The red points are the grid points just inside the plasma, and the blue points are the interpolated position of the last closed flux surface. This would have been a simple problem, except the Python NURBS library doesn't work and hasn't been updated in years. This wasn't an actual wheel re-inventing event, but I did find that all current wheel implementations were but shattered monuments, and was forced to chisel my own by studying the shards I was able to excavate from the hardening loam of the Internet's sedimentary layers.
Once the grid is represented as a non-uniform rational B-spline (which just sounds cooler than "NURBS"), finding the plasma boundary is just an exercise in projecting the surface onto a plane and finding roots of some cubic equations. So, after spending a few hours mixing up the array indexes, I managed to write a beautiful solution to my problem. Most importantly, it got rid of the nasty wedges of points where the psi-solver would generate bad data.
The only issue left on my list of bugs is that the boundary finder will get confused if there are any regions of vacuum flux that exceed zero flux. That tends to happen near vertical field coils, especially when computing equilibria for highly shaped plasmas. Unfortunately, plasma shaping is very important, so I'll probably have to fix this eventually. For this paper, though, I'm going to stick to circular, large aspect ratio equilibria. Nothing too exotic.
I don't speak a word of Arabic, but if someone will tell me how to write, "If this T-Shirt is all it takes to make you worry, then you are a racist asshole," I will put it on a T-Shirt and wear it whenever I fly.
I think science is afflicted by a naming-mania. Maybe this is a side effect of biology envy. Biology has names for millions of things; millions of species, hundreds (or maybe thousands) of organs, millions of molecules, and maybe tens of millions of processes. Astronomy, on the other hand, really only has a few clearly distinct objects; rocks, blobs of (somewhat) ionized gas, stars, star corpses, big blobs of stars, big blobs of blobs of stars, and Other. Which particular rocks we call "planets" is an essentially arbitrary choice. At parties, biologists pontificate at length about the peptide sequence of Glycine reuptake receptors they found in the presynaptic ganglia located in the deutocerebrum of the latest and most fashionable breed of knock-out Drosophila melanogaster, and astronomers are forced to string together ordinary words to describe how gas falls onto the surface of a white dwarf. Maybe they feel inadequate that their jargon isn't rich enough, and so they are racing to catch up with biology. Someone ought to slap some sense into them.
Let us meditate on this problem for a moment. Right now, the Moon is a moon. However, it is slowly drifting away from Earth, and will someday escape and begin orbiting the Sun. Then it will "become" a planet. Or, by the time it happens, astronomers would classify it as an under-sub-sub-mini-sub-micro-dwarf planet. But it didn't really "become" anything. It just followed a trajectory. So why change the name? It would really be much neater, and more honest, to adopt a naming convention that recognizes that when we name things that lie on a continuous scale, we make essentially arbitrary demarcations. Take a group of objects that includes rocky things the size of my left upper molar, the size of Manhattan, the size of Madagascar, and the size of Mars. Which things we call "planets" and which things we call "debris" is simply a matter carving up the universe into bins that are convenient for our little anthrocentric minds.
I think someone ought to sue for an injunction against the use of the term "dwarf planet" until an investigation has been conducted to determine how much money the members of the International Astronomical Union will make from the new editions of fifth-grade science textbooks that will surely be required if this change is permitted.
They should fire whoever is in charge of the reconstruction, divide the city into small zones, and put each one under the management of locals like Artie Folse.
This is the wrong LED to use -- it seems to want more juice than the board can supply -- but it's all I had on hand at the moment. Anyway, I'd like to pimp Spark Fun Electronics. I grumbled at them for what I thought was a quality control issue, but it turned out to just be a strange solder joint required in the new board revision.
I plan to use this little guy to control the knobs and two-line serial vacuum florescent display for the radio head unit for my car. Yes, I know aftermarket head units exist; I just can't find one that runs on 6 Volts.
If you are wondering why Muslims in your country aren't very happy, here is a little clue. Do you think it might have something to do with the way your government implicitly and explicitly encourages white British people to hate, fear and suspect those of brownish color?
No! Surely not!
