Changing the Blog's Screen Width

http://bloggersentral.blogspot.com/2009/06/how-to-change-blog-width.html

Learning in Games - Some Notes

Strategic Learning and its limits - Peyton Young

One school points optimistically to particular classes of games that can in fact be learned by simple updating procedures, such as learning minimax equilibria by fictitious play (see Chapter 6). This school also points to the fact that any game can be learned by Bayesian methods provided that the priors are sufficiently aligned to begin with (Kalai and Lehrer, 1993).
The other school views the situation more pessimistically. Its adherents point out that simple learning procedures tend to work only in special cases, such as zero-sum games, potential games, and so forth. Moreover, they are unimpressed by the fact that Bayesian methods lead to learning if the priors are sufficiently aligned to begin with. First, Bayesian reasoning makes extreme demands on the computational capacities of the players, and hence is not a plausible model of decision making by human beings. Secondly, even if one is willing to overlook the empirical implausibility of this approach, the amount of coordination required to learn equilibrium effectively assumes some notion of pre-equilibrium in the prior beliefs. Hence it does not solve the learning problem in a robust sense. (These matters are treated in Chapter 7.)
The purpose of these lectures is to survey results on both sides of the question. On balance, I shall give a little more weight to the positive side, though not in a way that will please all of the positivists. I begin by examining simple forms of learning behavior that depend only on realized payoffs and simple statistical summaries of historical data. These include forms of reinforcement and no regret learning, which turn out to be closely connected. Some of these rules converge in long-run average behavior to correlated forms of equilibrium, including standard correlated equilibrium and variants thereof (see Chapters 2–5). An important property of these learning rules is that they are robust, that is, they require no prior knowledge of the opponents' payoffs or strategies. Significantly, however, they do not yield Nash equilibrium behavior except under special circumstances.
In Chapter 6 we study fictitious play and its variants. These can be viewed as primitive forms of Bayesian learning in which players use simple statistical models based on past evidence and choose best (or almost best) replies given the evidence. Smoothed versions of fictitious play have long-run average behavior that is similar to that of no regret learning, but they do not converge to Nash equilibrium except in special cases.
We then examine the case in which players are very sophisticated in order to see how much can be gained from a high rationality perspective (Chapter 7). The major positive result here is due to Kalai and Lehrer (1993), who show that Bayesian learning leads to Nash equilibrium.
Our concern here is with the learnability of Nash equilibrium in games with finite action spaces. If one allows infinite action spaces, there exist games in which one cannot even determine in finite time whether a Nash equilibrium exists, let alone learn it by a decentralized process (Rabin, 1957; Prasad, 1991, 1997).

install acroread in fedora

wget http://ardownload.adobe.com/pub/adobe/reader/unix/8.x/8.1.2/enu/AdobeReader_enu-8.1.2-1.i486.rpm
yum -y localinstall --nogpgcheck AdobeReader_enu-8.1.2-1.i486.rpm
/bin/rm AdobeReader_enu-8.1.2-1.i486.rpm

Debian commands

To have alternate versions of the same program like matlab, java, etc
man 8 update-alternatives
/usr/sbin/update-alternatives --list matlab


To install a new font (true type) put the font in /usr/share/fonts/truetype/ (in debian) and run
fc-cache -fv
then restart X ( /etc/init.d/gdm restart if using GNOME display manager)


To sort folders in current directory by size
du --max-depth=1 ./ | sort -n -r

Some good technical links

For fixing NTFS not mounting in Linux (Debian) check this link :http://ubuntuforums.org/showthread.php?t=656025&page=2

how to install any package in latex

create a texhash directory in home folder. download the package say "latex-beamer.ter.gz" to a folder inside the texmf/ tree.say "texmf/latex/beamer/". now all the contents of the package should be put in this directory.
Then run "texhash" for latex to find these files.

if you have any dtx file in the package like for eg. "empheq.dtx" then you need to run "tex empheq.dtx" to create the runtime environment files.

wireless cards supported on linux

REFERRED FROM : http://sushant354.blogspot.com/2007/02/wireless-card-supported-for-linux.html

Linux limited support for wireless devices makes one often switch to windows. I often wanted wireless cards that work on linux without any effort. If you want a wireless card to work without any problem, buy a Prism chipset supported on linux exclusively at
http://prism54.org. The card that I have is a Netgear WG511 (Made in Taiwan and not China).

Yesterday I also got a Ralink chipset exclusively supported at http://rt2x00.serialmonkey.com/wiki/index.php?title=Main_Page for just $16.

My card is Gigabyte WMKG and it works flawlessly on linux. You can find other cards with Ralink chipset at http://ralink.rapla.net/

You may also find a huge bunch of Atheros chipset being supported at http://www.madwifi.org.

Backup your data periodically

REFERRED FROM : http://sushant354.blogspot.com/

Losing your computer data is a bad thing. One good habit is to regularly back up your data. But manually doing this is too cumbersome and so we need automated scripts to back up the data. Here is a small script that I use to back up my own desktop daily. It uses rsync protocol over ssh. You need to have ssh, rsync and ssh public-private key pairs for your back up machine. Setting up SSH key authentication is easy and here is one of the link http://www.ece.uci.edu/~chou/ssh-key.html

Add this script to your cron settings. For linux copy this file to /etc/cron.daily/ directory.

The benefit of using rsync is that only changes over the last week will be exported and it will save network bandwidth. SSH provides the encryption layer so that others cannot snoop on your data when you are backing up. This code is under Public Domain License. Customize it to your needs and auto back up your home directory from now onwards.

