Author Archives: Brock Tice

Implementing and Studying the Conjugate Gradient Method

When I start up a simulation on our cluster, I’m used to seeing this after some information scrolls by:

Solver = Conjugate gradient
preconditioner=block Jacobi with ILU(5) on each block

I knew before that this was some way of solving a big matrix representing the problem at hand, but never knew how it was done. (Un)luckily, my midterm project in one of my classes this semester is to implement and play around with the conjugate gradient method. We were given a little introduction to the method of steepest descent, then sent on our merry ways to the Mardi Gras and subsequent break.

I was terrified.

I started reading the course notes that we’re using for the class, but they used a bunch of terminology I’ve never heard of before. They were extremely concise. Attempts at understanding the information on MathWorld and other sites ended in confusion. And then, I came upon this title on google:

An Introduction to the Conjugate Gradient Method Without the Agonizing Pain

With the agonizing pain still acutely in my mind, I clicked on the link and gave it a try. It’s excellent! The author, Jonathan Richard Shewchuk, writes with clarity, knowledge that I’m probably not a numerical analysis professor, and a little dry humor here and there. After searching for him on google, I discovered why the name looked so familiar — I used his Triangle software to generate my 2D cross-section of our model of the rabbit ventricles! The CJ paper has pretty much saved me, and perhaps more importantly has shown me just how cool and clever numerical analysis can be.

If you want to learn about the CJ method, you really must read his paper.

Anti-Islamist Manifesto

I’ve been keeping the political stuff on my personal blog, but this is too important. Via Rantings of a Sand Monkey:

Indland Jyllands-Posten

Like all totalitarianisms, Islamism is nurtured by fears and frustrations. The hate preachers bet on these feelings in order to form battalions destined to impose a liberticidal and unegalitarian world. But we clearly and firmly state: nothing, not even despair, justifies the choice of obscurantism, totalitarianism and hatred. Islamism is a reactionary ideology which kills equality, freedom and secularism wherever it is present. Its success can only lead to a world of domination: man’s domination of woman, the Islamists’ domination of all the others. To counter this, we must assure universal rights to oppressed or discriminated people.

As usual, I encourage you to read the whole thing.

Florida schools choose between bad and worse with new, ID-influenced textbooks

Due to pressures from the Discovery Institute (I.E. creationist propagandists — look them up) the only choices considered were a textbook that flaunts “Intelligent Design” and one that is merely tainted by a watering-down of its coverage of evolution. Fantastic.

Broward selects biology text with watered-down passages on evolution: South Florida Sun-Sentinel

Previous editions of the textbook said Darwin’s theory “is the essence of biology.” In the Broward edition, students will read instead that Darwin’s theory “provides a consistent explanation for life’s diversity.” The county plans to spend $1.2 million for 20,000 copies of the book. It will be required reading in Biology I classes until 2013. “We’re very pleased,” said Rick Blake, spokesman in Chicago for Holt, Rinehart and Winston. “Science is a very strong area for Holt.”

Science was a very strong area for Holt.

ADDENDUM: The ReDiscovery Institute plans to take the success the Discovey Institute in applying Design “Science” to biology, and extend it to other disciplines. They also plan to follow the Discovery Institute’s political strategy:

“Until we gain total control, keep the old testament part of our agenda quiet because it frightens normal people.”

These aren’t the transplants you’re looking for…

A former oral surgeon and his pals were stealing organs from cadavers without consent and selling them for transplant. This is another argument in favor of tissue engineering research — the market really wants more transplant tissue.

D.A.: Body parts case like ‘cheap horror movie’ – More Health News – MSNBC.com

Prosecutors said the defendants took organs from people who had not given consent or were too old or too sick to donate. The defendants forged consent forms and altered the death certificates to indicate the victims had been younger and healthier, authorities said.

…

Prosecutors said the body parts were sold to
tissue suppliers and ultimately used in disk replacements, knee
operations, dental implants and a variety of other surgical procedures
performed by unsuspecting doctors across the United States and in
Canada.


Happy Mardi Gras

This is a synthesis of two recent Mardi-Gras-related posts from my LiveJournal (my personal journal). The first was relatively popular as my LJ posts go.

Happy Mardi Gras
Ahh, even with everything all messed up post-katrina, sometimes I really love this city. Yesterday evening when I was out for my run, I passed some guys in the Neutral Ground on St.Charles, near Louisiana I think, wearing clown outfits with a cooler on wheels and a portable radio. On the way back toward home, I heard the distinct sound of Mardi Gras music as I approached, and one of them held out a strand of beads for me.

“Happy Mardi Gras!,” he yelled happily as I snagged the beads. “Hey, Happy Mardi Gras,” I replied, and went on my merry way, the beads bouncing with each step as I ran.

Some things have changed forever, but it’s good to know that some things haven’t changed a bit.

No bus? I’ll run.
I realized a bit too late this afternoon that I wouldn’t make it to the bus before they shut down most of the route for parades. I took the bus to Napoleon and then got off (as I had to).

Then I started walking on the neutral ground.

Then I saw some people running, and I thought, “you could just run, Brock.”

So I cinched down the straps on my backpack, took my umbrella in one hand and my 20oz diet coke in the other, and I started running. In my 10-year-old $7 sandals from K-Mart. I ran past Fat Harry’s, and I ran past Louisiana, and then I passed Washington and Jackson, and now I’m home. I got a lot of strange looks, and I worry that my calves might hurt tomorrow, but you know what? It actually felt pretty good, sandals or no. It was probably just over a mile and a half, maybe 1.75 or something.

I feel better about not running earlier in the week, like somehow running in normal clothes and sandals with my backpack for 1.75 miles makes up for not running 3 miles in proper attire. I might wander back out there later to catch Muses…

ADDENDUM: By the way, it’s only 5 hours later and my calves are already quite tight from the run in sandals.