Oli thinking outloud

BOINC!

2012-01-02T23:16:00.003+01:00

I decided to try and do something useful with my computer, and set up BOINC so I could choose from a list of projects to use my computing cycles.

Ok, so I just pulled in the debian package with aptitude but after installation then it didn't run as a daemon as the document describes so I decided to run it from the command line. That's where my troubles began.

I understood from the documentation that you could run boinc from the command line and choose some projects to support and voila, everything would be up and running.

What happened to me was that I choose some projects but I didn't get any work to do, my client was querying the projects for work but none was given (sometimes I got a message saying that the project needed x amount of disk space but I had 0 Mb available when in fact I had more then 9 Gb available). I was getting a bit frustrated but decided to try and run the program as a daemon instead.

That on the other hand did work! Now I am happily doing my work and my computer is doing someone else's work for me ;-)

So if you try to run the boinc client from command line as a normal user then it wont work, you have to be logged in as user boinc or run the client as a daemon. At least that's how it works here in debian land.

Ohh yeh, I decided to go with Rosetta@home and climateprediction.net

Something going on in the world of high energy particle physics

2011-06-03T01:01:00.002+01:00

Two months ago there was an article put on arxiv about an experiment performed at Fermilab which showed some strange results. The experiment involved smashing protons and antiprotons together and see what happens. What happened was that they saw a signal that they didn't expect and which supposedly goes beyond standard models of particle physics. This is quite exciting since we are always trying to figure out new ways to learn about nature and the world around us.

I am no expert in particle physics but it seems that this blog post explains what is going on in good detail and hopefully in a manner that most people can understand.

The reason I bring this up now is because back then this signal was not taken really seriously, it was called a 3-sigma event which means basically that it didn't have statistical significance to it, it might just be a fluke. But recently this signal got a 5-sigma significance which is really exciting.

Too bad the Tevatron (which is the accelerator that performed this experiment) is supposed to be shut down soon.

I'm back

2011-06-03T00:59:00.001+01:00

Well, all of a sudden got an urge to start blogging again, don't know why. I will try again now and hope to keep this a bit more updated then for the last three years or so.

High temperature superconductors

2008-12-16T02:28:00.001+01:00

This says it all.

It would be excellent to get easy to produce hight temperature superconductors. High speed railways for everyone!!! :-)

Debian release

2008-12-03T20:18:00.003+01:00

Like Rafael I am becoming a bit frustraded in the release of Debian Lenny. But not because of how long it takes (well, partly of course) but more because of my lack of ability to help :-)

I like to help out in Debian, I have used this system for a looong time now and like to give back some of my time to make it a good distribution. So far I have been focusing on scientific packages like Octave through the Debian Octave Group but I also subscribe to the Debian Scientific Computing Project and Debian Science mailing list allthough I am not an active participant there.

Unfortunately since I began working here in Iceland I havn't given myself time to help out in the Octave group and I was hoping to be able to do some good over the hollidays but due to the Lenny freeze then not much is going on in Debian except bug squeezing and I don't have enough programming experience to do that. So I guess I will have to focus on something else (or perhaps I will begin to make some packages of debian science, lintian clean, that is allways usefull).

Extracting images from pdf

2008-08-10T22:50:00.002+02:00

During my studies I sometimes had to hold a lecture on a certain topic that was presented in a few published papers. When holding such lectures then you really should show some graphs and figures from those papers (don't worry, this falls under fair use of the copyrighted material ... I believe ;) ). An incredibly convenient tool to extract images from pdf files is the pdfimages tool that comes with poppler. All you have to do is issue the command

pdfimages paper.pdf some-prefix

where some-prefix is a name chosen by you and will be added in front of all the image names the command produces. After this your current directory will have all the images in the paper and theyr names will be some-prefix-000.ppm (or .pbm or .jpg but to get .jpg you have to give it the -j option and it won't work for all the images probably, pdfimages -j paper.pdf some-prefix). Then you can import the images into your Impress presentation (I use Impress to make my presentations and then export them to pdf) or use convert to switch between image formats if you are using a presentation software that doesn't support those formats pdfimages produces.

Christian tolerance

2008-07-12T15:02:00.003+02:00

This just hurts my eyes, I just can't stop wetting them out of frustration of the stupidity behind this, whats more if you express your feeling of intolerance towards this then you better prepare for something like P.Z. Myers got in his mailbox, which he shows a few snippets of here, for posting his oppinion of the episode here.

I really do not have anything to add to this, just wanted to point this out to people.

N.B. All the christians that I know are tolerant and intelligent people, but of course its like the saying is, "the empty barrel makes the loudest noise" (which is perhaps why no one hears me ;-) ).

News

2008-07-04T13:13:00.002+02:00

Well, in coming August I am going to leave Denmark after 5 years of staying here. I got a job teaching at Háskólasetur Vestfjarða which is located in Ísafjörður but I will be staying with my syster to begin with. She lives in Hnífsdalur which is a small community 4 km north-west from Ísafjörður, a google maps image is available here.

Atheism: A Rough History of Disbelief

2008-06-23T11:48:00.004+02:00

Jonathan Miller made a very thought provoking 3 episode documentery about the history of disbelief in 2005.

This program can be seen on youtube but it is cut up into 19 small videos and so I am going to list the episodes (I don't like to embed videos here on the blog) here for better access for the reader and in hope that the videos will stay there and not be removed by copyright issues or some other reason:

Episode 1 (named Shadows of Doubt): Part 1, part 2, part 3, part 4, part 5, part 6.

Episode 2 (named Noughts and Crosses): Part 1, part 2, part 3, part 4, part 5, part 6.

Episode 3 (named The Final Hour): Part 1, part 2, part 3, part 4, part 5, part 6.

Enjoy this remarkable series.

The Enemies of Reason

2008-06-23T01:24:00.002+02:00

Richard Dawkins of whom I am a great admirer hosted a two episode documentary about non-science things like astrology, alternative healing and the like called The Enemies of Reason. The shows are available on google video here: Part 1 and Part 2.

Highly recommended.

Developing software using JED

2008-06-08T23:56:00.003+02:00

I am a command line user! Thats that, I don't really like graphical user interfaces. They tend to take up way to much memory/CPU etc etc for my taste (I want to use those for things like music and other things that I need them for when doing my daily routine and I don't want to have many gigabytes of memory installed to do this smoothly, even though memory is cheap today). So I use the command line to do a lot of things.

One of the things I do is edit files, be they text files or program source code files (which are text files, but for this discussion I will make a difference between the a normal text file and a source code file) or something else and I don't want to fire up OpenOffice or some other GUI program to edit a file that is just plain text be they 2 lines or 10000 lines. For this task I really like the small weight editor called JED developed mainly by John E. Davis (hence the name of the editor). This is a lightweight version of Emacs, well it is and it isn't, it has a mode that emulates Emacs and which I use so for me it is a lightweight Emacs editor :-)

To begin editing files in JED it is good to have a quick reference at hand.

The reason I am writing about this editor now is that I would like to get starting to program Octave which is a big project and not easy to navigate through. The program begins in a small file called main.c which does nothing except call another function which begins the main C++ program. Now where is this function located in all the files? I have no idea to begin with so I use a little program called ctags that by issuing the following command

ctags -R *

it creates a file called tags in the source directory which contains a list over all the functions used in the program and in which file they are located (there are dozens of files so searching through them manually is not good and a waste of time when you have utilities like this). When this list is created I can place my cursor inside JED on the function I like to find and press ESC+. (that is I press ESC followed by dot) and I get a minibuffer at the bottom of the screen that asks

Find tag: (default: the_function_that_my_pointer_was_at)

and there I can either type in a name of a function I want to find or it will find the function the cursor was placed at if I just press Enter without giving another function name. This will find the source code file that the function is in, open it up in a new buffer and split the screen of my xterm in two and display my old source file in one window and the new one in the other. To move between the two windows press Alt+x and type other_window, to get back into one window mode typ Alt+x and one_window (TODO, put some nice keyboard shortcuts to these functions).

This function to find the programming functions by typing Esc+. is not on by default, to get it to work you need to follow the instructions of the developer of ntags and put the following line in your .jedrc file

() = evalfile(autoload);

Am I doomed?

2008-06-08T22:43:00.001+02:00

Went for a walk a few minutes ago and came across three black cats on my way!

Does this mean I am doomed and should be writing my will?

Meat and the environment

2008-05-21T22:45:00.003+02:00

Seed has a wery interesting article now about meat and its effect on the global development. An interesting point there is that former largely vegeterian societies like China and India can now afford to become meat societies which is causing quite a strain on their grain production. They can't sustain their meat production and therefore have to import food for their livestock. This in conjunction with ethanol production for fuel puts huge strains on grain production over the whole world which is driving prices of food up which is especially bad for Africa (just saw the movie The Constand Gardener and am therefore a bit sad about Africa at the moment).

