I learned today that Robert E. Lee had a pet hen that laid an egg under his cot every morning. I also learned something new about one of the finite element tools I use. And I was reminded of how irresistible the ginger animal cookies from Trader Joe's are.

Now if only I could learn to put work aside without guilt.

Patxi accidentally recorded over the answering machine message the other evening. I recorded a message which instructed the user to cry havoc and let loose the puppies of inconvenience, or just leave a message. Patxi didn't find that as amusing as I did, so we recorded a new message:

Meow, meow, meow, meow.
Meow, meow, meow, meow.
Meow, meow, meow,
Meow, meow, meow, meow, meo-beep!.

• Currently drinking: Vanilla hazelnut tea with milk and honey

I did see The Matrix Reloaded this evening. I enjoyed it. And now I want to go to bed. But someone nearby is playing their music at high volume, enough so that it's difficult to sleep. Perhaps it's to celebrate a graduation. Usually it's quiet here even on weekend nights.

I thought to myself this afternoon, I want to go see 'The Matrix Reloaded.' So I picked up a book to read during waits and walked out the door. On the way to the BART station, I thought, Wait, we're out of coffee. I should go to Peet's. So I bypassed the BART station and walked to Peet's. I bought the coffee, and thought Wait, I can still make it to a matinee showing. But I'm not going to make it unless I eat something. So I had a bite to eat, and then walked to the United Artists cinema in Berkeley. I looked at the show times, and thought, Wait, I'm twenty minutes late, not ten minutes early. I'll see it another time. So I walked to the BART station and came home.

I haven't walked south on Shattuck from north Berkeley for a long time. I used to live in north Berkeley near where Shattuck becomes Solano, and so I walked that route every day. I seem inclined to vivid memories recently, and the walk brought many of them. Here's the place where I lived during my first year of graduate school. Here's where I ate with Scott and Kathy when they visited me in California, after we took our trip to the old-growth redwood forests where the speeder chase scenes from Return of the Jedi were shot. Here's the stylish pizza place I passed every day, but where I only ate once. That was with Luke, before he returned to Maryland. Here's the French Hotel, with a man sitting outside, sipping coffee and singing softly in Spanish. Here's Black Oak Books, the first book store I visited in Berkeley. I stopped there when I was searching for housing; I was discouraged at the time, and certain I was lost, but the books (and friendly people with directions) cheered me immensely.

Here's one of the few buildings that used to be open when I walked home. It was a fast food joint then, a KFC, I think. Now the signs are gone, and the windows are dark and covered with graffitti. And here's Berkeley Espresso; they have wi-fi access, now. Here's the Berkeley Public Library, which was under renovation the entire time I actually lived in Berkeley proper. Here's a man playing a stringed percussion instrument -- a harpsichord? I know I've seen him before. Here's a man playing jazz on a keyboard; I've probably never seen him before, but it feels as though I must have.

And here's the BART station again. I see that often enough now. Time to go home and finish my book.

• Currently drinking: Red tea

Slashdot linked an amusing article on Office Hour Habits of the North American Professor. I think they missed some categories.

It's overcast and windy, but it's not supposed to rain until tomorrow.

• Currently drinking: Coffee

I just read an interesting piece on nostalgia.

Appropriately enough, it sparked a memory. Jeremy, my best friend in high school, was a big fan of Steven King. I remember listening with him to one of King's books on audio tape. I've forgotten the title of the book, but the premise is that a plane flies through some anomoly into the not-quite-gone past. All the passengers awake during the passage through the anomoly disappear, leavng only the passengers who were asleep. The remaining passengers manage to land the plane, then spend some time plotting against each other, being noble, going crazy, and all the other things you'd expect of King's characters. And then the eaters of the past come.

It's interesting how trains of thought derail into memory at times.

Memories from the Simpson's:
Nelson: How many monkey butlers will there be?
Bart: Only one at first, but he'll train others.