#!/usr/local/bin/bash

RSYNC=rsync
SSH=ssh
KEY=/home/sushant/.ssh/id_rsa
RUSER=sushant
RHOST=mybackupmachine.com
RPATH=backup/daily/`date +%u`
LPATH=/home/sushant/

$RSYNC -avxz --exclude=".*" --force --delete --delete-excluded --ignore-errors -e "$SSH -i $KEY" $LPATH $RUSER@$RHOST:$RPATH

TECH TIPS

In case of any problem in loading firefox extensions, delete the extensions.ini, extensions.rdf, extensions.cache files in the profile folder. They will be regenerated on firefox restart.
For eg: the profile folder will be /home1/rohithdv/.mozilla/firefox/e77hmcu6.default . where /home1/rohithdv is the home folder.

Some real cool Lifehacker links ..mind you ..these will eat up your time ..! :)

http://www.lifehacker.com/software/gmail/hack-attack-become-a-gmail-master-161399.php

http://www.lifehacker.com/software/feature/hack-attack-mouseless-firefox-139495.php

http://lifehacker.com/software/technophilia/yubnub-web-search-command-line-275460.php

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Linux command reference

Check out this cool link : lists commonly used unix commands - http://www.pixelbeat.org/cmdline.html





Geek to Live: Visualize your hard drive usage - Lifehacker

Command line: du (disk usage)

Not so much into this whole graphical user interface thing? Command-line lovers can also use the du (disk usage) command to get an idea of what's taking up what. The -h parameter makes the file sizes human readable. From Cygwin on Windows, or the Mac Terminal, cd into your directory of interest and try:

$ du * -h

  

The output will look something like:

28M     FileFormatConverters.exe

28K     LH_Logo_Store_Image.jpg

32K     Lazy_Store_Image.jpg

5.3M    photos-for-flickr

52K     Travel form - small Word 03 - gtrapani.doc

28K     Travel form - small.docx

16K     emailnewgoogdocs.png



  

A few more du hints:

• To just see directory sizes, drop the star and just use du -h
• To sort the list of files by size, use du -h | sort -n
  
  du -k | sort -nr (Thanks for the correction, Dr. Drang!)

This article at Linux.com, Disk usage analysis and cleanup tools, also has more on du and other 'nix-based GUI tools.

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Example Note 1

This is an example of a formatted note note

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Some Cool Vim Features

:ta /functionname - to search for function names when we dont know the complete function name
:tn - iterate through all the matches of the previous command.

:s/old/new/g - replaces all occurrences on the current line

:!ls - executes external commands

:r - inserts the filename to the position of the cursor

:r !ls - inserts the output of ls to the cursor position

use h j k l for cursor movement in vi

v - Visual mode to select text.
follow the above by operations like 'y' ( to copy ) or 'd' (to delete)

Some UNIX tips I used

To select multiple emails in pine :-

For Eg : Deleting Multiple Emails

To delete multiple messages in Pine you first need to enable the
aggregate command set. Then use them to mark and delete groups
of messages.


1. From the main menu Press S (Setup)
2. Press C (Config)
3. Scroll down using the down arrow key to:

[ ] enable-aggregate-command-set

4. Press X It should now look like:


'[X] enable-aggregate-command-set'

5. Press E (Exit) to exit the setup. You will be asked to confirm the change.
6. Press Y (Yes)

You should now be back at the main menu.
7. Press I (Index) This will put you in the inbox index.


The commands you need to use are ; (select) and A
(Apply). If you Press O once or twice you should see
these on the menu. But this is not necessary to actually
use the commands. Now we show two examples of deleting multiple Emails.


To delete the first 1000 messages:


1. Press ; (Select).
You will be asked for what category.
2. Press N (Number).
You will be asked to enter a comma delimited list or use a dash
for a range.
3. Type 1-1000.


The system will respond by placing an X in front of the first
thousand messages. Next you will delete the messages.


4. Press A (Apply). You will be asked which command you want to apply to the marked
messages.
5. Press D (Delete)
6. Press X (eXpunge)


Instead of pressing X (eXpunge) you could also quit pine and
answer Y(Yes) when it asked if you want to expunge them.


********************************************************************************

Saving a Message to a Folder You Specify

1. At the Message Index screen, use the arrow keys to highlight the message you want to save.
2. Type S (Save) to save a message.
3. You are asked if you want to save it to the saved-messages folder or another folder:
SAVE to folder [saved-messages]:
4. Type a folder name and press .
For example, to save a message to a folder named "friends," type friends and press . If this is the first time you have named this folder, you see the message:
Folder "friends" doesn't exist. Create?
5. Type Y or press to create the folder.
Once you have created the folder, or whenever you type the name of a folder that already exists, you see a message like this one:
[Message "#" copied to folder "friends" and marked deleted]

****************************************************************************************************


to find pdf files from a root dir with a modification date in 2007.
find ./ -name "*.pdf" | xargs stat -c='%x %n' | awk '{ if ( substr($1, 1, 5) >= "=2007" ) { print $1 $4;}} '

to untar all tar.gz files in a directory
for filename in *.tar.gz
do
tar zxf $filename
done


if u want to open a Xsession from a remote login , first add the IP of the remote computer to the access list of the host computer using the cmd : xhost + . Then set the DISPLAY variable on the remote computer to the IP of host computer using the command - export DISPLAY=:0.0