Another thing that is interesting, producing one kg of beef takes about 20 kg of grain, one kg of poultry takes about 4.5 kg, 1 kg of salmon takes about 1.4 kg of feed (what kind of feed do they need?). Why not buy fish instead of beef next time you go shop? At least eat more chicken then beef. I love beef, I love lasagne, beef with spaghetti and all kinds of beef dishes, but for the sake of our future we really do have to cut down our consumption of it. According to Seed then the average american consumes 100 kg of meat (I guess that is per year), that is 100/365 = 0.274 or 274 g of meat per day which is a good steak (I just ate a 300-400 g steak just two days ago).

Think about it.

Memory in linux

2008-05-04T20:01:00.001+02:00

Just found a great blog entry about memory usage in linux. I have often wondered about how memory is reported using the free, ps and top commands. This explains it all :-)

An update

2008-03-13T13:37:00.002+01:00

Just had my master thesis talk, it went ok. I had to many slides and was spending to much time explaining basic things like atomic transitions, atom light interaction and some banal stuff like that, should have just focused on the project because I ran out of time (we get 45 minutes here in Copenhagen University) when I got to my experimental results and had to quickly run over those.

I haven't finished my thesis yet but it is close to being finished and I have set a date with my supervisor, the 27th of March which is in 2 weeks so I will be pretty busy finishing that one.

Laters.

Some cool things

2008-02-20T12:56:00.003+01:00

Here are a few cool things I have found during my wanderings over the net lately:

A draft to a paper to be published in Scientific American about the limit of quantum computing.

A blog about cool stuff found on the preprint site for papers on physics stuff.

A blog post about why linux doesn't cut it in the mainstream and an experiment the author is conducting to try to prove his hypothesis (won't be a conclusive experiment, but could give reason to further experiments in sociology :-) )

Solar evidence points to human causes of climate change, take that climate warming by human intervention sceptics! :-)

The most powerful laser ever built.

That all for now.

Retro

2008-02-14T23:30:00.002+01:00

When I was a child my family were one of the first to get a game console!

I was really popular with that, but I have lost track of which game console it was we used to own. All I remember is two paddles that had a round knob on them and we would play games like Pong and other variants of that on it.

But now I think I have found it! Telstar Sportsman (a picture of it is in the second row, third column).

Man that was retro!

odf, xml and the web

2008-02-02T15:48:00.000+01:00

A friend of mine just showed me a use of google-docs where he published an excel sheet inside an iframe.

This made me wonder if it would be possible to implement in browsers a support for ODF files inside of XHTML.

Some browsers already have support for some XML files like SVG, why not ODF as well?

I think it would be cool.

error bars in gnuplot

2008-01-30T21:09:00.001+01:00

I use gnuplot to make all my graphs for my thesis.

Some days ago I decided that it was about time I put some errorbars on the experimental values in my graphs (this is something that is pretty important in physics, and should be in all subjects that handle measured data) so I calculated my standard deviation from some fits I made and used them as my errors.

Now to plot them. Hmmm .. how do I do that?

Well, if you have a datafile called "data" and in it you have 3 columns, the first column representing the x-axis, the second column the data (the y-axis) and the 3 column the +/- error values on the data values in the second column then you just give the command

plot "data" using 1:2:3 with yerrorbars

and you get the data values with the errorbars set correctly.

Except it didn't really plot well for me. The lines that made up the errorbars were dashed in stead of solid when I printed them out into a eps file and if I wanted to have different colors, if they were all red like the default is then there was no problem, but having one data set green and another blue and a function that was supposed to be compared to the data as red, then I had problems.

I wondered a lot about that, tried several other plotting utilities (gees those graphical utilities are bad ... not intuitive at all I think) and went no where. I asked the nice people on the news group comp.graphics.apps.gnuplot and there I was just told to either use the candlesticks mode or define the color by using the linetype option.

So I tried and tried with no luck.

Until finally I came across one sentence there that said in plain text to my question about why the error bars were dashed

That would be because your terminal setting has patterned linetypes (no "solid" option to the postscript driver)

and then it continued on to answer some more questions so this part did not register with me by some reason the first time I read this.

It seems that the default of gnuplot is to set the dash option with the postscript driver when you issue

set terminal postscript eps

So to get a solid line with your error bars in your eps files you have to issue

set terminal postscript eps solid

Took me quite a time to figure this little thing out but should have taken me a lot less time if I had read better what was written to me in that post :-)

Lesson of the day, read what is written for you :-)

GeoTIFF and NetCDF

2008-01-30T00:44:00.000+01:00

A friend of mine is studying glaciology in New Zealand and he is working there with data taken with the GeoTIFF format but needs it in NetCDF to put it into the model they are using at the university so he wrote a little C program to convert between the two using the libgeotiff and NetCDF libraries.

I got permission for him to put the program out on the net for others who are interested to have a look at it and also to put a GPL license on it. You can find it here along with a small makefile to compile it (read the makefile before you try it, it might not work on your computer), or you can just compile it with your own compiler.

At the moment the software is limited to his specific needs but it is well commented so people should not have to much problem in adapting it to ones needs. Perhaps we will work on it more in the future and get it to be more general.

Absurd!

2008-01-22T12:02:00.000+01:00

Ok, a really absurd situation has just arisen here at my floor at the University of Copenhagen in the H.C.Ørsted building. We have a HP LaserJet 4700 printer here on the floor and yesterday a coworker of mine was printing out his Ph.D. thesis and the printer ran out of the magenta toner. Well, we just replace it today he thought and went home yesterday content on continuing the day after.

Ok, today arrives and he contacts the computer people that handle the printers and they tell him that they don't have that color on stock and whats more they don't have the money to buy more cartridges!!!!

WHAT! They don't have the money to buy toners for our printer? What kind of an operation are people running here? :-)

Here is a well respected institute in physics (and physicists print a lot of stuff, we need our printers) and they can't hold our printers running!

Fortunately there are other printers in the building but this is just so typical somehow and demeaning for the institute. I just don't have a word for this.

A bad aspect of the free market

2008-01-17T23:27:00.000+01:00

One of the worst aspects of free markets, like the one in the U.S., Europe and Japan, is that its main propeller is the personal consumption. When the personal consumption goes down then the financial sector is in trouble.

This can happen if the real estate prizes fall and the owners of the estates have mortgages that become less the value of the estates (you have a house that cost you 1 million dollars to buy and you took a mortgage on it to buy it, then the value of the house drops and it is only worth 800.000 dollars) this looks bad in the eyes of the one who gave you the mortgage.

Her is a scenario that could happen:

1. The real estate prizes drop
2. The banks need money to lend to consumers so they can consume as much as they used to before the prizes of their houses went down
3. The banks foreclose on their mortgages and people start loosing their homes

This is bad I think. Of course this is only one scenario, if you have enough money to pay out your mortgage then the bank just takes your money and not your house but most people who took out the mortgages in the beginning do not have that amount of cash lying around so this scenario (which is probably the one that happened now in the U.S.) is worst on the poor, like always when were talking about financial problems, they always hit hardest on the poor.

Wikipedia for experts

2008-01-17T22:20:00.000+01:00

Scholarpedia is a new wikipedia style encyclopedia, or should it be called an encyclopedia when it is not meant to cover everything from the smallest to the biggest?

Scholarpedia is supposed to be a specialized wikipedia where experts in their fields write about the stuff they know about. So it is supposed to take subjects from wikipedia like saltatory conduction and make a pretty in depth article about it by an expert in the field. When the first article is created a curator is nominated for the article and every time someone wants to edit the article the edits go through the curator first and he decides if the edits are appropriate or not. It's not a completely free editing encyclopedia but almost (of course people could get dissatisfied with the curator, how the community of scholarpedia will react to that I have no idea).

Hope it will do good and get more physics articles in there :-)
At the moment it is more focused on computer engineering and biology related articles.

Happy new year

2008-01-17T15:51:00.000+01:00

2008 has come and 2007 has gone!

A little late new years greatings, but better late then never right?

I spent my holidays in Iceland, flew to Iceland on the 18th of December and came back to Copenhagen on the 7th of January. It was nice visiting Iceland once again, seeing old friends and some realllly old friends. You see, I went to visit my brother and sister who live in Hnífsdalur (which is a small village just outside of Ísafjörður) and there I met an old friend who I had not seen in ten, twenty years or so. That was really fun. Now I have him on MSN so I won't loose track of him again.

It is always fun wisiting Hnífsdalur, there is allways stuff going on there if you look for it (or it comes to you). Like bad weathers that you have to fight through (or just wait out, inside with some hot chocolate and other nice things), this time I was lucky enough to get to a blitz tournament in chess (I came in nr. 9 of 14) and see a concert with Dúndurfréttir which is an Icelandic band that plays cover songs by Pink Floyd, Deep Purple, Led Zeppelin and Uriah Heap mainly. Me and my brother went to hear/see them, it was fantastic! I think that The Rolling Stones magazine has said that this was the best Pink Floyd cover band on earth at the moment (completely unsourced statement, just by hearsay).