It's just as well that I will never have a monkey butler. Only ill could come from such a thing.

Heidi left this morning. I helped clean a little last night, and bought her bike from her. That solved her quandry of how to ship the bike, and it gave me the impetus I needed to finally replace my trusty-only-in-spirit pedal-powered steed. I took my new bike to Missing Link this morning to get it tuned up and to get a replacement for the cable to the rear brake. When I returned home this evening, I took the wheels off my old bike and put the whole thing in our storage area. The new bike is ligher, is more suited to road riding, has better shifters and brakes, and has a frame more nearly my size.

This morning, someone sent a link to a NY times article on Computing's lost allure. The point of the article is that undergraduate applications to computer science have dropped dramatically, in part because entering students have realized that they might not leave school to become instant millionaires. I'm curious how this will affect mean undergraduate performance and program retention rates. When I began my undergraduate career in 1995, computer science was a popular major, but after the first few weed-out courses, most of my remaining peers in the program seemed genuinely interested in CS. Those who were not fled to a less technically demanding major: business with a concentration in IT, usually.

I know there are people who enter undergraduate programs purely for vocational training, and sneer impatiently at breadth requirements and at anything that might not be directly applicable. Then there are those who move to the opposite pole, and sneer at anything that seems like it might possibly be applicable. Unfortunately, I know more people who grow out of the latter attitude than people who grow out of the former. I prefer the middle ground of the pragmatic dreamer. From what I know of history, the division between the pure and applied is a modern conceit anyhow. It seems to me to be a useless dichotomy.

I helped Heidi carry a box to the post office this afternoon. It weighed about fifty pounds, and carrying it was enormously awkward. I ended up transporting it on my head for much of the distance; that way at least I didn't have such trouble keeping my grip.

As I headed back home after lunch, I stopped by the post office again. I now have a book of antique toy stamps and a pile of dollar coins. Hee hee! I think the dollar coins are enormously amusing, though I'd be hard pressed to say why.

And my revised block works. It's not very long, but it took much longer to get right than I expected. I was transposing something that should not have been transposed.

So far, it has been a good day.

• Currently drinking: Bigelow vanilla hazelnut tea with a drop of honey.

I installed GnuPG 1.22 and Mozilla 1.4b this morning. Both installations were surprisingly painless.

Patxi and I have had a small cone filter for coffee almost since we moved here. Esther was impatient with the wait that the small filter entailed, and so now we have a large cone filter. The large filter is sufficiently large that it's feasible to brew a pot of coffee rather than a cup. So this morning I brewed two cups of coffee in the pot. And since Patxi is traveling, I drank both cups myself.

I also made a pot of Earl Grey tea later in the day, and a cup of peppermint tea this evening. I took a break this afternoon to walk to 99 Ranch to buy a tapioca milk tea, too. And I've had several cups of water and juice.

The code I'm working on went from running in 14 seconds on my test problem to running in 60 seconds. So much for my improvement. I've halved the memory requirement, though, and I know where the performance problem is and I have some idea how to fix it. I've even written the modified code which I hope will run faster. But before I can get it to run faster than my original code, I have to get it to run at all. And right now, I have an indexing error.

Coding work is therapeutic. So is jazz. So I'm coding and listening to jazz. I'll catch up with the rest of the world this weekend and next week.

• Currently drinking: Water

I finished My Brother Michael last night. I highly recommend it. Now I want to travel in Greece.

Cleaning my paper pile produced more measurable results than most of my activities today. I spent most of my productive hours debugging to the background sounds of Alistair Cooke's Letter to America, Sound's Eclectic, and To the Best of Our Knowledge. The last program was on coffee, and was moderately interesting.

I made stir-fry this evening. Soba noodles, baby corn, mushrooms, red bell pepper, brocolli, tofu, an egg, black bean sauce, and soy sauce. Quickly cook the veggies with soy and black bean sauce while the noodles boil, then add noodles and egg. Easy, filling, and nutritious. I have not cooked such a good meal for myself in a while. It almost made up for the drain of a day of debugging.

