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Monday, October 1, 2007

Happy October

October is usually a good month. It took its time arriving, this year.

To celebrate the first day of October I spent four hours on assignment 9, which is now seven-eighths complete. Visited Peter once during the morning and subsequently discovered why DEs are so horrible [the vast majority of them aren't soluble at all, and even more are insoluble by our current methods].

Battling Rugby World Cup syndrome I then went to a lecture, which seemed to be very strongly grounded in physical reality. It's years now since I chose not to study physics, and since then I've additionally realised that the real world is just not interesting. If DEs are no good for anything except describing reality, they become boring as well as horrible. I must investigate this further.


gliderguider said...

Oh! You didn't know that most DEs are solvable only by numerical methods!!!

There really are some amazingly efficient and accurate numerical methods for them these days, at least for smooth and nicely behaved DEs.

I even used some of them about .. er .. right years ago I think, when a friend who was in a startup rocket plane company wanted to know what the most efficient flight path and engine power strategy was for using a rocket powered spaceplane to go from one point to another on the earth. Turns out you get quite different answers depending on whether you want to maximize range, minimize time, minimize fuel use, maximize cargo load, or whatever.

The nastiest problem turns out to be maximizing profit on a scheduled service -- sometimes it's worth going inefficiently fast because that lets you get in one more flight a day, or operate with one fewer vehicle.

Gael said...

Gah! The real world strikes again!

gliderguider said...

Nasty reality, cruel reality, dirty reality. Gone and left us, gaelum, and precious pure equations are soiled with nasty numbers. Math tricked us! Thieved our precious!

btw, here's something on a similar kind of topic:

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