I spend much of my time doing calculations that are not too taxing on a modern computer. I set them up, start them, and work on something else for anywhere from a few seconds to half an hour, then come back to look at the answers. At least, that's what usually happens. Some days I mis-estimate what is small, and halfway through the calculation my machine comes to a grinding halt as my tiny computation eats all the available memory.

Today seems to be one of those days.

The word thou is archaic now, but before it fell out of use, thou was the second person singular form and you was the second person plural. The lapse of this usage that made you bear the weight of both the singular and the plural has lead to the introduction of the plural forms y'all and youse in some American regional dialects. The use of the older thou form persists in popular culture through older works of English literature, including the plays of Shakespeare and the King James translation of the Bible. Unfortunately, the thou form may appear in literature classwork, but it does not typically appear in grammar class. Consequently, some people think thou is simple a more formal way of saying you, and abuse the poor pronoun ferociously. Pronoun abuse is a peeve of mine; but since I lack the resources to run a pronoun abuse hotline, I'll settle for writing lists like this one.

How to use thou

• Use thou for singular and you for plural. It is not correct to thunder from the pulpit Thou art sinners! unless perhaps you're addressing someone with multiple personality disorder -- and in that case, don't you think you're being a bit hard on the poor fellow? It would be grammatically correct to say You are sinners -- except thee, though the I will leave the truthfulness of the statement to the religious authorities.
• Conjugate! You would wince (or perhaps thou wouldst wince) if you heard someone say we am going now; the phrase thou are going now is just as wrong. It should be we are going now and thou art going now. In general, verbs that go with thou end with an st, though there are irregular verbs that don't fit (like art). Thou dost, thou makest, thou thinkest, thou hast.
• Be consistent! Unless you need to do so for some specific reason, don't switch between the verb forms in mid-sentence That means that if you start with thou, you should use thy and thine for possessives. If you're unsure how to use thou correctly, why not use the modern forms?
• Do not mistake thou for a particularly impressive or authoritative form of the modern you. It has a specific meaning; that meaning should be respected. If you're unsure of the grammar of the old form and still want to give your prayers and hymns a sense of religious grandeur, use capitalization. And if Terry Pratchett's personification of Death can speak in capitals all the time, surely you can manage it for a single word on occassion.

Rain is falling and playing percussion on the roof. I'm glad to be indoors, pondering cosmic questions like What are tomatillos related to, and how did anyone think to make salsa from them? I often wonder about the origins of various foods and drinks. Who would think to make drinks from rotted potatoes or fermented mare's milk? I've been told olives are almost inedibly bitter in their natural state (and some friends would claim they remain inedible even after processing). Who first thought to pickle them in brine? The oxalic acid in rhubarb leaves is toxic, though not nearly so much so as the neurotoxin in blowfish; how did we end up eating these things? Even my cup of tea -- flavored with osymanthus flowers today -- is a bit of a mystery. According to one tradition, tea was discovered when a few leaves blew into a Chinese emperor's kettle, but that story is likely apocryphal.

I finished my corn chips and salsa with lunch. That salsa is wonderful stuff. My friends all found it too salty -- but I've always had a weakness for salty foods, to the point that my flatmate once suggested we install a salt lick. With the chips and salsa gone, my cupboard looks startlingly bear. I have the ingredients for sour cabbage for dinner, with some bread and cheese on the side, but then I will need to visit the grocery store.

I briefly visited campus today, before the rain started, and checked out a book on the physics of musical instruments. I also photocopied an article on the effects of air loading and acoustic radiation loss on the sounds of kettledrums. To all appearances, the books in that library are organized by Library of Congress codes, but the journals are organized alphabetically. I could be mistaken; whether I was mistaken or not, though, I certainly was bewildered. By the time I wandered out of the physics library with my prizes in hand, it seemed like high time to have a cup of coffee and a snack.

The Free Speech Movement Cafe on campus is in the basement of Moffitt Library, which is next door to the Doe Library Building where the physics library is housed. I often enjoy something there when I'm visiting the libraries. Despite the spring break holiday, the cafe was open and busy today. I found a table where I could skim my article, but spent less time reading than I spent listening to the group at the next table, who seemed to be discussing the results of some experimental data on groundwater contamination. While their discussion was spirited and sounded fascinating, it was also distracting, and so I finished my coffee, got on my bike, and headed home.

