loopback http://pierrelucbacon.com Sun, 20 Dec 2009 02:19:37 +0000 http://wordpress.org/?v=2.7.1 en hourly 1 Latex your instant messaging http://pierrelucbacon.com/2009/12/16/latex-your-instant-messaging/ http://pierrelucbacon.com/2009/12/16/latex-your-instant-messaging/#comments Wed, 16 Dec 2009 18:12:53 +0000 admin http://pierrelucbacon.com/?p=267 Probably one of the most useful thing that I’ve discovered this month:

http://sourceforge.net/projects/pidgin-latex/

Pidgin-latex lets you write Latex code normally in your chat conversation and renders the result in real time.

For both parties to be able to see the result, they will have to install this plugin or any other one that is handling the mime type latex.

To switch to math mode, it suffices to enclose the content between “$$” symbols.

latex-pidgin

The install process is straightforward. No trick needed. Just follow the one line instruction from the README.

]]> http://pierrelucbacon.com/2009/12/16/latex-your-instant-messaging/feed/ Tilda: The ubiquitous drop-down terminal http://pierrelucbacon.com/2009/10/24/tilda-the-ubiquitous-drop-down-terminal/ http://pierrelucbacon.com/2009/10/24/tilda-the-ubiquitous-drop-down-terminal/#comments Sat, 24 Oct 2009 06:19:12 +0000 admin http://pierrelucbacon.com/?p=265 I was commenting on Guake in http://pierrelucbacon.com/2008/09/19/3-useful-applications/ but found that it was slightly buggy and polluting the tray in the top panel under gnome with its icon.

A few weeks ago, I stumbled upon Tilda which turned out to be at least equally, and so far, much more usable and interesting to use than Guake. My point behind this is that I loved the fact that the GUI is kept just as clean as I like it: a black border-less window.

Currently on my system, Tilda is launched at startup (System->Preferences->Startup Applications) and is invoked with SUPER-A on the keyboard.

It’s good to have an unobtrusive terminal at the tip of our fingers anytime you need it.

Here is a little screencast to give you  a sense of how it can interact on your desktop:

]]> http://pierrelucbacon.com/2009/10/24/tilda-the-ubiquitous-drop-down-terminal/feed/ PGF and Expected Value of the Poisson Distribution http://pierrelucbacon.com/2009/05/24/pgf-and-expected-value-of-the-poisson-distribution/ http://pierrelucbacon.com/2009/05/24/pgf-and-expected-value-of-the-poisson-distribution/#comments Sun, 24 May 2009 20:56:51 +0000 admin http://pierrelucbacon.com/?p=231 Probability Generating Function for the Poisson Distribution

Let p(y) be the probability generating function for Y.

\begin{aligned} p_y(t) = E(t^y) &= {\sum_{y=0}^{\infty}} t^y p(y) \\ &= \sum_{y=0}^{\infty} t^{y} \lambda^{y}e^{-\lambda} \\ &= e^{-\lambda}\sum_{y=0}^{\infty} {{t^{y}\lambda^{y}} \over {y!}} \\ &= e^{-\lambda}\sum_{y=0}^{\infty} {(t\lambda)^{y} \over {y!}} ~~~~\mbox{Power Series}\\&= e^{-\lambda}e^{t\lambda} \\&= e^{t\lambda - \lambda} \\&= e^{\lambda(t-1)}\end{aligned}

Expected Value of the Poisson Distribution

\begin{aligned}E(Y) = \mu_{[1]} &= {\frac{d(P_{y}(t)}{dt}}\left.{\!\!\frac{}{}}\right|_{t=1}\\&= {\frac{d(e^{\lambda(t-1)})}{dt}}\left.{\!\!\frac{}{}}\right|_{t=1}\\&= {e^{\lambda(t-1)} \cdot \lambda}\left.{\!\!\frac{}{}}\right|_{t=1}\\&= \lambda\end{aligned} ]]> http://pierrelucbacon.com/2009/05/24/pgf-and-expected-value-of-the-poisson-distribution/feed/ Merging pdf files together http://pierrelucbacon.com/2009/04/22/merging-pdf-files-together/ http://pierrelucbacon.com/2009/04/22/merging-pdf-files-together/#comments Wed, 22 Apr 2009 17:20:29 +0000 admin http://pierrelucbacon.com/?p=229 From the gs package in Ubuntu:

gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=outputMerged.pdf file1.pdf file2.pdf

jPdf Tweak, the “Swiss Army Knife for PDF files”, is also a great tool and run out of the box with Java but it might be faster just using the above command rather than browsing through jpdftweak’s GUI.