As for school, well, things are the same there. I am not satisfied with turning in the paper like it is but I don't know what else I can put in it except a few details that I have been meaning to put in it for quite some time but just never had the energy (or whatever one is supposed to call it) to do it. That has to change now.

Enough for now

Climate change sceptics thwarted

2007-11-12T15:58:00.000+01:00

The BBC have just put out a pretty nice listing of the top 10 topics that climate change sceptics have made in the past and the scientists response to them.

Read it here.

I never remember stuff like this, I read it and then I forgett it, and then I meet a sceptic and try (unsuccsessfully) to explain to him why he is most certainly wrong and just end up saying like a complete idiot "your wrong because your wrong" :-)

I should print this out and read it every time I go to bed. Thats a good brainwashing.

Attention span experiment online

2007-11-11T01:54:00.000+01:00

Here is a pretty cool attention span experiment. Just follow the instructions and press start at the bottom of the page when you are ready to begin the test, don't worry, it doesn't ask you about any personal information (the most it can do is take down your IP number, but thats not such a big deal :-) ).

Ran across this while I was reading something about why we forget information and some information we just don't pick up correctly.

Zeitgeist

2007-11-08T14:56:00.000+01:00

Yesterday I came across a movie that is available online, it is called Zeitgeist and is almost 2 hours long but a really interesting watch.

I especially liked the first part about religion and the third part about economy, though the conspiracy part concerning J.P. Morgan and the Rockefellers and all that got a bit on my nerves. The second part about the 9/11 was a bit over the edge for me, there are some factual errors there like that there were 19 people who hijacked the planes but some were under stolen identities which explains why there are some on the old official FBI list of the hijackers who are still alive, I think the FBI have updated the list now. But the part about the buildings and their ability to survive such an impact is interesting, also the part about explosions in the ground floor just before the impact is interesting. The connection made between Hitler and USA is fun also, don't take much notice in it, but it is funny to see :-)

Some funny stuff

2007-11-08T14:42:00.000+01:00

Here are some really funny videos on youtube:

Stephan Lynch is a great comedian, this is a bit on the edge but still funny, recommend all the stuff by him that is under the "related videos" catagory.

Rachmaninov had big hands is a fantastic sketch! In fact everything by Igudesman and Joo is fantastic. Would really like to see their show live.

Not working

2007-11-08T14:38:00.000+01:00

Well, it's not working taking a vacation from blogging to focus on my thesis so I will just continue blabbering like I always do.

Another update, I got neither of the positions I had applied for and talked about in an earlier post. Bummer, but then it is just to apply for something else.

Interpol is looking for a pedophile

2007-10-08T16:15:00.000+02:00

Interpol is searching for this man who is seen abusing young boys on videos. See if you have seen him around your community and contact Interpol if you have, contact information is in the web page about that "man".

A little update

2007-09-28T15:37:00.000+02:00

I am so close to finishing my masters now I think, that I have begun for serious to apply for Ph.D. programs.

So far I have applied for one at DTU, a really interesting project there that is about making quantum feedback controllers so that measurements that have to be so precise that the quantum noise that follows every experiment made is the lower bound of the precision in the experiment. Usually experiments have lots more uncertainty in them, the equipment that is used has some uncertainty but using feedback controllers than you can try to minimize this uncertainty.

The other position is in Stuttgart, in the group of Prof. Tilman Pfau. They are investigating a lot of things but they are searching for a Ph.D. student in their dipolar BEC of chromium atoms. Sounds fancy ayyhh?? :-)

So I am going down to Stuttgart in october and giving them a talk and they will show me around the lab and we will have a little discussion about the prognosis of me being hired in the position .... jaaaayyyy! :-)

So not much blogging going on, but I will update this when I know something about my future plans.

War on Democracy

2007-09-09T13:27:00.000+02:00

A pretty interesting film can be seen here. It is a film by the Australian journalist John Pilger and is about the struggle for freedom and justice in Latin America and the US intervention there. For anyone who doesnt know about the history of that piece of the world this is a good start.

If you have one and a half hour to spare, take a look at this movie, its educational.

Camera

2007-09-01T16:32:00.000+02:00

My father gave me a cheap webcam some time ago and I never got around to setting it up, today I felt like playing around a bit and decided that the camera would be todays victim, and fell it did :-)

Here are the steps I had to take:

Since I am using debian unstable things are a little bit more difficult for me then the average linux user. My first problem was to make sure the computer recognised the camera. I have a USB camera that I had no idea of what kind it was, all it said on the front was "Creative" (which is a company that all computer personal know) but that did not tell me much about what drivers to use for it or anything else. So it is a USB thing, then the command lsusb must show it (just like lspci shows all pci devices) and there it was:

Bus 001 Device 002: ID 041e:4028 Creative Technology, Ltd

ok, it has ID 041e:4028, lets head over to the guy who holds a good list over most of these cameras, a cool french physician who decided to make a lot of drivers for USB webcams in his retirement. There is a table somewhere there that shows all the different types of cameras and what company produces them and some other information. There I found my USB ID under PIXART

Creative 191 0x041e 0x4028 Vista Plus Pac207 Pac207 Yes gbrg spca5xx ****

This told me to use the spca5xx driver so I searched through the debian archive for this driver but all I came up with was the gspca-source package. After a little pondering I finally tossed my eyes over to the download page of the french mans front page and there lo and behold stood "for kernel up from 2.6.11 : gspcav1-20070508.tar.gz
for kernel below 2.6.11: spca5xx version 0.60.00-1:
spca5xx-v4l1goodbye.tar.gz". Ok, I had kernel version 2.6.17-2 (seen by uname -a), so did a aptitude install gspcd-source and read the README.Debian file for this package where it showed how to use module-assistant to compile these modules into the current kernel. I fired up module-assistant but it complained right away that I did not have any kernel headers on my computer that it could compile these modules against. Ok, lets search for my headers

apt-cache search kernel-headers-2.6.17

gave me no result what so ever! Damn.

After searching a bit I decided that these headers were just not available for Debian any more since it is an unstable kernel after all and I did not want to bother putting up my own custom headers (dont know how to do that) so I decided to upgrade my kernel instead.

aptitude install kernel-image-2.6.22-k7

Ok, reboot and problems start, first the aptitude did not run lilo for me automatically so I had to do it by hand after one reboot (should have checked, never trust computer guys :-) ) and tell it to use my new kernel. Then reboot and again more problems, it said it could not find the modules for this kernel and failed booting. Hmmm .. strange. I boot into the old kernel again and check if the modules are there and yes they are

ojs@heima:~$ ls /lib/modules/
2.6.17-2-k7 2.6.22-1-k7 2.6.8-2-386

After a bit of pondering I found that I had forgotten to change one line in my lilo.conf file, I had copy/pasted from the 2.6.17 lines and the initrd line still had the old kernel version, that is changed

initrd=/boot/initrd.img-2.6.17-2-k7

to

initrd=/boot/initrd.img-2.6.22-1-k7

Rerun lilo and the kernel was up and running.

After booting into the new kernel I installed the kernel header files

aptitude install kernel-headers-2.6.22-k7

and after that I followed the module building directions in the README.Debian file for gspca modules. There I noticed that this does actually build a debian package and used dpkg to install that package then, pretty nice if one wants to upgrade later on.

Now how do I let the kernel then use the webcam? For that I have to load the correct module that I just created with the module-assistant, but how do I find it. Well, since it uses the dpkg to install the modules it is no problem

dpkg -L package_name

shows all the files installed by that package and it installed only one module, gspca.

modprobe gspca

worked like a charm and then I all of a sudden had a working camera! The camorama program all of a sudden started showing a picture of me in front of my computer looking like a ... well, not gonna tell you.

That was that, now I have a working webcam, what to do with it I have no idea, thought about taking some pictures out of the window to show to friends and family from around the world but I dont think it can handle that, at least it gets all blurred and crazy, perhaps I just have to fiddle around with some settings.

This took me a while, about 20 hours, but in the meantime I slept for 8-9 hours, ate a lot, got a haircut, watched TV, procrastinated and tried to figure out how to use POP access to my gmail account (will blog about that later when I have completed that step).

Bill Bryson

2007-08-21T00:31:00.000+02:00

Just finished Bill Brysons book A Short History of Nearly Everything. I really liked it, gave a good overview of its subject, not to detailed so they layman looses interests but enough to keep the scientist interested in the history part of it. As for my own preferences I liked the part about life, I dont know much about biology so that part was really fun for me to read.

I recommend this book for everyone.

Watch your linux box

2007-08-20T01:28:00.000+02:00

Here are some really powerful one liners that one might find handy when taking care of a linux box, be it a server or just your own box.

An inconvenient truth

2007-08-07T00:24:00.000+02:00

Just saw this film for the first time, pretty good film I think.

For those of you who haven't seen it and don't know much about global warming, then you should take a look at it, and even if you know a little about global warming you should take a look at it, it is a good gatherer of facts (has a few political issues in it, but what do you expect?).

