I write, therefore I am
With this variation on a famous statement by the philosopher Descartes, I would like to express that the act of writing about what happens in my life is important to me.
Dead end?With the results of last Sunday, I tried to find the 35 constant weight vectors for A(11,4,4) as mentioned in a table. I did this by starting with the 54718 solutions consisting of 19 vectors and try to extend it further. The program found 46080 solutions (possibly containing doubles and missing some) consisting of 30 vectors and non with more than 30 vectors. It looks like a dead-end. Which actually does not surprise me, because requiring that 18 vectors will be close to one vector, might force them to be spread apart too far and in a some what regular manner, that no space is left over to select the remaining sixteen vectors from.
Thursday, September 19, 2019
Tuesday, September 17, 2019
54718 solutionsI continued working on the program to calculate the number of different solutions of 18 constant weigh vectors 'around' a vector with seven ones and four zeros, where around means at a Haming distances of four and such that all vectors are at distance of at least four. The program found 54718 different solutions taking in consideration all possible permutations of the 'rows' of the vectors.
TetemI went to Tetem art space to look at the exhibition Xenobodies in Mutation. At the Exploring-Lab some people were assembling a small motor powered by solar cells. I also joined and assembled one.
BookI recieved the book Kilo-Girls written by Julia Luteijn in English, which I bought from the author for € 13.90 (including postages).
1773 constellationI continued working on the 18 vectors problem (which is related to the KABK wrapping paper) and this evening, I worked on a program to calculate the number of unique ways the octahedron can be tilled with the 19 patterns I found on September 1. I arrived at a program which calculates in how many ways the edges can be marked with on of the three possible patterns, such that they are compatible with the 19 patterns. Such a 'constellation' does not neccessary match a solution of the patterns and even if it does, there could more than one. The program found 1773 such constellations. When at home, I thought about a different approach for finding the solutions for the 18 vectors problem.
GogbotI was a guard at the former VVV-building. The first half on the second floor and the second half on the third floor. These floors had all the Young Blood nominees, selected from the graduates of the various art academics in the Netherlands. I found the following nominees mentionable (roughly in the order I encountered them at the exhibition):
The building also had the projects by the freshman students of the Creative Technology major of the University of Twente. I used the Embry-o-'matic to 'create' a designer embryo from Stork Industries. Mine was #10293 and I had to 'pay' $4929. In the evening, I again, helped out at the Oude Kerk, because some volunteers wanted to have dinner and one did not show up (or left early).
the Gogbot festival, we saw a rather bright, double, and complete (as far as I could see) rainbow. I took several pictures, one of which is shown to the right. After the opening, at eight, I helped out as a guard in the Grote Kerk because there were a lot of visitors. I stood near the entrance, close to The Mictobial Vending Machine by Emma van de Leest, one of the few artist being present at the exhibition in this location and explaining her project to visitors. Also close were the Pink Chicken Project, Al¿ve, and Caravel. There was not much interaction or moving projects as in some of the previous years and several vistors commented about this to me while leaving the venue. At eleven, after the exhibition closed, I went to the Metropool concert room to have a peek at the Gogbot lift off // Experimental Electronics & Modular Night, which was free for volunteers, only to discover that they had very strict rules with respect to bags and coats, and that the small lockers costed two Euro each. I was a little disappointed, because I had hoped to work a little on my notebook while listening to the music, and decided to go home.
GranduncleToday, my mother became a great-grandmother, because the oldest son of my youngest sister became a father. It also means that I have become a granduncle.
18 vectorsYesterday, while guarding the entrance for the retro game day, I looked at the problem of finding at the 35 vectors. I have been looking at finding collections of eighteen vectors at the Haming distance of four from a vector. The reason why there are eighteen is because there are only six ways to change two of the four zeros into ones and at most three non-overlapping pairs of ones that are changed into zeroes. I realized that there are some restrictions as to how for three patterns of zeros that are changed into ones that only differ at two locations, such as for example, 1100, 1010, and 0110, the way the ones are changed into zeros must all be different. Because if they are the same, the Haming distance is only two. I got the idea that there were only four configurations, not counting all kinds of symmetries. But when I was at home, I wrote a program, which produced 19 solutions. Which meant that either I was wrong or the program. Today, I wrote the following animation to display the 19 solutions. The three colours refer to the three ways in which zeros are changed into ones and the three lines refer to the patterns in which the ones are changed into zeros. Any of the 21 possible lines cannot have two colours and there cannot be a point where to lines of the same colour meet.
In the evening, I realized how there eight combinations of three vectors, such as in the example, and that these can be visualized as the triangles of the octahedron. And also that each edge represents the lines of two colours and that there are only three possible patterns of these, namely, where the lines are a cycle of six lines, a cycle of four lines and a path of two lines, or a path of six lines. This put a lot of restrictions on how the various patterns can be placed on the octohedron, and that that is a good way to determine all unique (with respect to symmetries) combinations of 18 vectors there are.
Retro gaming dayI helped out at the retrogaming day at TkkrLab.