I watched an episode of Nova next door, did some more work (not all of it debugging), ate the last few ginger cookies, and spent some time surfing the web. And then I made tea, sipped it... and felt blue. My life does not look particularly grim right now by any reasonable measure, so I can only hope this mood is a reaction to sleepiness and mild allergies. The right remedy is probably to sleep a while.

I just weeded all the pages of scrap paper scribbled with calculations out of the stack of papers in my backpack. The size of the stack decreased from four inches thick to two inches thick. I'm going to leave some of the papers that I'm not actively using at the office this evening, and I expect that my backpack on the ride home will be as lightly loaded as it has been in months.

I just saw myself in the mirror as I came back from a trip to get more ginger cookies in the kitchen. The image in the mirror was much more eye-catching than usual: I'm wearing green sweatpants and a fuzzy blue jacket over the bright red t-shirt with I Love Math printed on it that I got from my college roommate some years back. I was carrying two cookies and wearing an enormous grin.

I've seen pictures of myself eating cookies when I was young. Some things have changed little over the years.

When I first moved to El Cerrito, the El Cerrito Plaza Mall was a sad place. There was a Waldenbooks that I would sometimes visit, and there was a farmer's market on the weekends, but those were really the high points. There was a place where you could get coffee and doughnuts, but it looked sufficiently frightening that I never went in.

Then the renovations began. There's a Barnes and Noble outlet, an Albertson's grocery store, several good restaurants, and now a Trader Joe's. I bought a tub of animal-shaped ginger cookies there this evening, and they're great. Strong ginger flavor meets camels and cats; how could they be anything but great?

I ate dinner with Heidi at Yammi Sushi. It is very likely the last time I'll get to eat dinner with her, which is sad. But it was a good dinner at least.

Last night and this morning I read Born to Run by Mercedes Lackey, which was good for a couple hours light entertainment. I finished reading Symmetry this afternoon, and finished the first half of Mary Stewart's My Brother Michael this evening. Symmetry is an excellent little book; Hermann Weyl had the same taste in popular mathematical exposition that I admire in Ian Stewart. And My Brother Michael is difficult to put down. I heard someone comment that the Greek countryside was one of the major characters in the book, and it was a very true comment. It makes me want to visit Greece.

I took another long walk in the sun this afternoon, too. I meandered up the hill to the top of Solano, spent some time browsing the book stores, and then wandered home. On the way back, I stopped at Albertson's to buy bread and cereal. I made chili for dinner. It turned out well, and I shared some with Patxi, some with Mike, and some with Heidi. There is just enough left for lunch tomorrow.

I'll have to season the chili this way again. I put in less cumin and chili powder and more lime juice and black pepper than I usually do. More cumin might have been nice, but the lime juice and black pepper went well.

Esther finished The Years of Rice and Salt, and I've now loaned her a Terry Pratchett book. And I loaned Mike several books. Loaning books brings me much glee, almost as much as reading books does.

This morning I talked to my parents and washed the dishes. Then I walked to the top of Solano Avenue, had a cup of coffee, read the first hundred pages of Symmetry by Weyl in the sun, came home, and took a nap. I read some fiction and loaned Tracy a few books. Then I went to Heidi's going-away party, from which I returned a few minutes ago.

I'm reminded on such days of a fundamental truth. I'm an introvert. I like people well enough, but I find it refreshing to read in the sun, while parties drain me somewhat.

I think I'll read for half an hour before I sleep.

The paper is done and submitted. It's always a relief to have deadlines finally pass.

I saw two interesting talks today. The first involved the flow of the atmosphere of Jupiter. The speaker was doing some eigenvalue computations to study the stability of some flow patterns, and had a clever way of solving the problem quickly. I think he accidentally reinvented a standard technique, but it was still an interesting presentation, and an excellent job for a class project. Besides, any presentation that starts with a model of the atmospher of Jupiter earns inherent coolness points.