The rain started when I was only a few blocks from home.

Yesterday, Winnie and I went to Stanford, where made a lunch of garlic bread, cheese, and oranges; played frisbee barefoot in in the grass for a while; and met one of Winnie's college friends and his girlfriend. They were visiting from the East Coast. The four of us went into the city, walked along the Golden Gate Bridge, rediscovered the joys of driving in San Francisco, and ate at a nice Italian place. Then I came home and slept.

Today, we took the BART to Berkeley station and walked back home. We stopped at Black Oak Books along the way, and browsed through the used cookbooks. I have not done that in quite a while. It was a beautifully sunny day, though the breeze carried a chill with it that told of the end of our midsummer-in-March weather. I made us a cross-cultural dinner: French onion soup followed by Chinese stir fry over rice, with strawberry ice cream for dessert. We shared our meal with Patxi, Esther, and Mike. Then we watched Muppets from Space -- which I found hilarious -- and then it was late, and Winnie headed home.

Wednesday, I will be back to work. Until then, though, I'll enjoy the chance to read and play and do non-academic things.

I have been happily busy. My talk last Saturday went well; my hike this Saturday was fun; and in between there were some fun things and some not-so-fun things and a lot of general doings.

I continue to work my way through a volume of short stories by Dorothy Sayers. A friend loaned me three sci-fi books by Michael Flynn, which look interesting. I have the new SIAM Review, which I've perused in part, and a copy of Alistaire Cooke's Memories of the Great and the Good. It had been on my wish list for a while, and I finally decided to buy it -- not long before the last of his Letters from America. I will miss his voice on the radio.

I now own Horn and Johnson'sTopics in Matrix Analysis, which I've missed ever since my former office mate graduated and returned the copy our advisor had loaned to her. Barenblatt's book on similarities and intermediate asymptotics should arive soon. I'm still making my way through Fowler's book on code refactoring and through Rob Phillip's excellent Crystals, Defects, and Microstructures. I have a bounty of light reading and of technical reading, both.

At the end of the meeting last Saturday, there was an interesting round-table discussion about education in computational science and engineering. The immediate question was from numerical computation experts at the national lab who asked How can we ensure there continue to be people with the right background available to hire? The ensuing discussion was wide-ranging and heated, and covered everything from how high school might be better organized to the effect of the job market to the structure of undergrad curricula in engineering, computer science, mathematics, and the physical sciences. I listened to the argument, and I agreed with many points made -- and I pondered my own thoughts quietly.

The word amateur now has a negative connotation -- an amateur is a bungler, or at least someone who lacks the skill to be a professional. Yet that is not the original meaning of the word. From the Latin, an amateur is a lover -- one who pursues a skill for the sheer joy of it. I would like to see more students become professional scientists and engineers of various stripes, but I really want more amateurs: people who build their own physical models to better understand every-day phenomena, for example. I also think we need more amateur historians and poets, philosophers and writers, engineers and naturalists. The world is a marvelous place, and we should take time to marvel and question and explore for ourselves.

Mark Zimmermann discovered my pages, first Sandy Mack's sermons and then this blog. He seems a kindred spirit, with wide-ranging interests much like mine. In an e-mail, he reminded me of the question about whether you can hear the shape of a drum -- given a membrane, how much can you tell about the geometry by learning the frequencies of the modes of vibration. Quite a bit, as it turns out. Jim mentioned the same body of literature when I first mentioned drums to him. It's not quite the same problem that I'm helping Cynthia simulate -- but it's an interesting problem nonetheless.

I ran another resonator simulation this week, and also another drum-head simulation. Both simulations were intended as much to test some new machinery as anything else. That's good, since I'm suspicious of the results of at least one of those simulations -- but for reasons that have nothing to do with the machinery I wanted to test. I also went to the floating point committee meeting this Thursday, and was party to a four-hour discussion on extended semantics for NaN (Not-A-Number). I was grateful when the meeting ended and I was able to meet with Winnie and play Frisbee for a while. I also helped my neighbor with a calculation involving molecule alignment, finished a fluid mechanics homework problem, and learned a little more about thermal effects at grain boundaries in polycrystalline silicon. It was a busy week.