Turns out that was all bunk; we were supposed to be allowed to bring aboard non-liquid items purchased after the first security checkpoint. In fact, the second security checkpoint wasn't even really supposed to be operating as a checkpoint; they were just supposed to look for "suspicious" people and give them an extra search. But somehow, no one got the memo (or whatever), and they just started confiscating everything.
And then, to add insult to injury, as soon as I arrive in the US, the freak-out starts to wind down. Goddamnit. I don't ever want to fly again.
I returned the busted suitcase today, and purchased the fine example of 1980's industrial design at a "car boot sale" (the term Britons insist on using when they mean "rummage sale") pictured below.
It is amazingly tough, though I don't care for the little dinky wheels at the end. It tends to tip over. However, the 14 pounds I payed for it beats the hell out of 55 pounds for the other case.
Anyway, it's off to bed with me, for my three hours of sleep!
I could probably finish most of the testing on the airplane from London to Newark, but alas, my laptop (and everything else) will be in the cargo compartment. Bugger.
In a stroke of magnificent glorious wonderfulness that has so typified this trip, I had to buy a big hard-sided suitcase so that there might be some hope my laptop and camera might return to me in more or less working condition. The guy at the luggage store spent no less than ten minutes explaining to me the great quality of this suitcase over the others. He told me of its great reputation among world travelers. He told me of the tradition of craftsmanship that lead to its creation. He told me of the proud heritage of its manufacturer, a good solid British company.
So, I bought it. It cost fifty pounds. As soon as I put something in it, the goddamn handle riped off.
Well, that fits well into the common assessment of British engineering and manufacturing: Overpriced and shoddy. I think I might prefer to rub dog shit into my hair than go to Gatwick on Sunday.
- Random Numbers I Typed
- Dollars to Donuts
- Important Financial Data
- Grumpiness (Seasonally Adjusted)
Special thanks to Chris for setting me straight on database migration.
I met a traveller from an antique land
Who said: `Two vast and trunkless legs of stone
Stand in the desert. Near them, on the sand,
Half sunk, a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed.
And on the pedestal these words appear --
"My name is Ozymandias, king of kings:
Look on my works, ye Mighty, and despair!"
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away.'
Then we took the New Berlin Tours Third Reich Berlin: The Rise and Fall of Hitler's Capital. Utterly fascinating. It occurred to me that history is littered with governments that have gone berserk in one sense or another, and yet people who go into law and politics seldom study these situations. Someday, when I've got lots of money (har har), I'm going to establish a college at some nice university that gives degrees in constitutional law and political history. I want the graduates to understand constitutional law from the perspective of someone who is intimately familiar with how constitutions fail. Maybe they will finally understand why, and learn how to build republics so robust that tyrants will never be seen again.
And, since we weren't quite done yet, we grabbed some dinner and saw a Bach organ performance at the Berliner Dom. The music and the acoustics actually made me dizzy, it was so good.
I think it ought to be officially named the Adolf Hitler Memorial Parking Lot. The ruins of the bunker underneath could become the Hitler Memorial Septic Tank.
- The itinerary I received from the UCLA travel agency said
that Mimi would arrive at Luton at 9:05. I thought this meant
9:05 PM, because I expected to still be in Culham on Saturday
morning. Indeed, I had written 9:05 PM on my itinerary, and no
one spotted the error.
In the two days before she left Paris, I called her hotel several times. Not only was I unable to reach her, but she never received any of my messages. Also, the only emails she actually received were ones with messages like "See you soon!!!!" The two emails where I asked her to confirm the arrival time never left my mail server. Evidently, my mutt key-bindings are not UK-keyboard-friendly, so my "save message to queue and sent it" shortcut instead turned out to be my "postpone message to drafts."
In fact, she arrived at 9:05 AM, and waited at the airport for eleven hours. Fortunately, she found a place to check her email, and figured out what I'd done wrong. Amazingly, she did not kill me.
- My payroll back at UCLA is busted, and so I'm not getting paid any more. I don't think I'll be able to fix it until I get back to California. That leaves me without $2200 I was counting on.
- Something is wrong with my bank, so I cannot transfer money from my savings account to my checking account. Upshot: I'm completely broke.
Update: My bank suddenly un-fucked itself, and my payroll came through. That knocks my blood pressure down a couple of megapascals.