The second talk was interesting at two levels. From a technical perspective, it was moderately interesting. But it was much more interesting as a reflection of a personality. There was a lot of beautiful mathematics connected to an application as a sort of afterthought, even though the application was supposed to be the motivation for the talk. I prefer a mix of applications, mathematics, and algorithms, but I've been reminded several times recently that I have peers who love one or two of those three and look at the others as repugnant, trivial, or simply uninteresting. That attitude confuses me when I encounter it.

I read Reaper Man by Terry Pratchett last weekend. Or was it the weekend before? It was a fun book that required no particular effort to read. And I really like Pratchett's character of Death. Death likes cats and speaks in small capitals. How could I not like him?

I'm tired, confused, disgruntled, and sad about some things. But it's spring. The weather has been beautiful, and the daylight hours are long. I'm in good health, and can bike to and from school. I have work that I enjoy, friends and colleagues who are interesting and intelligent, and a big stack of books -- technical and not -- to read and enjoy and digest. And I have tea. So I'm happy, too.

• Currently drinking: Red tea

I received a conference announcement and call for papers this afternoon. The announcement included the following memorable description of the Yucutan Peninsula:

Cancun is situated in the state of Quintana Roo on the eastern coast of Mexico's Yucatan Peninsula, a seal-head shaped land mass that stares longingly towards Cuba from Guatemala and Belize.

The text I just finished writing for the Internet measurement paper does not include this phrase:

We construct a virtual network, a tree-shaped mess of links that stares longingly toward the real network from realms of ethereal abstraction.

If the objects in my paper stared longingly at each other, the paper would probably be more memorable than it is now. Then again, characters staring longingly at each other doesn't make a bad work of fiction any more memorable, or any better. If anything, it makes it worse.

• Currently drinking: Cocoa

The Matrix Reloaded his theaters tonight. I will not see it for a few days, though. I'm in paper-writing mode at the moment.

It would be more accurate to say that I'm in paper-writing mode except when I'm not. This afternoon, I was definitely not in paper writing mode. I went to a lunch meeting to listen to a talk on robust MEMS design in the face of uncertainty. Then I went to the matrix computations seminar to hear about comparisons of two methods for solving ill-posed least squares problems. I talked to a visitor from Sweden, and then was back in my office for but a few minutes before Kahan knocked on the door and spoke the words I was going to tell Jim why he's wrong, but he's not here now, so you'll do. It was an interesting conversation. It was not writing.

I was asked three times today how near I am to graduation. It will be Soon, I'm sure. When will Soon be Now? I don't know. But I do feel like moving on, so Soon will be Now in the next year and a half. I hope.

Some devices I helped simulate are being tested now. I'm excited. I want to hear how closely the simulations match reality.

I look forward to Friday night. I want to go to bed before 2:00. I want to shut down my computer and read a book. I want to remember BBC, my family's Big Black Cat, who passed away earlier in the week. I want to buy groceries, clean the sink, and do mundane things. I want to let my stomach recover from too much coffee and too many meals skipped.

The academic semester has its ebb and flow. It's the end of the semester now, and it doesn't matter that I'm taking no classes. The end of the semester still wears me out.

And now, back to writing.

Saturday night, a computation I'm working on took four hours. Last night, it took four minutes. Tonight, it takes thirty seconds -- and I expect that to go down to fifteen seconds shortly.

Most computer scientists I know share certain personality characteristics. Among them are a love of puzzles, a preoccupation with program performance, and a mildly obsessive streak. I'm worn out right now -- but I'm having a lot of fun.

