Simulating Ising model with CFTP

I should've made this post long time ago.


I have a working code on how to simulate an exact sample of an Ising model using Coupling from the Past method. This is of course going to be the front section of my dissertation on which I'm starting to type out(soon I hope).


Anyway I've written the code on Mathematica and it can be downloaded from


http://www.uploading.com/files/48AGO45J/ising_CFTP_noisy_besag_.nb.html






Just load the file in Mathematica and evaluate notebook.

A description of the diagram above:

• The red sequence starts from the maximum state, i.e. all +1 states.
• The blue sequence starts from the minimum state, i.e. all -1 states.
• We obtain exact sample if at time 0, the final red matches the final blue.
• The yellow/green sequence shows states which are different(yellow) and states which are the same(green) between the red and blue diagrams on each side.

Currently I am(almost successfully) completing a program which samples a 3-state Potts model. However, improvements I would like to make to the above Ising model is a method of testing whether my model is in fact a good sample.

Comments and feedbacks are appreciated. I accept any questions.

Note: A method I use to speed up the model above is the Besag coding trick. You can read more about it from my presentation here.

Canon Rock

New version of canon rock, this one I like. Just the type of music that's nice on electric guitar. I wish I have an electric guitar....... anybody wanna buy me 1?

If you dunno what's canon rock, where on earth have you been? Not being on youtube for a very long time eh?

Below is the famous canon rock by funtwo:

Tune Hotels

Forty Tune Hotels target in S-E Asia

Fuyoh, talking about the no-frills business, when somebody leads the way and shows us how to turn it into a profitable business, seems like everyone else is taking the cue and going into this niche market.

Undoubtably, when customers look at the attractive price(from RM9.99) what can they expect to get in return. I don't know about you, but to me there are 2 types of travellers, namely tourists and business travellers.

It remains to see who are they targeting. Catch here is business travellers always bill their employers, so they don't have to worry about the cost. Tourists normally buy packages so their choice of hotel is determined by travel agencies.

To be honest, I think only 2 types of people would be their regular customers:

• Couples(Of coz the ones who usually rent by-the-hour)
• Small business owners

What do you think?

＊UPDATE: I should have done my background research 1st, that Datuk Tony Fernandes holds 40% of Tune Ventures which owns more than 70% of Tune Hotels. And a certain somebody is involved as well, the one suing Uncle Jeff and Rocky. Anyway refer to Howsy's post about it here.

Presentation

http://www.uploading.com/files/F5BJPCHR/Presentation1.ppt.html

short 5 minute presentation about the subject

New year, new headache

It's my new academic year now and since it's my 4th year, it's pretty interesting. For once, I've begin to like what I study, and I do mean seriously like(as in love). Statistics to many may be a boring and dull subject, but hey, everyone of you out there knows that we statisticians are important!!!!

I've just got the title for my dissertation about two weeks ago and I have to admit feeling the pressure just only two weeks later. The deadline is sometime in April but there's no time to lose.

I'm thinking what can I do to help me track my progress. Well, fortunately there's this blog, so....... there's gonna be lots of academic things here. If you know what I'm writing or spot an error, please tell me...... PLEASE!!!!

My dissertation title:

Potts models, image analysis, and CFTP

CFTP stands for "Coupling from the past".

Any interested readers can use the below links for some general background on the subject.

Again, inputs are very welcomed and do drop me an email at bosslepton@yahoomail.com. Please if I do make an error, CORRECT ME.

General background:
Propp, J.G. and D.B. Wilson (1996). Exact sampling with coupled Markov chains and applications to statistical mechanics. Random Structures and Algorithms 9, 223-252.
http://research.microsoft.com/~dbwilson/eus/

http://www.warwick.ac.uk/go/wsk/talks/singapore-2004.pdf

http://www.warwick.ac.uk/go/wsk/talks/gtp.pdf