Note to self: Backup bottlenecks # I learnt the following relations the hard way 10 years ago when trying to backup a rather tiny amount of data, went through the computation again three years ago. Still I had to re-do the computation this morning when trying to pull a final full backup from my old MacBook. Posting here for future reference: Note 1: Some numbers like 10BASE-T included only for historic reference. ...
Note to self: Basic R operations # After searching for that all too often and for too long (in particular the “add a column as index” bit): To read a file: d <- read.table(’/home/isabel/input’, sep=’,’, header=T, quote=’’) Useful for getting an overview of the data:summary(d); head(d); tail(d) For sorting some data frame: s <- d[order(d[,2]),]; For adding a column to a data frame: s$idx <- seq(0, nrow(s) - 1, 1) ...
Note to self - link to 3D maps # After searching for the link the third time today - just in case I happen to be again looking for Nokia’s 3d maps: http://maps3d.svc.nokia.com/webgl/index.html is the non-plugin link that works in Firefox.
Note to self: Clojure with Vim and Maven # Steps to get a somewhat working Clojure environment with vim: Install the current vimclojure plugin. Get and install a nailgun client. Add vimclojure to your clojure project pom.xml. Start the nailgun server from within your maven project with mvn clojure:nailgun with the maven clojure plugin. Finally start vim, open your favourite clojure file - you can open a REPL with \sr, when in a function definition you can evaluate that with \et - see also tamining vim clojure ...
Second steps with git # Leaving this here in case I’ll search for it later again - and I’m pretty sure I will. The following is a simplification of the git workflow detailed earlier - in particular the first two steps and a little background. When dealing with remotes the git remote documentation is very useful. When sharing your changes with others the git tutorial on sharing changes is very helpful. ...
Note to self - Java heap analysis # As I keep searching for those URLs over and over again linking them here. When running into JVM heap issues (an out of memory exception is a pretty sure sign, so can be the program getting slower and slower over time) there’s a few things you can do for analysis: Start with telling the effected JVM process to output some statistics on heap layout as well as thread state by sending it a SIGQUIT (if you want to use the number instead - it’s 3 - avoid typing 9 instead ;) ). ...
Note to self: svn:ignore usage # Putting the information here to make retrieving it a bit easier next time. When working with svn and some random IDE I’d really love to avoid checking in any files that are IDE specific (project configuration, classpath, etc.). The command to do that: svn propedit svn:ignore $directory_to_edit After issuing this command you’ll be prompted to enter file patterns for files to ignore or the directory names. ...
First steps with git # A few weeks ago I started to use git not only for tracking changes in my own private repository but also for Mahout development and for reviewing patches. My setup probably is a bit unusual, so I thought, I’d first describe that before diving deeper into the specifc steps. Workflow to implement With my development I wanted to follow Mahout trunk very closely, integrating and merging any changes as soon as I continue to work on the code. ...
Building a Hadoop Job Jar with Maven # Put here as a reminder, so I do not forget about it. There is a really nice tutorial online on Building Hadoop Job with Maven.