EDS Killing Thunderbird

I’ve finally worked out why Thunderbird email has been almost unusable since upgrading my various Ubuntu machines to Precise Pangolin 12.04.

The symptoms were very sluggish Thunderbird interface response, leading to a segmentation fault crash. The crashes only happened sometimes and didn’t seem to follow a pattern of time from start-up.

The EDS Contact Integration Add-on seems to have been responsible. EDS is the Evolution Data Server and although I don’t use Evolution directly, I have registered my various Google and Twitter accounts, which apparently get pulled in by EDS too.

I have quite a few Google contacts (>700), so I can only assume that the add-on is trying to process them all.

Anyway, the immediate problem is solved by disabling the add-on. I use a google contact sync plug-in anyway, which works fine, so as far as I know I’m not missing out on anything.

Statistical Graphing with R

I have been collecting some metrics from the 8 agile teams that I work with and planned to create some nice visual reports to help identify software development practices that could be improved.

The data was initially in an Excel spreadsheet, so I used its built-in graphing capabilities which had been good enough for previous projects. I quickly found problems that made me want to look for a better solution;

• Difficult to create multiple graphs with aligned x-axes.
• Every time I wanted to use the same graph with different data, I’d have to either replace the data or tweak every graph.

So I tried Gnumeric, which has some nice graphing features, but its lack of pivot tables puts it out of the running. Libre Office Calc was much the same as Excel. I tried some Linux graphical plotting applications, the nicest of which was QTIPlot, which solved the common X-axis problem, but its vector output was poor.

Eventually I looked at statistical computing environments and settled on the R Project, a programming language for statistical analysis and graphing. It solved all the problems I was having with GUI based tools and in the process introduced me to a new way of explore my data.

R has a shell, so you can load some data into a variable and then start playing with it. You can easily filter data, apply matrix transformations and feed data through mapping functions.
Once you have the data in the shape you’re interested in, you can run it through one of the built-in functions, which give you lots of standard graph types, or delve into The Comprehensive R Archive Network (CRAN) which is a massive library of user contributed functions for graphing and analysis.

Once you have settled on the transformations and graphs you want to write out, you can write a script that outputs to various file formats, including PDF, SVG and Postscript. At the end of each iteration, I run my script that takes the latest data as a CSV file and outputs all the graphs I need for my report. When I think of new graphs I’d like to include, I add them to my script. It’s easy, reproducible, massively flexible and oh yes… it’s open source too.

Here’s a quick distribution graph (took maybe five minutes)…

This distribution of story estimates (in man-days) shows that;

• Even numbers are more popular than odd numbers
• 9, 11, 17 and 19 are never chosen, presumably due to rounding up or down to 10 and 20.
• There is a general preference for nice small stories.

All this was created with the following R script;

data <- read.table("data.csv", header=TRUE, sep=",")

small_quotes <- data$Original.Estimate[
  data$Original.Estimate <= 576000 & 
  data$Original.Estimate > 0] / 28800

hist(
  small_quotes, col=rainbow(40,0.5),
  main=paste("Histogram of ", length(small_quotes),
    "Quote Sizes <= 20 units"),
  breaks=20, xlab="Estimate", ylab="Frequency"
)

Have fun setting your data free!

Learning Erlang Recursion

I’m learning the Erlang Programming Language and am currently working on the recursion exercise in the erlang course.

The min and max functions seemed pretty straightforward;

min([X,Y]) when X > Y -> Y;
min([X,_]) -> X;
min([H|T]) -> min(H,min(T)).

max([X,Y]) when X > Y -> X;
max([_,Y]) -> Y;
max([H|T]) -> max(H,max(T)).

min_max(List) -> {min(List),max(List)}.

But this is the best I could come up with for the Swedish Date problem; convert an Erlang date in the format {2001,02,03} to “010203″ recursively.

swedish_date() -> swedish_date(date()). 

swedish_date(Date) -> swedish_date(tuple_to_list(Date), "").

swedish_date([H|T], DateString) ->
        List = "0" ++ integer_to_list(H),
        String = lists:sublist(List, length(List)-1, 2),
        swedish_date(T, DateString ++ String);
swedish_date([], DateString) -> DateString.

Can anyone improve on that? I feel sure that recursion could help with the number of digits in each part of the tuple. 2001 → 01, 2 -> 02, etc.

Another Painting

This time, from the north east corner of Ploscha Rynok, looking down towards the Dominican Church.

I had a brief chat with another artist, who's been painting around the square for many years. The chat was brief in no small part because of the limits of not speaking the same language. He showed me a press clipping of him painting in the square.

It's fun painting in such a busy place. Makes you feel like part of the action. Lots of people came up and had a look at the painting and several stopped to talk.

Batyar Day (Rascal Day)

Today is the day they celebrate “Batyarstvo” (an idle and debauched style of life) in L’viv.

A selection of smartly dressed rascals getting up to mischief and occasionally being reprimanded by the police.

Ploscha Rynok is heaving with people today, there’s live music, dancing and some deeply debaucherous foodstuffs.

Beautiful L'viv

I’ve been living and working in L’viv (a spectacular Medieval city near the west border of Ukraine) for a couple of weeks now.

I’m trying to learn a bit of the language, but it’s fairly hard getting your message across. Very few people who went to school during the Soviet era learnt English, because the chances of travelling anywhere where it was spoken were very slim.

Only people who have been in education in the last 20 years are likely to have picked up any English, so at the moment, the cut-off age is early-thirties.

Last weekend, I managed to find an art supplies shop thanks to some helpful ladies in a local art gallery. So I set to work sketching and painting one of the views from my balcony onto Ploscha Rynok (Market Square).

Hopefully the weather will be as good this weekend, so I can get out and paint somewhere else.

Fedora 12 RPM Fusion Smart Channels

I still prefer the usability of Smart Package Manager over Fedora's default package management programs, so here are my Fedora 12 RPM Fusion channels for Smart Package Manager.

rpmfusion-smart-channels-fedora-12.tar.gz