Start your engines; it’s a Linux era!
Well, I’m writing this from my new system. After years on hiatus I migrated to Linux, once again. Setting up a full system on Linux for a Greek user had been one of the greatest challenges.
First,of all setting up writing, reading & printing in Greek was the biggest obstacle, I still recall memories of 2000/2001 when installing the 9th (?) edition of Mandrake Linux, supposed to have full Greek language integration. As if? Second, comes networking with Linux. Win-modems ruled Greek market and made it really painful to read all these articles to even start hoping that you might be near configuring your Internet connection.
Yet, I used Linux till 2003 or 2004 with no Internet connection and used my Windows to surf the net… Courageous, right? Last night I was surfing for open source ideas and stumbled upon Wuby. Wubi is a windows-ish application for Ubuntu, the hottest for users of my clan! I installed on my disk, chose my graphical environment (Gnome, no regrets) and one thing left to check…the Internet highway.
Turns out that, routers (those using Ethernet ports!) are plug & go. Neat! Unfortunatelly, I’m stuck with my USB model my provider gave a couple of years ago ;( Sad thoughts paid a short visit I must admit. But, even this was no real problem, UbuDSL has everything under control :thumps up:
Of, course I installed RKWard, there’s a Windows version, too. I never got to make it work, though…
Damn those businesses!
So many times you’ve in a situation where Excel is your god-sent tool. Yeap, I’m talking about statistics & excel, the 8th sin! I found myself tutoring a couple of days ago and I found myself stuck with Excel. How to perform a stepwise procedure overcoming the burden of VB (which I know nothing about it) or defining cell functions?
There is an add-in that comes handy I must admit, Stepwise Regression Add-In. There is one or two problems when installing and I had a problem with variables names (I solved it using the usual notation x1,x2,…,xn,y I suggest you do the same) but it’s overall good. When in a situation as mine , use it!
A merry wolfram xmas!
Christmas coming & time for fun! Wolfram’s demonstrations give you a sense of the holiday season along some nice demonstrations. I particulary like the “Ornamental Holiday Decoration“
Manipulate[
Module[{level0, level1, level2},
level0 = C[spikey, 0];
level1 =
Flatten[daughterPolyhedra[C[spikey, 0], {d1, ω1, s1}, ρ s1]];
level2 =
Flatten[daughterPolyhedra[#, {d2, ω2, s2}, ρ s1 s2] & /@
Cases[level1, _C]];
Graphics3D[{EdgeForm[],
{Red, egc[level0]}, gg1 = {col1, egc[level1]},
gg2 = {col2, ControlActive[{}, egc[level2]]},
Directive[GrayLevel[0.2], Specularity[colc, 12]],
ecc[{level1, level2}]}, Boxed -> False,
ImageSize -> {400, 400}]],
"layer 1:",
{{d1, 1.5, "distance"}, -3, 3, ImageSize -> Tiny},
{{ω1, 0, "rotation"}, -Pi, Pi, ImageSize -> Tiny},
{{s1, 1/2, "size"}, 0, 1, ImageSize -> Tiny},
{{col1, Yellow, "color"}, Blue, ControlType -> None},
Delimiter,
"layer 2:",
{{d2, 1, "distance"}, -3, 3, ImageSize -> Tiny},
{{ω2, 0, "rotation"}, -Pi, Pi, ImageSize -> Tiny},
{{s2, 1/2, "size"}, 0, 1, ImageSize -> Tiny},
{{col2, Green, "color"}, Green, ControlType -> None},
Delimiter,
"connectors:",
{{ρ, 0.3, "radius"}, 0, 1, ImageSize -> Tiny},
{{colc, Brown, "color"}, Yellow, ControlType -> None},
AutorunSequencing -> {1, 3, 5, 7},
Initialization :> {
spikey =
MapAt[Developer`ToPackedArray,
MapAt[Developer`ToPackedArray, N[PolyhedronData["Spikey"]][[1]],
1], {2, 1}];
mirrorRotateAndShift[gc_GraphicsComplex,
n_, {distance_, angle_, size_}, ρ_] :=
With[{aux =
mirrorRotateAndShiftCF[gc[[1]], gc[[1, n]], distance, angle,
size]}, {C[GraphicsComplex[aux, gc[[2]]], n],
Cylinder[{gc[[1, n]], aux[[n]]}, ρ]}];
mirrorRotateAndShiftCF =
Compile[{{vertices, _Real, 2}, {rPoint, _Real, 1}, distance,
angle, size}, Continue reading this entry »
Web analytics revisited : The Mathematica way!