HeatwaveToday, the heatwave, which started on August 22 (locally) and on August 23 (nation wide), has been terminated. It was the 28th national heatwave on record. Last night there were thunderstorms and some heavy showers. Today, the temperature reached 24.5°C. The maximum temperatures in the past days (at the Twente Airport weather stations) were: 25.8°C (22), 26.6°C (23), 30.0°C (24), 31.1°C (25), 32.6°C (26), 33.3°C (27), and 30.9°C (28).
BadgesTonight at TkkrLab, I received two badges: the CampZone 2019 badge and the card10 badge from the CCCamp 2019. I made some donations to the Badge Team for both of them. The second is not really a badge, but a smart watch with a Cortex-M4F core.
AmsterdamI went to Amsterdam. At 13:40, I bought the following two books from bookshop Scheltema:
ZomergoI attended Zomergo, a rather relaxed Go retreat, for three days and two nights. I won two out of three games. Today, I joined in a round-table teaching session, where Lazy Baduk, also called Lizzie, which uses a network based on results from Leela zero, was used to make an odd number of participants. It was also often used to evaluate the current board. I understand that many people are using it to review their games.
Constant weight codesWhile thinking about the KABK wrapping paper, I arrived at constant weight codes through error correction codes. The Hamming distances of two line patterns of a logo is equal to the places where there is or is no line. Thus moving one line, equals a Hamming distance of two. To avoid these the distance should be 4 and for logos with six and seven lines, we should look for the value A(11,4,5) and A(11,4,4) respectively. According to a table, these values are 66 and 35. There is a superscript s with the 66, which stands for: "shortened code (from code of length n+1 and weight w or w+1)." I downloaded the data for A(12,4,5) and wrote a small program to convert it into binary vectors, but I have no clue how to shorten the vectors into something useful. It seems I have to write a program myself to generate the vectors. exhibition AKI Graduates at photo gallery Objektief with works from three female graduates of this year, namely: Noor Lorist, Leanne van der Wel, and Emmy Muijstege. I cannot remember having seen the works of Leanne.
KABK wrapping paper alternativeI wonder it would be possible to arrange the logos in the KABK wrapping paper such that logos that have similar lines added are not placed close together. I wrote a program, which basically exchanges two at random selected logos as long as it does not make things worse, and continues with this until there is nothing to improve anymore. It makes use of a badness measurement that defines when the line pattern of two logos are to similar when logos are a certain distance of each other. Also mirrored logos in close proximation are considered bad. The solution the program came up with can be found in this PDF. I want to investigate if there are alternative selections of logos that by themselves are less 'close'.
Third qualifying round (continued)Gerard, the one who raised the question about the third qualifying round, figured out the mathematical formuleas behind the problem. (In the following, I will use the n over k notation for binomial coefficient n!/(k!(n-k)!).) First he derived the expressions for the numbers produced by the program I wrote:
11520 = (10 over 0)(10 over 2)2^8 53760 = (10 over 1)( 9 over 3)2^6 50400 = (10 over 3)( 8 over 4)2^4 10080 = (10 over 4)( 7 over 5)2^2 210 = (10 over 5)( 6 over 6)2^0Next he generalized this to the expression:
(w over s)(w-s over s+w-t)2^(t-2s)Where s is the number of games in which two 'League Path' teams play against each other, t is the number of 'League Path' teams, and w is the total number of games played, which equals half the sum of 'Champions Path' and 'League Path' teams.
KABK wrapping paperIn the past week, I spend some time to analyze the wrapping paper of the Royal Academy of Art (Koninklijke Academie van Beeldende Kunsten in Dutch, KABK for short), which I took with me when I visited the graduation exhibition on Sunday, July 7, 2019. The wrapping paper is based on logo of the KABK, which consist of seven dots, four dots in a square, one dot in the middle of the top two dots, and two dots at the cross points of some lines between the other five dots. The seven dots can be connected with seven lines to create the shape resembling a crown. On the wrapping paper, there are 27 lines 18 columns of these logos, with seemingly randomly added lines between the dots. On the seventeenth row in the eleventh column, the logo resembling a crown can be found. I took a picture of the wrapping paper and analyzed this with a MySample script to extract the lines used in each of the logos. I next went on to analyze it with a program to see if there is any pattern in the lines added to the logos. I discovered that the first ten columns all logos have six lines added, and that in the remaining eight columns, all logos have seven lines added. There were no two logos with the same lines added. Futhermore, I could not find any patterns. It seems that the logos are purely selected and also placed at random. The design somehow reminds me of the PARR patterns, who were designed by Taconis Stolk, who at the moment is the head of the ArtScience department.
Monday, August 4, 2019
BookshopsI went to Amsterdam, to see the graduates exhibition at gallery Ron Mandos, but they were closed, due to canal pride. I visited the following bookshops in Amsterdam and Utrecht:
Received two booksI recieved the two books from Antiquariaat Kas Cornelis, for € 6.00 each:
-- contact -- Frans
My life as a hacker
The Art of Programming
HTML to LaTeX
eXtreme Programming Programs Hamilton cycles
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