]]> http://pierrelucbacon.com/2009/04/22/merging-pdf-files-together/feed/ Installing a LaTeX package under Ubuntu http://pierrelucbacon.com/2009/04/20/installing-a-latex-package-under-ubuntu/ http://pierrelucbacon.com/2009/04/20/installing-a-latex-package-under-ubuntu/#comments Mon, 20 Apr 2009 21:06:01 +0000 admin http://pierrelucbacon.com/?p=226 In two easy steps:

  1. Download, extract and create a directory under /usr/share/texmf-texlive/tex/latex/ if necessary. Copy the entire directory, or the single .sty file to that location. (You need to be root)
  2. Run “sudo mktexlsr“

From the man pages:

mktexlsr is used to generate the ls-R databases used by the kpathsea library.  Kpathsea: A library for path searching.

]]> http://pierrelucbacon.com/2009/04/20/installing-a-latex-package-under-ubuntu/feed/ RDI en direct sous Linux http://pierrelucbacon.com/2009/01/29/rdi-en-direct-sous-linux/ http://pierrelucbacon.com/2009/01/29/rdi-en-direct-sous-linux/#comments Fri, 30 Jan 2009 02:05:47 +0000 admin http://pierrelucbacon.com/?p=167 Depuis quelques temps, j’arrive à écouter sans problème le flux video de Radio-Canada sous Ubuntu Linux. Il en va pas de même avec tous les vidéos sur le site cependant.

Je ne sais trop comment je suis abouti à la bonne configuration. Dans tout les cas, il faut se procurer les codecs appropriés dans les bons canaux d’abord (restricted), et ensuite installer Mplayer et Mplayer-plugin.

Ensuite, on peut lancer Mplayer directement en ligne de commande, ou en créant un “lanceur” sur l’espace de bureau de Gnome. C’est ce que j’ai fini par faire puisque j’oubliais toujours l’adresse. Alors, la voilà, justement:

mplayer -playlist http://www.radio-canada.ca/util/endirect/rdidirect.asx

Un logo svg de Radio-Canada peut être trouvé ici http://upload.wikimedia.org/wikipedia/fr/thumb/9/92/Logo_Television_de_Radio-Canada.svg/617px-Logo_Television_de_Radio-Canada.svg.png

pour servir d’icone au lanceur.

RDI en direct avec Mplayer

RDI en direct avec Mplayer

]]> http://pierrelucbacon.com/2009/01/29/rdi-en-direct-sous-linux/feed/ Running Kamikaze with WRT54G under Client Mode http://pierrelucbacon.com/2009/01/15/running-kamikaze-with-wrt54g-under-client-mode/ http://pierrelucbacon.com/2009/01/15/running-kamikaze-with-wrt54g-under-client-mode/#comments Thu, 15 Jan 2009 05:47:00 +0000 admin http://pierrelucbacon.com/?p=157 Having the internet cable modem and the router in one place in the apartment, I needed a way to connect all my gadgets in my room/office without having to run a dozen of ethernet cables in the hallway. More specifically, I wanted to have my IP phone close to the bed and not to have to run a wire just for that purpose. The main router is an old TEW-432BRP from Trendnet and I had a also an unused WRT54G running Openwrt. Here is the setup I have at the moment and the configuration follows bellow:

Network Overview

Network Overview

Open Network

/etc/config/wireless

config wifi-device  wl0
        option type     broadcom
        option channel  5
        option disabled '0'

config wifi-iface
        option device   wl0
        option network  lan
        option mode   "sta"
        option ssid openNetwork
        option network "lan"

