computer science

VMWare trick

From the VMWare ordering site, note the extremely curious wording of the second sentence below:

I’m sure I don’t want to contacted… so I’m going to NOT check the box?  They are doing some neurolinguistic hacking here because I can parse the sentence, but don’t really feel comfortable with its meaning.  Very slimy phrasing.


Computed using python and matplotlib using data parsed from the BBS List.  Assuming an exponential distribution, every year, the odds your BBS would close shop were 0.35 or slightly worse than about 1 in 3.

academia, computer science, science

Turing Complete

Turing Completeness is a concept from CS Theory.  It is an adjective describing the power of a computing system.  If your computer is Turing Complete, then you can pretty much compute (given enough time) anything any other computer can.  I never actually thought it would prove directly useful, only as a stepping stone for deeper theoretical results.  I was wrong.

One of the less glamorous realities of working as a researcher for a financial syndicate is financial software.  Specifically, Trading Software.  These programs are interface nightmares and work to further obfuscate an already incredibly challenging task.  And yet, traders, knowing no better and having no other options, soldier on anyway.  Once in a while, I have to gird my loins, put on my biohazard suit, say a few hail Marys, and plunge into the muck and work with these programs.

You see, my client wanted me to build a tool in the embedded formula language of a financial charting program (which will go unnamed).  For a week I struggled with the program and kept hitting the wall.  Today, while walking to work I actually determined that the embedded formula language of said program I work with is *NOT* Turing complete and incapable of producing this tool.  I couldn’t believe it.  It takes shockingly little for a language to be capable of Universal Computation.  (I did this by realizing the language cannot simulate rewinding the tape and rewrite a symbol, you have to know the sequence of rewinds and the symbols in advance… never mind if this doesn’t make any sense)

Why would they do this?  Because they don’t have the support staff to handle fixing a client’s buggy scripts?  Not a good reason; they already have a disclaimer regarding their limited support with coding.  Ignorance?  Most likely.  There just doesn’t seem to be any reason for this restriction except ineptitude.  This poor design choice has cost the software company many thousands of dollars as we will now have to look elsewhere for a solution to our problem.

Moral:  if you’re going to hamstring your users, let them know you’ve done so.  If you’re planning on building an add-on that gives your users the ability to write code, please  hire someone who has a degree in Computer Science and has taken a class in Theory.  Even the more highfalutin concepts can have practical application!

If innumeracy is the mathematical equivalent to illiteracy, what is the analogue for CS?  Illambdacy?


Random Walks

I’ve been studying finance lately and one concept that keeps popping up is the notion of a random walk. In finance, random walks are used in modeling how prices evolve over time. In the discrete random walk model, an asset price can either go up or down a random amount after a unit of time. Here is a picture of a random walk


The start of the walk is on the left and the path, very random looking, continues all the way to the right indefinitely. Every pixel in the x direction is a time step. Here is a picture with a few random walks superimposed on each other.


You’ll notice that a pattern is starting to emerge.  To better see the pattern, I lowered the transparency of the random walks and ran several thousand of them to get the following image:


Random walks are related to diffusion.  In this picture, the relationship between the two is very obvious.  The idea is that the path of a particle of smoke in air or ink in water is very similar to a random walk over time.  The position of a particle (or price) at a given time can be modeled by a normal distribution whose variance evolves in a manner similar to the continuous of process of diffusion.  So the normal distribution gets flatter and flatter and this corresponds to the dilution of the particulate matter in the medium.

I just wanted to see it.

atlanta, books, computer science, family, friends, games, japanese, science, vancouver


We went down to Atlanta for the break and had a much needed good time.  I spent time with old friends and family.  Old haunts were visited.  Much fun was had.

Every time I revisit Atlanta, which I still think of as home, it makes me a nostalgic and melancholy.  Compared to Vancouver it is dirty, unsafe, badly planned, poorly educated, politically conservative, and in the middle of a serious drought.  But it has a very unique character (outside of downtown).  And barbecue.  Cheap(er) real estate.  Sunlight in the Winter.  My family and best friends live there or near there.  It is older and larger than Vancouver and it has a more extensive rail system that is planning on getting better.  I miss it.