There were a few things in there that I did not know before, some minor details like the investigation that Dutch scientists made into birds hatching their eggs and caterpillars coming out for the summer, it seems that the caterpillars are coming out earlier each year, they used to come out at the same time the chicks hatched and provided a good source of food for them and now are too big or something for the chicks to eat, at least some bird species seem to be suffering from lack of food in Holland (and this can be attributed to global warming since the caterpillars get out earlier because it gets warmer earlier).

Anyways, if you haven't seen this film, go see it, rent it or something, download it from Bittorrent, do whatever, just see it.

Two dead directors.

2007-08-04T13:57:00.000+02:00

This week two great cinema directors died and one I had never heard of before. These were Ingmar Bergman and Michelangelo Antonioni, the latter is the one I had never heard of before. I have not seen many of Bergmans movies, perhaps only 1 or 2 but I have seen many movies that have been inspired by him and I am sure many movies I have seen have been inspired by Antonioni also, just didn't know it. I allow myself to call them great even though I don't know their work is because they have been inspiration to great directors like Woody Allen, Stanley Kubrick and others that I think are good directors, so their inspiration must be good also doesn't it?

The reason I like these kind of movies much more then movies like Die Hard 4 or The Simpsons is the same reason I like the lyrics of Leonard Cohen, Tom Waits, Nick Cave more then the latest R'n'B/Hip Hop lyrics (beside the fact that most R'n'B/Hip Hop music is just plain boring) and that is that one takes on the hardship of life, tries to categorize it and find some kind of resolution to life and does it in an intellectual manner, the other perhaps tries but fails in a miserable way. Don't get me wrong, entertainment is ok, but that is all it is, just entertainment, doesn't have any substance but the former artists are good at combining entertainment with social issues and a little philosophy, that is good art in my opinion.

Anyway, solong and thanks for all the fish (ehh .. movies), Bergman and Antonioni.

Learn your geography!

2007-08-03T20:15:00.000+02:00

I see this quite a few times. Some people actually don't know that Iceland belongs to Europe!

The latest I have noticed is on the web of the BBC it self. They should know better. Have a look at this flash animation and hover your mouse over Iceland and see which continent is highlighted along with Iceland.

The war in Afghanistan

2007-08-03T03:04:00.000+02:00

Well, some people are not afraid to cause a stir I see :-)

A very interesting piece he got published in Daily Mail (not a really respectable piece of tabloid that is I am afraid) and is published on his site here.

There he points out the most ironic fact that Afghanistan decided to act up on international aid efforts advice and stop exporting raw material and start processing it and then export it. That is, they have started exporting heroin instead of opium. Nice work NATO! :-)

All jokes aside then he has some real issues there in this piece, the first being the government of Afghanistan. He sees it like that at it is being run by a good man that has no powers. The head of the armed forces is a known drug trafficker that the west (and Russia) lets him do what he has to do to get richer under the protection (indirectly of course, the war on the Taliban in Afghanistan is a part in this and while NATO forces fight the Taliban the drug lords can make their opium and process it in peace) of the NATO forces, and all the other drug lords get the same indirect benefits of course. He also links the death of Litvinenko to this matter.

I dont know what he wants NATO to do differently, he seems to want them to get out of Afghanistan and let them get back to their old habits of fighting each other until the drug lords are so blown apart that the Taliban can come back and take control. I dont like the smell of that one bit, but the present situation does not seem to be any better either.

Haiku-os on Debian

2007-08-02T14:36:00.000+02:00

Cool, just got Haiku-OS running under QEMU. All I did was install QEMU by aptitude install qemu and then downloaded one of the Haiku-OS hard drive images from here (download the one that has the latest date on it and ends in raw.tar.bz2) and then just lunch it with qemu -hda haiku.image and voila you should be up and running.

One minor snag I ran into, my keyboard doesn't work inside QEMU ... have to find out what that is all about.

"If I wasn't Muslim"

2007-08-02T02:08:00.000+02:00

This video makes a good point.

It is exaggeration of course but still has a valid point, Muslims are not excepted by default in some places here in Europe just because their Muslims.

UTF8

2007-07-31T03:00:00.000+02:00

I just switched my linux machine over to the utf8 charset. My first problem was that now when I ssh over to another host to check my post, and that host is using latin1 then those characters specific to latin1 get all mixed up.

Enter luit to the rescue!

Instead of saying "ssh username@host.com" then you say "luit -encoding iso-8859-1 ssh username@host.com" and voila, everything is fine. Of course you dont type this all the time, you make it a default alias :-)

Another problem is that many files on my system are still in the latin1 encoding, then iconv is the thing to solve my problems. Take the file and run "iconv -f latin1 -t utf8 filename" and it will spit out the contents of the file but in utf8 encoding instead of latin1.

XHTML

2007-07-29T01:01:00.000+02:00

One thing caught my attention today about the use of XHTML. The standard says that these kind of web pages should be sent with a MIME type set to application/xhtml+xml but today most web programmers send it with the normal html mime type of text/html. This you can see by looking at the source of the web pages and in its header there is usually something like the following code (this one is from wikipedia.org):

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"
dir="ltr">
<head>
<meta equiv="Content-Type" content="text/html; charset=utf-8">

This says that the document is an XHTML type document but it is sent as a text/html instead of application/xhtml+xml and according to this discussion can even be harmful to send it like that. So what is it that happens when a browser views a XHTML document sent as a text/html? Well, it basically treats the document as a normal html instead of XHTML so the troubles that the programmers have gone through to make the document XHTML complient were all in vein and all the XHTML advantages cant be used.

Why is it important? An example is this text. The Safari browser supposedly (I dont have a MAC so I cant test this) cant display this simple text because it contains XHTML code in it and Safari trying to be more clever than it is says that this is an XHTML document (which it isnt, it is just plain text) and then it sees code there that is not XHTML and like it is supposed to do, it doesnt display this page (if a browser gets code that it thinks is XHTML and it doesnt understand it then it is supposed to not display the page).

Another thing is that Internet Explorer doesnt know what to do with application/xhtml+xml. The product of one of the richest company in the world doesnt know what to do with a simple mime type, what are they using all their man power for? Ohhh yes ... now I remember, law suits! :-)

I think the main point of this rant here is that I think web developers should not start using XHTML at the moment, I dont think the browsers are ready for it.

BeOS

2007-07-26T17:26:00.000+02:00

I am just really impressed over this video. My desktop is really slow compared to this, when I have firefox open with more then 5 flags then it starts getting pretty slow, and things like a javascript at ruv.is can make it really really slow.

Would like to try out the open source version of BeOS, Haiku and see if theyr desktop is as snappy as the BeOS was.

24 hours

2007-07-26T01:17:00.000+02:00

Why are there only 24 hours in a day? Why do we need to sleep?

I cant do everything I want to do in a day in only 16-17 hours!!!! The day is to short!

Today I went to school, sat in front of the computer and tried to write (nothing came out), came home and watched a little TV (the good old Die Hard movie, the original) then want to read a bit on the web but there is just too much to read! This damn web! It takes too much time away from me!

The human rights of property

2007-07-08T14:32:00.000+02:00

Was listening to my Sunday show about the future of democracy. There was this man talking about the right to ownership. Now I am an old socialist and have never thought much about the right to ownership, yes, people could own their house and their cars etc etc, but the right to do this was never really high on my agenda. But he was talking about this right and its connection to democracy. He quoted the economist Hernando de Soto who basically is saying that people wont be good participants in a democracy unless they own something. This I think is a pretty interesting point, can you make good decisions about yourself and your society if you don't have anything to loose?

This I relate to a study that was shown in the film The Corporation where they said that a corporation behaved like a psychopath based on the behavioral pattern of many corporations. Now the step from the ownership to corporation is a bit of a step but I think the first incorporates the other so I don't know what to think about this, one the one hand it seems logical what de Soto is saying but on the other hand experience about corporations and when people hide behind the legal document to make their decisions (that is the responsibility of the decision does not lie with the decision makers directly, but goes through the corporation) is a bad one. Is it possible to make a working system out of these two and at the same time ensure the well being of the whole?

Gulf War 1

2007-07-05T23:23:00.000+02:00

Once again todays episode of democracynow.org gets me in a mood to ramble.

Today they had Joseph Wilson, former Deputy Chief of Mission in Iraq, when the Gulf War started in 1991, and husband to Valerie Plame, the CIA operative whose name was disclosed to the press as a CIA operative (which is a federal crime in the US).

He said a lot of interesting things and an rush transcript of the interview can be read here.

One of the things that caught my special attention was his talk about the buildup to the Gulf war. There he said, quote "he told me that if we did not challenge his conquest of Kuwait, then he would give us all the oil we wanted at a good price, he would serve as America’s policeman in the region, and he would not go on and invade Saudi Arabia".

