Proof: obvious

The paper I wrote about last time got accepted. So that's great. Unfortunately, the paper I had been working on for the past couple of weeks had to be postponed because the algorithm changed the day before the deadline. Luckily, it's now a stronger result, though the proof isn't as cool as it was. Win some, lose some I guess.

Since ipe was released containing one of my ipelets, I got a bug report. Otfried told me how to fix it, so I have updated my ipelets with the bug fixed. (The bug was that if you applied the ipelet and then moved the object and then applied the ipelet again, the ipelet would work on the original version of the object.) So if you follow these sorts of things, both of the ipelets have new versions.

The other thing that has been going on lately is that I have submitted a new paper. My co-authors, Mark and Boris , really did a great job in getting the paper into decent shape. It still amazes me how much a paper can change from when I think I'm done with it to the final product. So anyway, we submitted it to SoCG . It's the only paper I'm submitting there, so I really hope that it gets in.

Otfried has released the new version of ipe . As I had hoped, it uses QT4, and it includes one of my ipelets. Go check it out.

I don't know how hard the port would be, but I think it would be nice to get ipe into qt4 as soon as possible, mainly so that people on Windows can start using ipelets not compiled by Otfried. They could in the past, of course, but the license fees for the qt development libraries on Windows before 4 are in the thousands of Euros range per developer. Starting with 4, the development libraries seem to be free.

I fixed a fairly subtle bug in the ipelet that appeared when the input polygon spiraled heavily. As usual, get it on the ipelets page.

Now with memory management.

Just added a new ipelet to my ipelets page. This one computes the points visible to a point inside a given polygon assuming that the edges of the polygon are walls that can't be seen through. The code for this ipelet is still a bit rough, so don't use it without saving your file first.

I submitted the paper I was working on with Mark to SODA yesterday. It's a good feeling to be done, and we weren't even all that frantic at the last minute. The paper has some good results in it, so it might even get accepted, though I hear that acceptance at a big conference like SODA can be something of a crapshoot.

For almost the entire year until now, I had been writing a paper about an algorithm that Mark and I came up with. The algorithm was pretty complicated, so a few weeks ago I decided to step back and see if I could make it simpler. The result was good -- we shaved off a log n factor from the time and space complexity. However, the paper that I had been working on for months is now obsolete, never to be published. I could salvage a large part of it for the new paper that I am now working on, but it was still a bit discouraging.