Monday, September 14, 2009

R - percentiles

I just needed to find some percentile thresholds and thought that it'd be easy with R. Well, it is!

So, load the data

data = seq(0,1,0.01);

Then you can get quantiles like so:


0% 25% 50% 75% 100%
0.00 0.25 0.50 0.75 1.00

and percentiles by using the vector argument to quantile (in this case I'm looking at the 0th to 1st percentile):

0% 0.1% 0.2% 0.3% 0.4% 0.5% 0.6% 0.7% 0.8% 0.9% 1%
0.000 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009 0.010

Friday, September 11, 2009


Ever lost a terminal which had an active job running? Ever wanted to check in on what you'd been doing from home *and* wanted or needed the session history as well?

'screen' is your friend. If you're starting work that's important or that you may want to check from another machine it's a real time-saver. Have a look at the man page for more details than you can shake a stick at.

I've only been using it for a little while, so the only caveat I've found so far is that I have to remember to give the sessions a reasonable name before I start them. Otherwise, if you've got a lot of sessions, it's a time waster trying to find the right one. The '-t' flag sets the title for the default shell; more importantly the '-S' flag sets the session title. I've been using the same string for both (will probably set up an alias to deal with the duplication soon).


shell1> screen -t data_loading -S data_loading
shell2> screen -ls
There are screens on:
21802.data_loading (Attached)
20237.pts-10.hamilton (Attached)
1376.variance_analysis (Attached)
6639.pts-8.hamilton (Attached)
9881.cluster_jobs (Attached)
5 Sockets in /var/run/screen/S-paul.

You can see from the above listing that there are 5 sessions (all currently attached). There are two listings there with no session title and I have no idea what I'm doing in them... but for the other three it's obvious (at least to me).