Woooow ... what an offer ... how could they refuse? Well, I don't know what it was but instead of saying "hey, that sounds good, lets be buddys" Wilson said quote: "Get out of Kuwait, allow all Americans to leave the region, and quit looting American diplomatic properties in Kuwait”, and when that didn't happen they rallied up the UN and launched an attack to ... uhh .. well, to do what? No one really knows by now, but the official story is I think that they wanted to drive Saddam out of Kuwait and help an uprising in Iraq oust Saddam (not the Bath party, just Saddam).

Well, one out of two ain't bad right?

I find this interesting because one of the conspiracy theories about the Gulf War was that the US had turned a blind eye to this invasion to begin with, which is perhaps not so far from the truth considering that the meeting between Wilson and Saddam happened 4 days after the invasion. Well, the conspiracy theory can be read here. Guess I should stop listening to these conspiracy pranksters ... but they are just so much fun! :-)

But this thing about Libby ... what a disgrace I would say. If you listen to what Bush says about why he decided to commute his sentence: "I took this decision very seriously on Mr. Libby. I considered his background, his service to the country, as well as the jury verdict. I felt like the jury verdict ought to stand. And I felt like some of the punishments that the judge determined were adequate should stand. But I felt like the thirty-month sentencing was severe and made a judgment, a considered judgment, that I believe is the right decision to make in this case, and I stand by it.". Well, like we all know then the president relies a lot on his gut feeling in decision making. How good his gut is in making decisions is controversial. I for one don't care for it one bit.

Roskilde festival

2007-07-05T17:32:00.000+02:00

It is raining a lot today here in Copenhagen. And I am sitting at home doing my thesis and being quite satisfied about not being at Roskilde festival :-)

I phoned a friend of mine yesterday who is over there to warn him about this rain, he said his campsite was still dry but more rain would flood them ... I think they are flooded by now ... poor bastards.

Violence begets violence

2007-07-05T14:55:00.000+02:00

Once again some people take up the completely wrong reaction to an incident. After the Virginia Tech Massacre there are actually people in the US that still say that more guns are better.

When will those people learn? I hope for the US sake that they are a minority and that the rest are levelheaded enough to outvote them.

Debate

2007-07-01T13:39:00.000+02:00

I was listening to a very interesting radio show about democracy. In it an icelandic philosopher came up with the difference between two words, "kappræða" and "rökræða". These two words have the same english meaning as I can tell, and that is "debate". But he made the distinction that "kappræða" was when two opposite sides met and discussed about one matter but they each had a side to defend and were not there to compromise on the matters but to get others to see their point of view as opposed to "rökræða" which means that two sides meet and discuss until they have digested the problem and perhaps found a compromising solution to it. This distinction I find interesting, where the former meaning is what politicians usually participate in and the latter is what I would call the sensible man participates in. The former has its merits, as for instance when candidates to a post meet and try to persuade the voters to vote for them. Then they have to get their points of view forth and let people know what they stand for and what they see is wrong with the opponents view, but we have to then take this "debate" as it is, as "kappræða", not "rökræða".

I find myself taking this "kappræða" point of view way to often, unfortunately (and I know people that do it to :-) ), have to try to stay out of that, it doesn't lead to anything when you don't have any audience to persuade :-)

News from Denmark

2007-06-28T19:29:00.000+02:00

I was reading the edition of Nyhedsavisen from 22 of June and there was a long piece about two doctors who had been consulting the government on what medicine to use for arthritis and they were apparently taking payments from a company who made the medicine while they were at the same time consulting on what medicine to use. Clearly a conflict of interest. Interested, read here.

A watchmaker was robbed a few months ago but he defended himself against the robbers (who had guns) by using his own gun, which was not registered. He fired 3 shots at the robbers (who fired no shots I think) and wounded one of them if I remember correctly and one of the shots was fired as the robbers were on their way out of the store. He had been robbed several times before and was getting sick and tired of it so he decided to take matters into his own hand an got himself that unregistered gun. It is that sentiment, "taking matters into his own hand", that got the authorities here worried. So the watchmaker was charged for assault and possession of an illegal firearm because there are some that don't want this society to become some sort of a wild west where a lot of store owners have firearms in their shops. Well, today he got acquitted of the assault charge but got 6 months in prison for the possession. The court thought it apparent that he acted in self defense and had thus right to his actions, even the last shot was justifiable.

The danish forces in Iraq use interpreters to communicate with the local folks and these people are local folks who know english. This month it got released to the press that two of these men had been murdered because they were helping the coalition in Iraq. This got people worried about the other interpreters that are still alive. Today the government announced that they will help these people by either giving them citizenship here in Denmark or a bag of money so they can start a new life in a neighbouring country or somewhere else in Iraq.

Amazing harassment

2007-06-20T23:00:00.000+02:00

Óskar pointed out to me a news show from Democracy Now which is aired once a day from an abandoned fire building in New York. It is a one hour show with short news in the beginning and then it seems to have an in depth interview for about 2/3 of the program. I have only heard two shows so far so I cant say what the norm is for them.

The show today had an interview with Josh Rushing who got famous from the movie Control Room when he was the press office for the US Central Command. If you have seen this movie then you might remember him as being the only american officer who had any doubt what so ever about the policy of the US and how they were treating al Jazeera. In this interview he describes how he quit his job for the Marine Corps and took on a job with the English speaking al Jazeera. Good for him, hope he helps in making both worlds understand each other.

What amazed me most about this interview was his description of one of his first assignments for al Jazeera. He wanted to do a piece on a small town in US and give a portrait of the life there. Now when he got there the local news got interested and had obviously only heard that there was a reporter from al Jazeera coming because the reporter from the local newspaper thought he would be arabic and wearing his cape and turban or whatever! When they met the local reporter got pretty interested in Rushing's story and did a good interview with him. Rushing did his piece on the town, went back to Washington and end of story.

Not quite, later Rushing got a phone call from this reporter saying that after their meeting a federal agent (forgot if it was FBI or NSA) had contacted her and made several questions about the meeting with Rushing and some subtle threats also if I remember correctly. Later Rushing also found out that almost no one in the town wanted to speak to him again because of this agent who had obviously spoken to everyone Rushing had spoken to during his reporting on the town. This was probably for the same reason that the local news reporter was afraid to call her mother any more because she thought by doing that she would be adding her mother to some black list with the federal government! COMON! Afraid to call your mother because she might be black listed because you spoke to an american citizen who happens to be working for the English version of al Jazeera!

Wooohaaa ... I just cant stop being amazed by all these stories that are coming from the US at the moment. I mean, they have always been a protective society since the commie scare and high surveillance has been common even though people didn't know about it but nowadays it is just becoming really crazy. Poor bastards that live over there. My sympathies :-)

Democracy

2007-05-30T18:02:00.000+02:00

I just saw that George Bush had nominated Robert Zoellick as the next president of the World Bank. Wait a minute, whats wrong with that picture? A single man who represents only one country nominating a man in the governing post of a world institution and it is taken for given that this man will become the next holder of the post! Yeah, thats how things are done in world politics, this is the way it has been and will always be it seems. But this got me thinking about democracy and playing along with it. Inside nations than we often democratically elect our leaders to do the governing job for us. And they decide to do something like have free dental care for children, or free daycare for low payed employees or better medical care for all etc etc, something social that affects many of us but not all. Then the strongest of us often cry out and say they wont take part in this (ok, usually it is not something obvious like the points I talked about earlier, usually something obscure like welfare for drug addicts or other social outcasts that could make their own living) and if the rulers intend to carry on with this then they will take their business elsewhere and leave the rest in the dirt forcing the government to retract their plans. This is what I tend to see with global politics also, and I think it is rotten. This is specially clear with USA, they do this often and the other countries can hardly do anything since USA is such a strong economical power. I have no doubts that other countries would do the same if they could, but just don't have the economical power behind them to do so. I do think that EU has the power but just hasn't used it in a highly public matter or then at all.

But I don't know, when I am forced to pay license for the internet connection here in Denmark that I don't use to watch TV (the reason the danish government is making all of its citizens pay license for its internet connection is that they have started sending out the public TV for free from the homepage of DR and it is viewable only to computers that have a danish address) then I would comply if I thought it was just for a student to pay this license, even though I did not enjoy the benefits from it, just because it is an (almost) democratic consensus to do this and I have to play along since I am a member of this nation at the moment. USA does not see it with the same eyes and I doubt that the rest of the world does either.

Panorama and The Church of Scientology

2007-05-19T14:14:00.000+02:00

Well, it seems the Church of Scientology is at it again. I ain't no big fan of them, in fact quite despise them but still in order of religious tolerance then I tolerate them. But I do like their antics from time to time, like the ruckus about John Sweeney's momentary laps of reason.

The whole shabang started by The Church of Scientology posting a clip of the incident on youtube where you can see that the two men are in a sort of a shouting contest and Sweeney taking it way to far but still gathering his composure in between to ask if Tom Davis understood him. It is not clear from the clip what interview Sweeney is talking about but reading the transcript from the Panoroma show (viewable here) shows that Sweeney did an interview with a man named Shawn Lonsdale and Tom Davis came in while Sweeney was doing the interview and discredited Lonsdale and not allowing the interview to continue by interrupting it the whole time, Davis accuses Sweeney of being partial against The Church of Scientology but Sweeney insist on that Davis does not know what he is talking about since he did not see the beginning of the interview and the shouting contest begins.