• One of the joys of starting a simulation that will take five minutes to run is that it is a guilt-free excuse to take a coffee break (or non-coffee break).
• Did you hear about the crazy dyslexic who said Lick them all, Dog will know his own?
• I think a tea kettle with a calculator built into the side would have been a perfect mother's day gift. Perhaps it would have been silly, but it's the pot that counts, after all.
• I spent time with Heidi this weekend, watching old Babylon 5 episodes (two of them), eating dim sum, and enjoying the sun. In less than two weeks, she'll be moved out of state. That puts other time demands in perspective.

• Currently drinking: Black coffee

If I hit my head, it would hurt.

Suppose I had a bat. I selected this bat at random from a pile of bats between 12 inches and 12 feet long, but on average it's probably about 3 feet. I suppose that the bat is made of an alloy which is at least 3 percent titanium. I will approximate the shape of the bat by a cylinder. If I hit my head with the bat, it would hurt.

Why do I have such trouble convincing people that a more general statement is sometimes easier to understand than a specific case?

I can't decide which is more rude in e-mail: huge fonts, bright colors, or enormous attachments. The combination of all three is most obnoxious.

• Currently drinking: Bigelow cherry vanilla tea

I jigged my way from my room to the kitchen to fix myself a cup of tea earlier this evening. Patxi and Esther were in the living room, and Esther was reading a book I loaned her. The Years of Rice and Salt by Kim Stanley Robinson is an excellent alternate history developed from the question How would history have developed if the bubonic plague were a little more virulent and killed 99 percent of Europe's population? As I waited for my tea, we had this conversation:

D: How do you like the book?
E: I like it. And it's good now, since I should learn about Islam for my exam.
D (continuing to dance a little jig): Cool.
E: You seem awfully happy. Are you twitterpated?
P: She means Have you found a girlfriend?
D: No, but I get to explain sparse linear algebra to people who might not care.
E: Hmm. It is spring, you know.
D: I know. But in this case I'm just in a good mood. No twitterpation, alas.

And I am in a good mood. And I should probably finish this subsection of the extended abstract I'm helping to write, and then go to bed so that I can be in a good mood again tomorrow.

• Currently drinking: Water

I'm enjoying my favorite dessert: tea flavored with grenadine and vanilla, sharp cheddar cheese, and graham crackers. It probably won't be my famous dessert tomorrow, but it sure does taste good now.

I had a conversation today which began with the words So I have this intuition from quantum mechanics. I know only a very few people who reason about classical mechanics based on ideas from quantum. But his intuition was right. So I'll run a few more simulations, and we'll see where we go.

• Currently drinking: Monk's blend

It's a quiet sort of evening. I'm listening to Sounds Eclectic, thinking about a graph-theoretic problem, and sipping tea. Sounds Eclectic is good listening when I'm in a pensive mood, as I am now. And red tea with honey and lime is good for a sore throat, as I have now.

• Currently drinking: Red tea with honey and lime juice

I wonder if the German word krank (sick) and the English word cranky are etymologically related. I've caught some sore-throat-and-sinus trouble, and I was certainly pretty cranky about it until a few minutes ago.

Then I made myself a cup of tea and checked e-mail. A cup of tea is good for a day of ill health. I still have a headache, and the honey in the tea didn't make the sore throat disappear, but at least my belly is warm.

• Currently drinking: Bigelow cherry-vanilla tea.

I baked bread this afternoon. It had raisins and nuts, and though I should have added a little more salt, it was still good. Now I'm full, and the weight in my belly is tugging my eyelids shut. It's overcast, too, and so I've even less inclination to remain awake.

I thought of doing work this morning, but I did little. I suppose I can forgive myself for taking some time off on a weekend, but it's difficult. Self-forgiveness is a learned skill, and as with most learned skills, it easily grows rusty with disuse. I like to think that my work ethic is leavened with enough humor and common sense to make it a virtue, though, and I'm reasonable enough to accept that any work I do in a mood like this will need to be re-done later. So I take a break.