It was also another beautifully sunny week, and a week of good food. Last Saturday there was a banquet dinner after the meeting, and I got to take home some leftovers. I had duck for a few days. When Winnie visited on Sunday, we got a loaf of olive bread, tangelos, and a delicious brownie. I was so impressed that I walked back to Andronicos on Monday to buy some bread and cheese, more tangelos, and a gallon of milk. On Thursday evening, I went with Winnie to the store, and we bought grapes and cheese and a baguette; and yesterday, I went to Trader Joe's and got some sesame thins, corn chips and tomatilla salsa, tangerines, and grapefruit Italian soda.

You might have the impression from these grocery lists that I subsist mostly on bread, cheese, and citrus fruit. It is not so -- I eat salad regularly, too, not to mention sour cabbage, noodles, rice, and beans. On the other hand, I do dearly love good bread, cheese, and fruit, and I've been eating a lot of all three lately.

And this week is Berkeley's spring break. I look forward to enjoying a couple days off, and also to finishing a little of my work backlog.

The weather this week has been balmy. It has reached 80 in many places, and it is supposed to remain this warm through Saturday. I have enjoyed the heat during my bike rides and walks, but I'm not looking forward to sitting in class today. On Tuesday, the heat was stifling in the classroom where my fluids course meets. I expect it will be the same today.

Patxi told me last night that he and Esther are planning to move. They've found a place they really like, which may open in the next few months. I'm not sure how the timing will work; our lease doesn't run out until June, I think, and none of us are in a tremendous rush. I understand why they want to move: our two-bedroom apartment, though spacious for two, is not so spacious for three; and I think Esther will be more comfortable sharing housing with her boyfriend than with her boyfriend and his quirky flatmate. Still, this is drattedly inconvenient. I'd hoped not to move again until after graduation.

• Currently drinking: Black currant tea

I'm making a movie of the (simulated) oscillation of a coupled micro-resonator system. It's not quite Oscar material, but I'm very pleased with myself.

I should see if I can get Peter Jackson to direct the sequel, Lord of the Shear Rings.

I stuck my head through Mike and Tracy's door this evening to show off my new hat, and this conversation ensued:

D: Did you know the Siberian crane dabs a collar of mud around its neck as part of its courtship ritual?
T: (laughing) I'm trying to decide which is funnier, the crane or the hat.
D: Looks like you're leaning toward the hat.
M: What I want to know is, where did you find out about the crane?
D: I just finished a book on cranes by Peter Matthiesen. I gather from your expression that you find the hat amusing, too? I got it to keep the sun off my neck.
M: Well... you look a little like a hybrid between a geeky computer scientist and someone who should be named Billy Bob.

The Prairie Home Companion radio show this week was a repeat from earlier in the year. It was done in Nashville, Tennessee, and includes a skit of concert musicians being taught to guffaw, wear coveralls, and keep chickens handy in order to make the Grand Old Opree more authentic. I suppressed the urge to slap my knees and say hee hee hee! and Mike's comment -- but just barely.

• Currently drinking: Red tea with rasberry

I've written little lately, in part because I've been busy, and in part because I've spent my leisure time enjoying the sun. But I'm working on a lot of interesting things, and I feel inspired to share.

1. Computer animators and game developers use physics-based simulations to create some incredibly convincing effects. Sometimes they resort to models that are fast and look reasonable, but are physically unrealistic; but as computers get faster, they can get more of the physics right and still run fast enough to remain on schedule.

   That's great for graphics, but what about for sound? Several professors and students at Berkeley are working on creating sounds on a computer by simulating the real physics of objects bounding off each other, or by simulating what happens when a musical instrument is played. Cynthia, a graduate student researcher in the department, has been working on simulating drums for computer sound generation. I've been helping her build some of her finite element models, which so far include only the vibration of the drumhead, but will soon include the interactions between the drum skin, the drum body, and the air inside and outside the drum. I hope to use this for the term project for my fluids class -- it's an interesting computation, it helps someone else out, and I might be second author on some related publication.

2. When you hit a drum, the sound dies away after a brief period. Why? Some of the sound energy is absorbed by the walls of the drum; some radiates out into the room, where it is absorbed by the ceiling tiles, the carpet, or the household pets; and a very little bit turns into heat energy in the air itself.