There are other griefs Davis has with Sweeney, the first youtube post is only 1 of 2 they have on him, the other is when John Travolta comes to some cinema to do a promotion for his newest film and we see Sweeney in the crowd shouting out "questions" to him, watch here. Now this does not give a good view of Sweeney who I think is a good reporter in general and so does the BBC by the look of it, see the take on it from the BBC themselves here.

But judge for yourselves, watch the Panorama flick, read up on The Church of Scientology, have a look at what people are saying who are not stars and have wandered away from the congregation.

I for one think that a reporter looses composure and is followed through the taking of his documentary is not a good start for a documentary, but there are other things in there that are worth while. The following and all the interaction between Sweeney and Davis goes to show a pattern surely but is it really fair to judge the whole of Scientology from how Davis is? Its the same as judging the whole of BBC by the way Sweeney is.

Beautiful song

2007-05-17T21:08:00.000+02:00

I was watching Hable Con Ella (Talk to Her) the other day, a very nice movie but one of the strongest scene in that movie is when Caetano Veloso sings Cucurrucucu Paloma. A definite favorite of mine at the moment.

Gaussian cooling

2007-05-15T16:18:00.000+02:00

In my experiments at school I do laser cooling of Mg atoms. For this we use a Gaussian beam (that is a beam that has the intensity shape of a 2D Gaussian in the direction of the beam) to get a good distribution of light on the atoms. But I wonder what would happen if we had non-Gaussian beams? See the pictures here to see how Gaussian and non-Gaussian beams look like (the Gaussian beam is the TEM00 one).

Subfigures in LaTeX

2007-05-14T17:49:00.000+02:00

There is a "new" package in LaTeX that is called subfig, which handles multiple figures all lined up nice and clean. Before there was the subfigure
package but that is no longer in development and is being replaced by subfig.
The only difference is that instead of saying something like

\begin{figure}
\mbox{
\subfigure{\includegraphics}
}
\end{figure}

you say

\begin{figure}
\mbox{
\subfloat{\includegraphics}
}
\end{figure}

and notice that the two brackets there don't have to be but it gets pretty ugly if their not, they represent the text that comes in the List-Of-Floats (LOF) and the caption to the file respectively. If only one [] pair is given with text in them then that is the caption to the figure and that text also appears in the LOF, if two brackets are given then the first one will be the LOF (if empty then nothing is printed in the LOF.)

Notice allso that the subfig package calls the caption package I talked about earlyer so defining the caption package again in the preamble will cause an error. Use the \captionsetup command instead to set the caption options.

So to put up 4 figures in a 2x2 formation you would do something like this:

\begin{figure}[htbp]
\begin{center}
\mbox{
\subfloat[][caption1]{\epsfig{figure=figure1.eps}}\quad
\subfloat[][caption2]{\epsfig{figure=figure2.eps}}
}
\mbox{
\subfloat[][caption3]{\epsfig{figure=figure3.eps}}\quad
\subfloat[][caption4]{\epsfig{figure=figure4.eps}}
}
}

Read the subfig.pdf file in the ctan directory for this package for more information.

Michael Franti

2007-05-09T01:41:00.000+02:00

Check out this guys music, listening to him on the radio at the moment, pretty groovy stuff :-)

captions in latex

2007-05-09T01:38:00.000+02:00

People doing their thesis in LaTeX should use the caption package to customize the caption text belove floats like figures and tables, it looks much nicer since the default caption format that comes with latex is really bad. Read the caption.pdf file in the above directory at CTAN for an introduction to the subject.

Nikola Tesla

2007-05-07T02:43:00.000+02:00

Nikola Tesla is often described as an unsung hero or prophet of the electrical age. It is thanks to him that we have gotten so far in our modern day use of electricity, he is a true pioneer in that field, no doubt about it.

Evidently some people think that his story should be told and he did write down some notes about himself that were published in the volume "My Inventions, The Autobiography of Nikola Tesla" which is available for free here. Another that thinks his story should be known to more people is Margaret Cheney who has written a book about him called "Tesla: Man Out of Time".

Both of these are on my reading list now which is getting waaaayyyy to long.

Getting rid of loops

2007-05-06T17:08:00.000+02:00

Programs like Matlab and Octave have problems in doing loops while running user made functions. So it is best to avoid them as much as possible. One simple example is multiplying every element in a matrix A by a corresponding element in matrix B, this could be done by the following loops

for i in [1:size(A(:,1))]
for j in [1:size(A:,2))]
C(i,j) = A(i,j)*B(i,j);
end
end

Now, this would take a long time to run if A and B were really big matrixes (like millions of elements). But if you use the inherent multiplication rules in the programs, something like

C = A.*B;

then this calculation only takes a few seconds.

A friend of mine had a problem the other day where he thought he could not get rid of the for loops and his calculations were taking to long and he didnt even have the patience to see them finished (he was thinking about doing them in C++ or fortran instead) but having a one night look at the problem I found out that his problem could actually be solved a lot faster by using algebraic notation.

His problem was that he had 4 loops, 2 loops to go over each element in a matrix A and two loops to go over a certain amount of neighbors to that element in each of the mentioned loops, something like this

for i in [1:size(A(:,1))]
for j in [1:size(A:,2))]
sa = something1;
sb = something2;
ta = something3;
tb = something4;
for k in [sa:sb]
for l in [ta:tb]
Z = f(i,j,k,l);
end
end
end
end

Now this was a lot more complicated and the function f(i,j,k,l) had a nonlinear factor in it so at first I thought it wasnt possible to simplify this but I was proven wrong fortunately :-)
The trick was that functions can take matrixes as input in Octave and by using the . operator they perform the function on each element in the matrix and not on the matrix as a whole, like is the difference between A*B and A.*B in matrix notation, the first multiplies each column with a row in the other matrix, but the latter multiplies each element together. The same can be done with nonlinear operators like the power operator ^
So for loops like is above where the function is Z = 2^(sqrt(A(i,k)^2 + A(j,l)^2))) can be simplified by using the meshgrid command

x = [sa:sb]
y = [ta:tb]
[X,Y] = meshgrid(x,y)
Z = 2^(sqrt(X.^2 + Y.^2))

does the same thing except much faster. I didnt manage to get rid of the first two loops but he says that his runtime went down from infinite to about 5 minutes, thats pretty impressive I think.

Hope this can help someone who is learning Matlab or Octave

MathML

2007-05-03T04:31:00.000+02:00

Was fiddling around with MathML this night and just could not get it to work correctly for the servers I have access to. I can make my own html files on both klaki and my school and tried both of them (see here and here for the results) and both of them gave out the wrong Content-Type so that firefox did not recognise them as xml files and displayed them wrongly. My solution was to put a .htaccess file in the directory with the files where the content was just

AddType application/xhtml+xml xhtml xht

This tells the apache web server that each file with the extension xhtml or xht should be sent out with the Content-Type application/xhtml+xml.

For those who have no idea what I am talking about then with each web page that you fetch from the net then there is a little header that you dont see and in that header there is a line of the form

Content-Type text/html

if the file is a normal html file. This line tells the web browser what kind of file he is looking at and then the web browser decides what to do with the file based on this information. Firefox relies solely on this line but IE looks into the content of the file and tries to guess what kind of file it is. So if this Content-Type is wrong for a xhtml file then Firefox does not display it correctly which was happening to me so I had to make the servers on those machines send out the right Content-Type so that my browser would know what to do with them. Since I dont have administration right to neither of those servers then I had to do it on my own work space. Apache server has this .htaccess file that overrides the default server configuration (if that is allowed by the administrators that is).

Pretty nifty ayhh?

I like this mathml idea, this could lead out to better math publishing on the net, with the use of SVG and mathml then science authors would not need to publish using pdf anymore and the user would not have to have a pdf viewer on his computer :-)

Unfortunately then IE does not provide support for mathml yet, but there are plugins available for it that can let you view such files. Firefox has builtin support for mathml.

Hilarious!

2007-05-02T14:21:00.000+02:00

Now this is really good stuff! For those who are not to good in their English with a heavy Irish accent then this little girl doesn't like her school and wants it knocked down or blown up and is calling a demolition company in Dublin to do it for her. Hear the demolition guys response, how else would you react to a request like this?? :-)

Richard Dawkins

2007-04-22T15:34:00.000+02:00

I am a great admirer of Richard Dawkins (official homepage here) but when I listened to his talk at the TED conference I was finding myself to disagree with him on his final point of being a more militant atheist. Dawkins is most famous for his anti religion stanz and his fight against creationists and intelligent design which I wholeheartedly agree with but in that talk he said that we atheists should stop being so damn tolerant and be more militant in our views. I interpret that in that way that we should start to be some kind of missionaries for atheism (or agnostic, whichever you want to call it) and try to convert believers into non believers. No thank you very much, I say let the people have their own faith in private. But I do agree in the way that we should not be shy about it, we should talk about our atheism and if people are willing to hear it explain why we don't believe. If we don't then religious people will dominate the discussion and "uninformed" people will hear just the religious point of view which is not good, there has to be a counterweight.