I spent time last night contemplating the books on my shelf. What began as a foray for space to store the soon-to-arrive additions to my collection quickly turned into a rumination about what attracts me to books. My most beloved books show the signs of wear. Some of my technical texts have creases in their bindings, and their corners are eroded from too many trips carried with me in my backpack. Beloved books like Moo by Jane Smiley and Iron and Silk by Mark Salzman show similar signs.

And then there is E.T. Bell's Men of Mathematics. Bell's descriptions are not without historical flaw, but I still love this book. The pages are full of descriptions of great mathematicians as people: liberals and libertines, militants and mystics, brilliant teachers, physicsts, judges, and museum curators. These are Bell's heros, and it shows in his writing.

Bell describes the mathematical contributions of each of his characters, but I most enjoy the book for the characters themselves. I read non-mathematical history for the characters, too. In history, fiction, news, letters, and blogs, the degree to which people's stories are involved is a strong indicator of the interest I'll have. I think this is so for most readers I know.

• Currently drinking: Earl Grey

P: The Dell catalogue came in the mail.
D: You know they're planning to put a little farmer logo on front of their new computers, right?
P: A farmer? What?
D: The farmer in the Dell. It's a little like Intel Inside.
P: That's awful.
D: I try.

The sky to the west is bright blue, with a generous helping of cumulus. The sky to the east is covered by a solid wall of clouds the color of wet slate. The wind is blowing, but I'm not sure whether it blows east or west.

I took some time to read fiction this evening. I finished The Briar King by Greg Keyes a few minutes ago. It has potential, I think. I reached the end and felt like I'd made it through a very intricate set-up to an interesting story. Unfortunately, the end of the set-up was also the end of the book. I'll keep an eye open for the sequel, and I'll keep my hope that Keyes has more respect for timely conclusions than Robert Jordan does.

Bai visited Berkeley today. He arrived at the office a while after 5:00, saw David G. and I pacing in circles and talking about Poisson problems, laughed, and said It's a Friday afternoon. And it was indeed. I showed Bai some of the things I've worked on recently, and we ate dinner. I like talking to Bai. He has an interesting perspective and a very big heart.

• Currently drinking: Water

The evolution of a computation:

• Derive a finite element for consistent electromechanical simulation.
• Try to explain to a friend what I just did. Fail. Swear.
• Try to explain to an advisor what I just did. Have error in derivation pointed out. Swear.
• Finish working out the formulas.
• Think about implementing formulas. Shudder
• Eat a bowl of ice cream.
• Implement the element. Write sanity checks, which fail.
• Tell the computer it's mother was a goat.
• Debug. Swear. Debug.
• Tell Matlab thou'rt a stupid-head!
• Element passes sanity tests. Try it in a more complete test.
• Give up. Sleep.
• Discover the inevitable sign error. Roll eyes.
• Puzzle over why the simulation doesn't behave as expected.
• Puzzle more.
• Discover expectations were incorrect. Swear.
• Get consistent results. Try larger example.
• Large example is painfully slow.
• Think about appropriate insults for an inanimate object.
• Rewrite element in C. Now bottleneck is elsewhere.
• Rewrite assembly in C. No more bottleneck!
• Try larger example. Bottleneck is now where expected.
• Record pointless list on bloc.
• Go to sleep.

Mmm. Sleep.

(Editorial note: Mentally calling the computer a foolish pig-dog in a Monty-Pythoneseque pseudo-French accent counts as swearing.)

There was a reception today to celebrate the launch of our newest high-power computing cluster. There was food, including interesting fish sandwiches. They were a combination of aram sandwiches and sashimi. I don't think I'd encountered anything like it before, but it was quite good.

I need to make more meals for myself. Between events like this reception, dinner with friends, and too many hours spent working on the recently-finished paper, I've not cooked much recently. I enjoy cooking, and I eat better when I cook for myself.

Anyhow, those green beans are going to fly south if I don't eat them soon.

• Currently drinking: Earl Grey