I found out something really interesting. Men do it with keyboards (not clicks!) and so does Patrick Collison using Mathematica to analyse web data he got from Google Analytics.
See : Hacking for fun and profit with Mathematica and the Google Analytics API [link]
R> if (done=TRUE) tweet me!
Let’s say that you’re fitting a cumbersome model so time is not to waste over a PC staring at the screen half anxious-half bored…
Then, you can always leave and go on with meetings and all your daily routine and have R notify you the results! How?
We will illustrate the situation above using some Bayesian Model Averaging code adapted by Martin Feldkircher & Stefan Zeugner. You should download the code and source everything in R except for the example in the end (after the definition of the functions!).
#The code to get a model
fls.data=read.table(url("http://feldkircher.gzpace.net/links/fls_data_adj.txt"))
data.M=as.matrix(fls.data)
K=ncol(dataM)-1 # nr. of regressors
# this setting corresponds to a uniform prior on the model space (prior.msize=K/2 and theta="fix")
# and the ric specification since K^2> N (with N the nr. of observations) as suggested by fls
model.ric=fls(X.data=data.M,burn=60000,iter=700000,g=(1/K^2),nmodel=100,theta="fix",prior.msize=K/2,logfile=T,mcmc="bd",start.value=rep(0,K),beta.save=T)
This is gonna take s o m e time (really!), so you could let R working and go out for a cup of coffee (typical of Greek people!). Add the following at the end of the above code.
library(twitteR)
sess <- initSession('myUser', 'myPass') # Set your user account info
ns <- updateStatus('A model waits for you @ home 
', sess)
Would you really care enough to check whether the fit is done when outside?
Web analytics : The GPL way!
Increasingly, bloggers want to know more about their readership status turning to more sophisticated tools than the simple ones that their hosting service provide them with. The mainstream option is (tuh-duh!) Google Analytics, yet another competing and open source choice is available, Piwik.
Piwik is really good and you get a hold of your data (know what I mean?). It works as usual, you copy-paste a script JavaScript on your page of interest and it’s all set and done! Unfortunately (for me and the rest wordpress.com users) you have to install the software on your server,so… no web analytics for me!
See also
- Piwik Online demo [link]
- SourceForge.net project of the month (of course is Piwik!) [link]
Trouble (when not) sleeping?
Well, that’s not that encouraging since I tend to sleep on the early hours…
- Short sleep duration ( <5 or 5-6 hours ) increased risk for high BP by 350% to 500% compared to those who slept longer than 6 hours per night. As you know, high BP kills.
- Young people ( 25-49 years of age ) are twice as likely to get high BP if they sleep less. Individuals who slept less than 5 hours a night had a 3-fold increased risk of heart attacks. Complete and partial lack of sleep increased the blood concentrations of High sensitivity C-Reactive Protein (hs-cRP), the strongest predictor of heart attacks. Even after getting adequate sleep later, the levels stayed high!!
- Sleeping for <=5 hours per night leads to 39% increase in heart disease.
- Just one night of sleep loss increases very toxic substances in body such as Interleukin-6 (IL-6), Tumour Necrosis Factor-Alpha (TNF-alpha) and C-reactive protein (cRP). They increase risks of many medical conditions, including cancer, arthritis and heart disease.
- Sleeping for <=6 hours per night leads to 8% increase in heart disease.
Houston we are about to get a problem!:)
source : What killed SAP CEO Ranjan Das and lessons for corporate India
Let it snow!
It’s almost Christmas…
To make it snow on your blog:
- Go to your dashboard.
- Navigate to Appearance -> Extras.
- Check the box next to “Show falling snow on this blog”
source : A Little Snow for the Holidays [link]
Create factor variables in R
Instead of the factor() function which usually applies after defining a vector there’s the gl() base function to do this in one step, eg
freq <- c(204,6,1,211,13,5,357,44,38,92,34,49) row <- gl(4,3,length=12) col <- gl(3,1,length=12) > col [1] 1 2 3 1 2 3 1 2 3 1 2 3 Levels: 1 2 3 tt <- data.frame(freq,row,col) > xtabs(tt) col row 1 2 3 1 204 6 1 2 211 13 5 3 357 44 38 4 92 34 49
R twitts…
You may already know this…
I think I might get an account when get to connect to the Internet in my mobile phone