By the way, at TED there are a lot of nice talks (and not so nice, its a matter of personal taste and what you think is interesting), so if you find the spare time, have a look at a few of them.

perspective

2007-04-13T02:59:00.000+02:00

It is funny to be a physicist and work with atoms. There you have to think in the nanometers scale. This sort of got me off balance when I was looking for bed linen. I measured the cover of my cover to be 2 m long and 1.2 m wide and went looking for that but found only 2 m long and 1.4 m wide! That is a 20 cm difference! That is huge I thought, the linen will be hanging around my cover and it wont be comfortable. I searched in many places but all had the same sizes. I started to get suspicious of my doubts and decided to contact my sister who is a professional seamstress. She just laughed at me and told me that this was normal and that I should go get a reality check (ok, you didn't say it in those words sys but close enough :-) ).

Yeh, mixing work with every day life is difficult, work makes sense, life doesn't!

New debian release

2007-04-11T17:23:00.000+02:00

Seems that Debian (the linux distribution that I use) has released their newest candidate Etch last sunday and I first noticed today! Shame on me!

But it doesnt really matter to me, I use the unstable version of Debian (find the stable version uses to old versions of software since it is rock solid and is primarily made for servers that dont need graphical user interfaces and some other user stuff that the unstable version provides) and the releases have little effect on that version, but it is allways fun to see Debian reach a goal.

gmail and firefox

2007-04-10T21:39:00.000+02:00

I use gmail now for my mail, and firefox as my main web browser. One thing that I like about firefox is its ability to have multiple tabs open and save them when I exit it and reopen all my tabs when I open it again so I enter my browsing experience just like I left it. But it is slow on an old computer like mine is (I only have 256 MB of memory which I think is the important factor here) so I try to keep the flags to a minimum (I usually have about 10 open though between sessions). One flag that I always had open was my gmail but not any more after I found this extension to it. Now I have a little gmail notification at the bottom of my browser and a number behind it that tells me how many mails I have unread in my mailbox, pretty nifty.

Chrocheting for peace

2007-04-10T03:06:00.000+02:00

Hanne Gaard Grønlund (only in danish but have a look at her gallery) is an artist that chrochetes for peace by making hand grenades, bricks (like youths used in the recent Copenhagen riots), guns and blast belts out of yarn. She has an exhibition I think in Charlottenborg art gallery, really have to go and see it soon.

Natural Capital Institute

2007-04-07T03:02:00.000+02:00

This looks like an interesting institute. Wish I had the time and qualification to help out on that one. I think information like that is needed.

Idea!

2007-04-04T16:49:00.000+02:00

Now, I dont know if there are mobile phones that do this but would it not be nice if you could use your mobile phone as a PDA but using voice to record your memos instead of writing them down? I remember it was popular at one time to have small tape recorders with you and record ideas and dictates at the time it was convenient, I think it would be nice if your mobile phone could do that. I for one am allways forgetting things and even though I dont have a mobile at the moment I would like one where it would be easy for me to record short messages that I would keep formyself to remember. Perhaps the interface could be designed so the user would only have to push one button (a shortcut) to start recording and after recording a dialogue would appear that would ask you what you would like to do with that messages, store as a general message or put into a calander and make a reminder out of it ... or whatever. Im gonna patent the idea! NOT :-)

RÚV is modernising

2007-04-01T12:15:00.000+02:00

RÚV (Ríkistútvarpið) is the government radio in Iceland and is slowly modernising itself, the latest effort is the podcast. So Icelanders at home and abroad, go knock yourself out. To bad it requires iTunes which doesn't run on linux :-)

Interesting

2007-03-18T22:33:00.000+01:00

Here is a site that shows how people can help in "saving the world" just from the leisure of their homes in front of their computers. But then again doing that costs electricity which is energy and that is most certainly pollution (unless you have hydro power or something like that), what a predicament! :-)

Nice picture

2007-03-15T00:32:00.000+01:00

I like this picture. It shows how the Cassini spacecraft saw an eclipse of the sun behind Saturn. Higher resolution pictures are available to the right of the picture. If you look at one of the higher resolution picture then you can see a small dot to the left above one of the main rings, that is our little earth.

One million quid!

2007-03-10T01:10:00.000+01:00

I don't think I would be able to do this. Some would say it is just paper ... is it?

Crazy guys I would say, but then again I am just a material boy.

Aluminum

2007-03-05T22:36:00.000+01:00

Earlier this evening I heard a radio show from back home in Iceland where there was a person who said that it did not pay for the environment for Iceland to produce electricity for aluminum factories because it took so much power to move the bauxite (the ore that aluminum is finally extracted from) to Iceland and then move the final product away from Iceland again.
Now this is something that I can relate to but is it true? Alcoa says it can produce 1 ton of aluminum from 4 tons of bauxite and it takes about 15 kilowatt hours to produce 1 kg of aluminum according to wikipedia. So to produce 1 ton of aluminum with clean energy in Iceland it costs 15 megawatt hours and lets say that if it was produced by unclean energy in the country of the mine then the difference should just be the transport of the bauxite and aluminum. So for this to be economically and environmentally viable then it cant be more expensive to move the ore back and forth from Iceland then 15 megawatt hours per ton. I don't know how much energy it goes into moving 1 ton of stuff by sea or how it scales (that is, how much energy it takes to move 1 ton, and how much energy it takes to move 10 tons). It would be interesting to find out.

Brainwashing

2007-03-03T23:07:00.000+01:00

I was watching a documentary earlier this evening, its called Jesus Camp and is about how the evangelic christian movement is indoctrinating the children of its members. This is one amazing movie.

It shows how the kids are at a bible camp and how they are exposed to ultra religious believes without anyone to doubt for them. They seem to have been raised to not doubt what the pastors or preachers are telling them (but doubt what all the others are telling them) and so they believe it fully when they hear sentences like "you are the chosen generation", "I believe that you are the generation that will bring forth the second coming of Jesus" and others in the same category. This does scare me since the kids become susceptible to messages like "you are gods warrior", "go fight the good fight" etc etc, how are they supposed to interpret that message? Is there any difference from these teachings and what the people of Taliban teach their children?

I admit that there was nothing in this movie that told straight out to the children, go and kill the enemy, and the only enemy that was mentioned there were liberals that were pro abortion (this documentary was taken as supreme justice Samuel Alito was nominated and later appointed for the supreme court) but that doesn't really matter. The ground work has been done, these kids are susceptible to all kinds of ideas their teachers like to teach them. They are open to anything, they don't question what they hear from their teachers.

Personally I don't mind grown up people wasting their time in stuff like that, but when it comes to kids, there I say stop. Kids should only get their education from moderates, be they religious or not.

Conservapedia

2007-03-03T01:12:00.000+01:00

People just never stop to amaze me! Seems that some religious fanatics (is that to strong of a wording? :-) ) were not satisfied how the rest of the world viewed the universe and made the text in the online encyclopedia wikipedia so they started their own "encyclopedia" called conservapedia. I especially like the comparison last in that article. I think I will stick to wikipedia even though it should be taken with a grain of salt just like most you read on the internet (or read in general, doesn't just apply to the internet). Hmmm, maybe this story is just bogus since it is published on the internet!

Nope this site really does exist here.

Ooops, sorry

2007-03-03T00:58:00.001+01:00

Now, this is just funny!

Hukkle

2007-02-26T12:46:00.000+01:00

This movie is highly recommended! If you get a chance to see it, grab it! There are not a lot of movies that make me go WOW, but this one did. I saw it here at Cinemateket in Copenhagen 3 years ago and I still remember the feeling of WOW when I left the cinema. I am writing about this now because a friend of mine asked me the other day what kind of movies make me go WOW and I was going to tell him about this movie but I could not remember the title of it so I decided to dig it up from my back catalogues of movie listings from Cinemateket and file it here so I wouldn't forget it again and hope someone else will enjoy this movie when/if they see it.

No phone

2007-02-17T21:05:00.000+01:00

Like Cake sang at one time then I have no phone at the moment :-(
I lost it yesterday and am not expecting to get it back. There is no great loss in the phone itself, just the content in it, a lot of numbers of friends and family. So I guess I have to either be without phone for a while or gather together some money to buy a cheap phone. I think I will try to be without phone for a while, see how it goes :-)

Medicine

2007-02-13T22:39:00.000+01:00

Every morning I take a Paroxetine medicine that prevents me from getting panic attacks and helps me function in my daily life. Today I had to get a refill on my dose and went to the pharmacy. The main distributor for this medicine is Glaxo Smith Klein and their version is called Seroxat (Paxil in the USA, there are actually different names for different countries, see the above link) and last time I checked it cost around 500 dkr which is pretty much. So I usually get a copy medicine that is a lot cheaper but usually costs around 150 to 200 dkr. But today I was pretty amazed, got a copy medicine from Ratiopharm which I think is stationed in Ulm Germany and it only costed 70 dkr! Now that is just amazing I think. How on earth can someone sell medicine for 500 dkr when a similar product (which perhaps has some other side effects, but how many patients suffer from those?) costs 70 dkr? What is the economics of this? I don't understand this.
I would think that when someone sells a cheaper product then you and can offer all the supply then that seller would force you to sell your product cheaper. But this does not seem to be the case in the pharmaceutical industry.