When we returned to our current home with its clouds and cold rain, I realized that I’ll probably end up feeling similarly about Vancouver.

Considerable loot was had this Christmas.  I received a Nintendo DS, which I was secretly desiring for well over a year.  I love classic video games, but it’s makes me feel old seeing all the kids on the bus using styluses to play games and I’ve been wanting to jump in.  Among other things I got a serious rain-coat.  Walking around Vancouver without a umbrella for the first time was liberating.  I may look like, as one friend put it, a yuppie hiker, but screw you guys, I am warm, comfortable and dry!

We also received some very good DVDs, two Miyazaki movies (kiki’s and howl’s) and Bambi.  It is interesting how Eleanor immediately gravitates toward these films.  She will go through periods of liking Disney or Pixar movies, but her interest is never held as it is with Miyazaki’s films.  The exception so far is Bambi.  Eleanor really responds to the young Bambi and the way he learns to walk and talk by listening to Thumper.  I haven’t watched Bambi since I was a toddler, and seeing it with new eyes was actually moving.  I can’t believe how good the character animation is.  On technical achievement alone, the film holds up as a masterpiece.  Quite a contrast to the gutless, schlock sequels that Disney is putting out these days.

Eleanor is different from when we left Vancouver.  Her exposure to her cousins always flips some internal switch in her personal development.  The baby Eleanor is truly gone.  She is a kid now.  She loves painting, books and movies and really likes just horsing around.  I knew every parent thinks and says this, but Kelsey and I got lucky with Eleanor.  She is wonderful.

I’ve kept up with the audio Japanese, but my kanji study has very seriously faultered.  My repertoire is currently exhibiting sub-logarithmic growth.  My goal for 2008 is to finish Heisig and so I need to get crackin on the remaining 1200 characters.  Another goal of mine is to watch something in Japanese w/o subtitles at best once a day, but at worst once a week.  I’m also interested in an SRS system for the Nintendo DS.  I think the best option is Khatzumemo, which can be accessed using the DS browser, however this isn’t too useful on the bus.

This semester is shaping up to be a lot of fun.  I return to research, after a diversion into thesis writing, which is always lots of fun and interesting.  I’m taking a class on dominant eigenvalue problems such as Google’s PageRank algorithm and expanders.   I’m also a teaching assistant for Computer Graphics for the third time.  Computer graphics is cool for so many reasons that I’m happy to have anything to do with it and I hope that doesn’t change.

I have a lot of reading lined up.  I’m currently reading Peloponnesian War by Donald Kagan.  I was always into Greek civilization as a child and I never really understood what specifically happened to them.  Reading this book is like going back and explaining to the thirteen year old still inside me what really went down.  Next on the list are Power Up and The Rest Is Just Noise.

Life is good.  Zero complaints.

academia, food, kanji, vancouver, 漢字


Well, I am now officially a master of something.  It will even be written on sheepskin or some high-quality medium.  The final presentation went well.  I remember falling into a sort of trance as a I rattled off the high-level description of the past year and a half of my life.  The “defense” part of the presentation was painless.  No scary questions or I don’t knows.  It’s over.   Now on to becoming a doctor of philosophy.

Currently no progress on Kanji.  I have been keeping up with practicing the characters I know, but I had so little time while finishing the Master’s that I couldn’t make further progress.  This changes this week as I will make it to 800 for sure.

Went to Kintaro downtown today.  Kintaro is a hand-made ramen place in Downtown Vancouver.  Most of the patrons are Japanese, lending it an authentic feel.  Compared to most North American Japanese food, this stuff is divine.  The gyozas alone were delicious, to say nothing of the rich miso and pork broth they serve.   Some say it is standard fare in Japan, but it is head and shoulders above anything I’ve experienced here.  I can’t wait to try some of the izakaya in the same area.

academia, kanji, 漢字

700 Kanji

Phew.  I made it to 700 Kanji yesterday.  My progress has assumed a logarithmic nature, but this is most likely due to present circumstances.  I submit my final thesis this week and next Friday is my final presentation.  In the meantime it’s been hard to find the time to learn new characters.

Less than two weeks of being a Master’s student left.