – I now know what Spirax Sarco 'do'. I've seen this company's buildings for about 20 years, and walk by their head office when I'm walking Daniel to school – but, until today – although I've often asked myself – I've not known what they actually produce. Many years ago someone told me it was zippers, and maybe that's why it's always slipped my mind to 'go see' myself. Anyway, today I finally remembered: it's stuff to do with boilers and steam heating. Must say that I preferred thinking it was zips.
P.S. In the bit about Brian there are two hyper-links. Do they appear the same to you – colour etc? One of them is yellow/orange for me, whilst the other is a light blue. I wish I could figure out the difference my style-sheet makes of these. I would investigate but well, you know – atchoo!