Weird Al Yankovic

2007-02-11T15:26:00.000+01:00

I went to the movies yesterday to see Apocolypto (or what ever it is called), not such a good movie. Interesting first part but boring last part. After the movie we went to this bar called Retro and had two beers there. Pretty typical bar with young people in it (most were younger then me I think :-) ) and accordingly loud boring music, but at one time I heard the sweet melody of Weird Al's new single White and Nerdy! Now it is a parody of another song that I don't know but the lyrics were unmistakable. My humor rose immediately since I am white and nerdy and do like his lyrics. Is it a sign of getting old when you go to a bar with two friends and the best thing there is a song by a comedian?

Stress and sociophobia

2007-02-05T01:39:00.000+01:00

I just saw a good episode on the danish TV. The episodes are called Viden Om (which basically means "knowledge about") and this one was about fear and anxiety. This thing is pretty amazing. They said that almost 200.000 people here in Denmark (population around 6 million) suffered from some sort of anxiety disease (I am one of them).
Now how this got to be like this they got a psychologist to explain that our brain was built over millions of years and during that period we usually lived in strict structural social environment of no more then 60-70 people. Today we live in big cities with million people in them and no social structure that we put ourselves into. So our brain cant handle all these differences between today's life and the life it is "used to". So we are sort of living in a stressful environment that gives rise to overproduction of cortisol that attacks our brain and makes us more stressful, forgetful and less equipped to learn new things. Maybe that's why the ideal place for some of us to live in is a small village with few people, get out of the city and into a more rural area. That's at least what I want to do.
Pretty amazing huuuhhh?? I think so, the brain is a magical thing. Specially if you consider the fact that it is actually trying to figure itself out :-)

Disapointing!

2007-01-31T23:27:00.000+01:00

Yesterday was a big disappointment to me, I was watching the handball game between Iceland and Denmark (I just had to watch it since I am an Icelander living in Denmark) and Iceland lost. Ok, we lost, but the way we lost was simply amazing! It had gotten into overtime and when there were 5 seconds left of the overtime the score was tied! More exciting it cant be but when there were 2 seconds left the bloody Danes scored and won the game. Talk about luck!
Well, better luck next time to Iceland.

Weather

2007-01-31T21:55:00.000+01:00

When I left the lab this evening the wind had picked up a little bit (was up to 15-20 m/s) and when I came home I discovered that it was a bit difficult getting into my room because I had left the window open. When I leave my window open the wind seems to over pressurise my room and it gets difficult to open the door to the corridor. But this day I discovered something "funny".

After I had eaten in the kitchen (which is not in my room, we are 12 that share a kitchen in this dorm) I went back to my room to do some work and discovered a strange smell in my room, couldn't quite place it but I knew this smell. At the moment it is a bit like I have a cold, small headache and a sniffling nostril so I discarded it as something to do with that but the smell was still there, maybe the wind blew something into my room that smelled like that. Then I had to go again to the kitchen so I passed my bathroom and the smell was strongest in there. Ohhh myyy ... what has happened???

I open the toilet and voila! No water in the bowl and there is just sweet shitty smell coming out of my toilet because there is a dry path all the way to the sewer. Easy to fix, just flush the toilet once and the bowl fills up with water and stops the smell from coming up to my room and pleasing my nostrils.

What a strange design that this could actually happen when the wind blows outside and the window is open (this doesn't happen when the wind blows and the window is not open or when the wind is not blowing and the window is either open or closed, I don't think other factors count in this). Maybe I should close the door to my bathroom when I leave in the mornings? I would really like to be able to have my window open when I am not home because it cleans out the air in my room, I don't like stale air.

The classics

2007-01-23T22:28:00.000+01:00

Need to brush up on some of the classics in literature? Well, don't spend your precious time on reading, just listen to them instead while you do something useful in the meantime. If you look through that website you will find a lot of useful audio files, from universities and podcasts of all genre.

Am otherwise to full today to say something of worth, just had dinner with friends and we ate a LOT of beef with potatoes in cream sauce. I think I wont have to eat again until the weekend when the next party is!

Storing an image in a single photon!

2007-01-22T22:57:00.001+01:00

Yes, you read it right, storing an whole image (like of yourself taken with a normal camera) in a single photon. That is impossible you would think! But what hasn't been done today with modern technology in quantum optics? They have teleported information across a small distance here Copenhagen amongst other things. But this headline is actually just what your guts tell you, bullshit.

For the past few days many news media (including specialized science media like physorg.com) have botched up a science breakthrough and made it into something it isn't. I don't know whose to blame (if it is the science writers or the people who made the press release because the news was out before the article got published so most science writers didn't read the article) but when a team of science writers all make the same mistake what is the public to think?

The mistake they made is saying that an experiment that researchers at University of Rochester could carry a whole image in a single photon when all the experiment did was slow light down and make the light continue to withhold information during and after the slowing which had not been done before.

You know that you can get information about the shape of a thing by shining light on it and look at its shadow, right? So you know how a cross section of the thing looks like without looking at the thing itself. Or you can have a mask and shine a light through the pattern in it and the pattern will emerge on the wall behind the mask. Thats just what these researchers did. They shone a lot of light through a mask and recorded the light afterwards, but in between the mask and the detector they let the light go through a certain gas that was specially prepared so it would slow the light down and allso not make the light loose information about the original pattern. What got the science writers confused was that they managed to do this for very low light levels, so low in fact that in each light pulse there were less then one photon (0.8 actually, now how is that possible?), but they still sent a lot of those pulses to recreate the original image, they did not send one photon through the mask and then detected it and recreated the image using only that one photon, no sirrrreeeeee.

Snowing outside

2007-01-22T09:04:00.000+01:00

Its snowing in Copenhagen! We havent had a shred of winter so far and this morning I wake up and lo and behold, outside white flakes tumble down to the ground. Life is full of surprises sometimes.

Which reminds me, I was reading a book by Haruki Murakami called Norwegian Wood (published in 1987), in it one of the characters has a grandparent that has this motto "Life is like a box of chocolates" ... hmm, I know this quote from somewhere. Forest Gump! Little research on wikipedia and voila, the book Forest Gump (published in 1985, movie in 1994) never had that quote, the book said "Being an idiot is no box of chocolates". So the movie borrowed that line from Norwegian Wood, just so you know :-)

BBC API

2007-01-20T11:34:00.000+01:00

A friend of mine just pointed out to me that the BBC have given out a application programming interface to their services, some people have cought up with this and made use with it and others have just come up with ideas of how this could be used. This could be neat, I like a lot of the programs on BBC World and find theyr website not so transparant to navigate maby I can make an interface to theyr programs that are available online using this service in a better way.

Labview

2007-01-19T21:01:00.000+01:00

I have been programming a bit in LabView for the past few weeks and man what a stinker!

Here are a few pointers to new programmers in LabView.

First: The if condition is called case in LabView, you put up a case and give it a boolean input, this makes it so that any output of the case (that is any wires going out of the case) have to have output from both conditions, not like if statements in conventional programming, major headache!

Second: Trying to gather up elements into an array by using while/for loops, major headache for the first time but then you get the gist of how this programming language works and understand the loops then you can make them work ok, not great but ok (that is far from satisfactory).

Third: A graphical interface! What on earth are people thinking! This is the worst interface ever, all the wires get bungled up and it is really hard to keep track of what is what. To make a simple loop you need lots of space on the screen because the icons are so big.

There is more but I am at home now and dont remember what else there was. But the bottom line is this, dont use it for anything else but communicating with peripherals, dont do any data handling with it, its a pain in the ass! I am sure you can do it efficiantly (there must be a reason why all these engineers like this application so much) but getting to that stage is pretty tough if you want to self educate yourself. Go rather with python, much simpler and more powerfull.

Exploding doors!

2007-01-18T22:20:00.000+01:00

At school yesterday we were talking about the main entrence to H. C. Ørsted institute. It has 4 doors on each side of a small hall and each door (8 in all) have big windows in them, there are pumps that keep the doors from slamming when released if open. The thing about these doors is that they open out instead of in like most doors do and a colleague of mine was wondering of why that is. Apparantly they did this design because if an explosion would happen inside the building (the doors are in the chemistry part of the building, we physicists dont do explosions that often) then the doors would fly open and not shatter the glass in the doors. He and another colleague thought this was bullshit but I am not so certain, I think glass can be strong enough to press open the doors (even though there is this dampening pump on them). What do you think?