Dodgy ram

After effects of running a computer with some seriously broken RAM sticks:

R and Datetimes and stuff

You may have figured out at this point that these posts' primary purpose is so I don't have to figure out this stuff again if I stop using R for 6 months.

Anyway, if you've got some strings and you want dates, use
as.Date(x)


But if you want datetimes (i.e. don't want to lose the time component), use
as.POSIXct(x)


Also, subset is nice:
subset(dat1, (t > '2009-01-01') & (t < '2009-01-05'))


Create a frame:
#make up some data
x = seq(-2*pi, 2*pi, by = 0.05)
#create the frame
datx = data.frame(x=x)
#add another column
datx$sinx = sin(datx$x)
#show the columns
names(datx)
#gives: [1] "x" "sinx"

See also http://www.statmethods.net/input/datatypes.html for a nice brief intro to R's different structures.

ggplot2 is awesome

I like R, but R+ggplot2 is awesome.



library("ggplot2")
x = seq(-2*pi, 2*pi, by = 0.05)
x1 = x + rnorm(length(x))/10
qplot(x, sin(x1), color=rgb(abs(sin(x)),0,1), geom = c("point", "smooth"))

Requires that you
install.packages() ggplot2, of course.

I'm currently working through Getting started with qplot (pdf).

The R Project for Statistical Computing

I've been playing with The R Project for Statistical Computing. I quite like it.

Here's a few of the first things I did, just playing around:

x = seq(-pi, pi, by = 0.01)
plot(sin(x), col = rgb(abs(sin(x*3)), 0, 0), cex=.2+3*abs(sin(x)), pch=16)
points(cos(x), pch=16, cex=.5, col = rainbow(length(x)))

n = 10000
breaks = 100
plot_count = 5
cols = rainbow(plot_count)

plot(x = c(), xlim=c(-0,1), ylim=c(0,3), main = "distribution of random sums", xlab = "Sum of N random numbers between 0 and 1/N", ylab = "density")

runifrep = function(n, reps) {
 tot = 0;
 for (i in 1:reps) {
  tot = tot + runif(n)
 }
 tot/reps;
}
for (i in 1:plot_count) {
 a = hist(runifrep(n, i), breaks=breaks, plot=0)
 lines(y = a$density, x = a$mids, col = cols[i], pch=3, cex = .1, xlim=c(-4,4), lwd = 3)
}

Note that cex is symbol size, pch is symbol and lwd is line width. http://www.harding.edu/fmccown/R/#misc has a nice list of symbols.

.com.au registration prices

I just spent half an hour looking at every auDA Accredited Registrar's website, looking at how much it costs to register a .com.au domain.

Sometimes they actually listed prices, but often the easiest way was to just search for a random domain and wait for them to tell me what it would cost. It's just a quick survey, and it's quite possible that I got some of them wrong. All the prices should be for 2 years, but I didn't read the fine print too carefully. I expect some of the URLs won't work without the POST data, but they're really only there as hints for the auDA list.


http://www.aussiehq.com.au/business/domains/
$59

https://manage.planetdomain.com/order/execute/multiDomainSearch?domainName=asdgasdfasdf&tlds=.com&tlds=.net&tlds=.org&tlds=.mobi&tlds=.asia&tlds=.biz&tlds=.info&tlds=.com.au&tlds=.net.au&tlds=.co.uk&tlds=.org.uk&tlds=.us.com&tlds=.us&tlds=.ca
$33

http://www.clickngo.com.au/domains-pricing.html
$59

http://www.webaccess.com.au/domain_names/home.html
$49.50

http://www.ddns.com.au/prices.php
$65

http://intaserve.com/
$27.95

http://www.domaincandy.com.au/pricing.asp
$99

http://www.domainregistration.com.au/
$127

http://theconsole.netregistry.com.au/order/execute/domainSearch
$26.97

http://www.mdwebhosting.com.au/myaccount/domainchecker.php
$18

https://secure.westnethosting.com.au/signup/stage2.aspx
$88

http://www.austdomains.com.au/pricing.html
$69

http://www.domaincentral.com.au/
$37.95

http://www.namescout.com/dot_au.asp
$27.45

http://www.melbourneit.com.au/cc/order/vieworder?&action=addtobasket&d-asdasdfasdf.net.au=asdasdfasdf.net.au&recheck=true&d-asdasdfasdf.com.au=asdasdfasdf.com.au&added_catalog=1895165,1895166,1895167,1895168
$140

http://www.domainbandit.com.au/site/domain_search.cfm
$66

http://www.tppinternet.com.au/domains/search-results.php
$99

http://www.safenames.net/DomainNames/DomainRegistration.aspx
?

https://ssl.smartyhost.com.au/signup
$40

http://www.cheaperdomains.com.au/hspc/index.php
$35

http://www.bottledomains.com.au/
$99

https://www.enetica.com.au/register.cgi?action=lookup&ludomain=asdfasdf&x=79&y=11&domaintype=.com.au&domaintype=.com&domaintype=.net.au
$69

http://www.domain8.com.au/
auction

https://www.instra.com/en/domain-application/login/step-01
login before price

https://www.anchor.com.au/domain-name-registration/domain_order.py
$69

http://www.explorer.net.au/show.php?f=pricing
$99

http://www.godomains.com.au/welcome/
$98

http://www.connectwest.net.au/termsconditions/tc.cgi?domainName=asdgasdgasdfg&tld=com.au
TOC before price

Windows Mobile Emulators

I was looking for a touchscreen mobile emulator to test using Lazarus to compile for my mobile. Microsoft's Windows Mobile 6.1.4 Professional Images (USA).msi seems to fit the bill. Note that for some reason "Professional" means "Touchscreen" and "Standard" means "Keypad".

This post, Installing and running Windows Mobile emulators, was useful for setting up networking.

And, of course, the Windows CE Interface page on the Lazarus wiki was useful.

Pavement Marking Trial

I saw this odd road marking on the way to work. Guess what it means (explanation after the break):