   Now, what if your drum was a bit of silicon, a small fraction of a hair's width in size, and it vibrated at around the same frequency as the carrier signal for your cell phone -- 2.4 billion times every second. The vibrations of this drum, too, will eventually die away, but the energy will be dissipated in different ways from a bongo drum. Some of the energy will escape through mechanical connections to a larger chip of silicon, to bounce around and eventually be absorbed, perhaps into the glue used to hold the chip to its packaging. And some of the energy will turn into heat inside the material itself.

   Find a rubber thick band, like the type used to hold stalks of celery together in the grocery store. Stretch it quickly between your fingers, and hold the stretched band to your lips. Can you feel a slight change in the temperature? What about when you let the rubber band relax? Rubber is a remarkable material, but in other materials, too, fast stretching and compression can cause changes in temperature, and vice versa. When an elastic material is stretched, if the stretching isn't uniform then the change in temperature will also not be uniform. Heat will flow from the warm spots to the cool spots, and in the process, some of the energy that was put into the material by stretching will be dissipated away, so that it can no longer be used to do further mechanical work. This thermoelastic damping is negligible for your bongo drum, but not for micrometer-size MEMS resonators.

   Together with researchers in the radio-frequency microsystems (RF MEMS) group and colleagues in computational mechanics, I'm involved in trying to figure out how these high-frequency resonators vibrate, and the ways in which those vibrations die out. In particular, right now I'm involved in looking at a test problem -- in a vibrating beam, how much energy is lost due to thermoelastic damping? We also hope to look soon at how much energy radiates away through the anchors by which the beam is connected to the rest of the chip.

3. Suppose you drop fine grains of sand into the water, and watch them drift downward toward the bottom. If you drop ten grains of sand together, will they fall at the same rate at which a single grain of sand would fall alone? No! Water has some viscosity, and so each of the ten grains of sand pulls its neighbors with it as it falls. Consequently, the ten grains fall faster together than they would alone -- a fact which will doubtless be astonishing to anyone with more experience in committee work than in physics. The last fluids homework involved a calculation of the descent of such a collection of slowly-falling particles.

4. If you slowly turn off a running faucet, the smoothly flowing stream will turn into a sequence of individual droplets before it finally halts completely. If you sufficiently push hard on the end of a column, eventually it will buckle to one side or the other. These are both bifurcation behaviors: sudden, qualitative changes which occur in many systems when some parameter (like the flow rate or the load in the previous two examples) exceeds some critical threshold.

   Finding the values at which such bifurcations occur is not always an easy task. There is some general-purpose software available for numerical bifurcation analysis, but many of the best software packages only work well for small problems. If the size of the problem is too large, these software packages run too slowly to be very useful. In order to extend the software that works so well for small problems to be useful for bigger problems, we use a projection method, in which we're able to examine a carefully constructed sub-problem which tells us all we need to know about the bigger problem. I have been collaborating with Mark, a math professor in Alabama, on an algorithm called continuation of invatiant subspaces, which should let us intelligently choose the sub-problems we need in order to find bifurcations both accurately and quickly.

5. I maintain a large linear algebra package called CLAPACK, which is a C translation of the venerable LAPACK library, a huge collection of Fortran 77 routines for solving a variety of problems in numerical linear algebra. It's a popular package, and I usually receive at least two or three requests each week from people who are having difficulty using the routines, or who don't understand which routines they need to solve their problems. For example, I recently had several exchanges with a gentleman who is studying the cable equation, which models neuron activity. He wanted to use LAPACK routines as part of his differential equation solver, but had trouble preparing his input in a way that made LAPACK happy. I was able to help him, and he sent an e-mail thanking me for clearing away one of the final impediments in his thesis research. I filed his thank you note where I can retrieve it easily; I like to have such notes available to comfort me when I'm forced to deal with inquiries written in broken English by those who have no grasp of what they're doing or why they're doing, but seem utterly convinced that the fault lies in some bug in LAPACK.

Dr. Seuss's hundredth anniversary was this week.

Big Q, little q, what begins with q?
The quick queen of Quincy, and her quacking quackaroo!

I remember, even after so many years. Of course, I don't remember the rhymes for any of the other letters. I was particularly attached to the letter Q, though. I still look fondly on it, even though now when I see the letter in isolation it immediately conjures thoughts of system energy or quality of resonance.

