2016
05.01
05.01
Exciting news on the Erdos-Szekeres convex polygon problem. arxiv.org/abs/1604.08657
Vanity of Vanities, all is Vanity
Sariel's blog
2016
04.26
04.26
Sanders to declare victory and withdraw from the Democratic party.
2016
04.20
04.20
Not creepy at all… twitter.com/ABC/status/722…
2016
04.18
04.18
“Your lie in April” en.wikipedia.org/wiki/Your_Lie_…
2016
04.18
04.18
Michigan governor to fly over Flint and inspect the devastation through the window. twitter.com/nytimes/status…
2016
04.10
04.10
Via reddit. North Korea is a horrible dictatorship where you only get to pick one person as a leader, not like the US where we get two.
2016
04.06
04.06
Student that got into all ivies. I suggest a reality show “the Bachelorette” following her as she choses the one.
nyti.ms/1MSRmPp
2016
03.31
03.31
So, after 20 years I decided to jump from tcsh to bash. Happy I did – the way of bash is strange, but everything is answered in stack-exchange (to the point that I don’t even try to figure out how to do simple things – just search the web for it). Furthermore, it is a way better scripting language with functions and stuff, and also clearly it is more complete. Oh, and it is even coming to windows 10, natively, any day now.
2016
03.31
03.31
14% of Hispanics view Trump favorably. That sounds too high to me… washingtonpost.com/blogs/plum-lin…
2016
01.20
01.20
I put my talk from SODA 16 on youtube (the audio quality is not great, but whatever):
- Part I: The circle packing theorem.
- Part II: The planar separator theorem — the movie.
- Part III: Low-density and polynomial expansion graphs.
- Part IV: Local search and approximation algorithms.
- Part V: Hardness, thesis and open problems.
The slides are available here.
2016
01.17
01.17
So, creating a vector animation for talks, once you have a pdf with each page being a frame of the animation is not hard, see here for details.
The question remain, how do we generate such a pdf to begin with? One way is by using a drawing program. Ipe is a good candidate, but creating such figures can be tedious, to put it mildly. In some cases (and you might want to sit before reading the rest of this sentence) there is really no better alternative to… doing some real programming!
Luckily, there is a light graphics library, specifically Cairo, that is happy to output directly to pdf (or svg) files, generating true vector drawings – which are both small, and of higher quality than the “standard” bitmap output (yuck).
Of course, you might want to have an interactive program, with a window and stuff, and output to pdf/svg only when you are happy with the results. Cairo is happy to let you do that – the same drawing code can be used to output to the screen, or to a pdf (or svg). Once you have a pdf, you can easily convert the figure to ipe, and edit the figure directly (using pdftoipe).
As a demonstration of the above, here is the source code of an interactive program I wrote (that I used to generate the above figure). Its a C++ program for linux, using gtk, cairo, and CGAL (because life is too short to implement 2d point class yet again). If this sounds like many libraries one needs, on Debian/Ubiuntu this just requires installing the relevant packages (you would also need the pkg-config package — a nice programming tool). The program is self explanatory as far as what keys do.
And a final comment — to force cairo to output the current image to a new page in the pdf file, one need to use cairo_show_page.
2015
12.13
12.13
Word of the day: Trilateration.
en.wikipedia.org/wiki/Trilatera…
2015
12.12
12.12
Kung Fu fight between a man and a cow… youtube.com/watch?v=LxXjsQ…
2015
12.08
12.08
How could the ancient Greek mathematicians be so smart, and yet so stupid?
2015
11.26
11.26
Drinking the kool-aid… en.m.wikipedia.org/wiki/Drinking_…
2015
11.26
11.26
The Serial Swatter… mobile.nytimes.com/2015/11/29/mag…
2015
11.19
11.19
Red mercury – the WMD every self respecting terrorist should have. nytimes.com/2015/11/22/mag…
2015
11.15
11.15
The conference will be held in the very centre of Prague, Czech Republic, in the historical building Karolinum of Charles University. The date is 23-28th July 2016, which is immediately after European Congress of Mathematics.
More details here.
2015
11.12
11.12
iff according to dictionary: “IFF Identification, Friend or Foe: an electronic system for recognition of friendly aircraft, ships, etc.
2015
10.27
10.27
2015
10.27
10.27
A Flamingo’s Dream
by Aleksander Wat
Water water water. And nothing but water.
If only an inch of land! An inch of no-matter-what land!
To set one foot on! If only!
We begged the gods for that! All of them!
Water gods, land gods, southern gods, northern gods,
For an inch, a strip, a scrap of any kind of land!
No more than just to support a claw of one foot!
And nothing. Only water. Nothing except water.
Water water water.
If only a speck of land!
There is no salvation.
2015
10.25
10.25
“vilifications of the measurements” = “curse of dimensionality”.