Wep Encryption
/etc/config/wireless

config wifi-device  wl0
        option type     broadcom
        option channel  5
        option disabled '0'

config wifi-iface
        option device   wl0
        option network  lan
        option mode   "sta"
        option ssid wepNetwork
        option network "lan"
        option encryption wep
        option key1 'mywepkeythatyouwontguess'

My intent was at first to setup a WPA2 bridge, but I finally gave up because neither nas or wpa_supplicant (xsupplicant as well) did the job. nas, the proprietary tool for setting up the broadcom chipset, is also a nightmare to debug with its cryptic error messages (or should I say its absence of any error message ?). The configuration file that is shown above is pretty much self-explanatory. Using Wep 128 is a pretty good compromise on security that I would have better avoided, but I think it worth it considering that MAC filtering can be done and that I always have access to a VPN server.

An important thing that you should also not forget finally is to disable the DHCP server on the OpenWrt router because it might conflict with the other router since we are working in a bridged environment.

]]> http://pierrelucbacon.com/2009/01/15/running-kamikaze-with-wrt54g-under-client-mode/feed/ Installing Spim/Xspim http://pierrelucbacon.com/2009/01/05/installing-spimxspim/ http://pierrelucbacon.com/2009/01/05/installing-spimxspim/#comments Tue, 06 Jan 2009 03:17:08 +0000 admin http://pierrelucbacon.com/?p=154 Spim is A MIPS32 Simulator freely available for Linux, Mac and Windows. The process for installing the software from source is not as nice as we would expect it to be.
Download source code from:
http://www.cs.wisc.edu/~larus/SPIM/spim.tar.gz

You will probably need to get Bison and Flex:

sudo apt-get install bison flex

Don’t forget:

sudo apt-get install libxaw7-dev

Otherwise you’ll get “X11/Xaw/Cardinals.h: No such file or directory”

Build and install xspim first:

cd xspim; make && sudo make install

Then spim:

cd ../spim; make && sudo make install

If you install spim before xspim, the latter will fail with “install: accessing `/usr/lib/spim/exceptions.s’: Not a directory”

]]> http://pierrelucbacon.com/2009/01/05/installing-spimxspim/feed/ Check start up date under Linux http://pierrelucbacon.com/2008/12/19/uptime/ http://pierrelucbacon.com/2008/12/19/uptime/#comments Fri, 19 Dec 2008 06:49:45 +0000 admin http://pierrelucbacon.com/?p=146 Obviously “uptime” provides that information but only gives the number of days. On one of my server, it shows:

01:39:53 up 445 days, 11:15,  2 users,  load average: 0.00, 0.00, 0.00

But when did that happen ? I don’t know any option which can compute the actual date using uptime.

I realized the other day that I can use “ps” to display the same information just by checking start up time for the “init” process.

ps -o lstart -C init | tail -n 1

do the trick and displays:

Sun Sep 30 15:24:22 2007

Whoa ! That’s a long time ago …

Use “alias” if you don’t want remember that:

alias uptime2='ps -o lstart -C init | tail -n 1'
]]> http://pierrelucbacon.com/2008/12/19/uptime/feed/ Fun with isograms http://pierrelucbacon.com/2008/12/06/fun-with-isograms/ http://pierrelucbacon.com/2008/12/06/fun-with-isograms/#comments Sat, 06 Dec 2008 04:39:31 +0000 admin http://pierrelucbacon.com/?p=137 An isogram is a meaningful string, generally  a word or a phrase, made of distinct letters. When playing with combinatorics, it’s fun to learn about the existence of such words. Let’s take the word COMBINATORICS, then there are 13!/(2!2!2!) ways to form a new 13 letters words from its letters. In fact, we must divide 13! by those letters which are repeated so that we don’t overcount. In this example, “o”, “c” and “i” appear 2 times each.

One of the longest english isogram is UNCOPYRIGHTABLES. With 16 letters, and no repeated letters, the number of possible arrangements amounts to 16!. Pretty big to picture up…

http://en.wikipedia.org/wiki/Isogram

]]> http://pierrelucbacon.com/2008/12/06/fun-with-isograms/feed/