When I woke this morning, I had the theme song to Monsterpiece Theater stuck in my head. This spoof from Sesame Street of Masterpiece Theatre was hosted by Alistair Cookie (the Cookie Monster dressed in a bathrobe), and always began with a shot of the cookie monster chewing meditatively on a pipe, listening to the alphabet being sung to a sort of chamber music tune. Ah, Mr. Henson! I come from a generation whose culture is part Sesame Street and part The Simpsons -- both shows which allude to an amazing number of other bits of cultural trivia, so that they can act almost like a filter for the world. I've heard of seeing the world through rose-colored glasses; if I had to make glasses out of Sesame Street and The Simpsons, what color would they be?

Winnie asked me today why the Cookie Monster is blue. I had no immediate answer, but later I decided that it must be because of his diet. If the Cookie Monster ate more vegetables, perhaps he would be green. After all, pink flamingos are pigmented because of their diet. Why not blue Muppets?

Last night, I received around forty copies of an e-mail virus message. The mail told me that my computer was infected by a virus, and that I should execute the attachment in order to remove the infection. However clever the author might have been, his grammar was abominable:

Hello user of Berkeley.edu e-mail server,

Your e-mail account will be disabled because of improper using in next
three days, if you are still wishing to use it, please, resign your
account information.

Pay attention on attached file.

In order to read the attach you have to use the following password: 07407.

The Management,
The Berkeley.edu team

When I received the first such message, I was entertained. By the time I moved that message to the trash, there were four more in my inbox. That's when I wrote a filter so that I wouldn't have to think about it any further.

Yesterday was sunny and mild, and the weather is supposed to remain sunny for the rest of the week. I've started to bike to campus again. Though the weather provided no excuses, few voters cast ballots yesterday -- the registered voter turnout was around 43%. The low voter turnout didn't keep our governor from praising the electorate for passing his budget measures, saying Don't you love to see the people flexing their political muscles? The people of California are the greatest power lifters in the world. A commentator on one of the morning radio programs commented that Bush plans to stump in California soon, and that he hopes to ride on Schwarzenegger's popularity. That seems backward to me: Schwarzenegger has succeeded as a populist, not a partisan. His strength is in the combined support he has received from Republicans and Democrats. One of the callers on this morning's Forum program called Schwarzenegger a Democrat in Republican clothing; certainly his social views are more liberal than the views of many Republicans. In contrast, I doubt Bush's social conservatism and fiscal laxity will play well with California's electorate.

Were I Bush, I might stump in California despite misgivings about the state's politics, if only to enjoy the weather. Perhaps he'll spend some time campaigning by Fisherman's Wharf in San Francisco? What a circus that would be! I can imagine Schwarzenegger posing beside the man who pretends to be a steam-powered robot (complete with silver body paint and hoses which must have been cannibalized from at least three vacuum cleaners). I cannot imagine Bush doing the same.

The SIAM conference on Parallel Processing took place in San Francisco last week, at the Hyatt near Fisherman's Wharf. I did not go to most of the conference, but I did attend part of a workshop on Combinatorics in Scientific Computing on Friday and Saturday. I left early on Saturday to return to Berkeley in order to hear a panel session that was part of the CS division 30th anniversary celebration. Between the sunny days, the interesting conversations I had with people at the workshop, and some of the work I've done in the past week or so, I feel a renewed enthusiasm for my research -- which is welcome, since I felt uninspired for most of the latter half of February. I spent some time on Monday working on adding support for anisotropic effeects to the thermoelastic element model from last semester. I look forward with unholy delight to adding other physical effects to this element, so that we can add an avalanche of appropriate adjectives beyond anisotropic. Actually, the next effect will probably be Akhieser damping. Huzzah for alliteration! I've also helped analyze and draw pretty pictures of vibrating drumheads; computed frequencies and node points for the third harmonic of a shear-ring resonator; read about thermal effects at grain boundaries in polycrystalline materials; drawn three-dimensional pictures of a building brace structure; and worked out a fluids homework problem involving sedimenting particles. I get to turn interesting physics into interesting mathematics, and solve the resulting problems with interesting computational methods. Huzzah!

• Currently drinking: Lemon-spice black tea