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63 years
I was born on Wednesday, November 1, 1961 at 9:45 in the morning (CET). That
means that today, I will be 63 years according to the calendar and 23011 days
old. But how old am I really? The tropical year, the time that it takes for the seasons to return, is said
to be 365 days, 5 hours, 48 minutes, and 45.19 seconds. Yesterday, around
15:56:26 in the afternoon, it was 63 tropical years since I was born. But the
tropical year is shorter than the sidereal year, the time taken by the Earth to orbit the Sun once with
respect to the fixed stars, namely 365 days, 6 hours, 9 minutes, and 9.76
seconds. That means that, today at 13:22:14 it will be 63 sidereal years
after I was born. The average anomalistic year, the time taken for the Earth to
complete one revolution with respect to its apsides, is 365 days, 6 hours, 13 minutes, and 52.6 seconds. That means
that, today around 18:19:13 it will be 63 average anomalistic years since I was
born.
I have been using the C progamming language (and later C++) for more than 34 years, but today I
wrote something, I cannot remember having written before and it looks like a
'double' declaration of a variable:
extern int counter;
int counter = 0;
I am big fan of encapsulation and I like clean include files that hide
implementation details that are not necessary for the users of the functions
given in the header file. The implementation for a certain header file
depended on a global counter that I did not want to include in the header file
itself, but it needed to be incremented somewhere else and initialized to zero.
So, I wrote in that other location, the main file (containing the main
function):
extern int counter = 0;
And this resulted in a compile error, because you are not allowed to
initialize a variable that is declared extern. Next, I changed the
line into:
int counter = 0;
Now, I got a linking error saying that the other external definition (in the
C file implementing the header file that relied on the counter
variable) was not defined anywhere. This is because although it is defined in
the main file, it was not defined as extern and thus not visible on the outside
and thus becoming invisible for the linker that combines all the separately
compiled C programs into one executable. It dawned on me that if I would have
placed the extern declaration in the header file, it would have worked because
then during the compilation of both C programs it would have been defined as
extern and in the main program I still would have been able to initialize it.
Although it is not common to see a 'double' declaration in a C file, like the
above, and even looks a bit confusing, it is actually somthing that is done all
the time, because the C preprocessor put both declarations into the intermediate file that is
compiled by the actual compiler.
Colourful harvest
We got a rather colourful harvest from Herenboeren
Usselere Es and I took a
picture of a part of the harvest.
In this picture there are: a small puprple cauliflower, a romanesco broccoli,
a fennel, two red cabbages, a green and a orange pumpkin, and a leaf of curly
kale.
Book
At 18:40, I bought the book Prospects 2021: Mondriaan Fonds toont talent
edited by Mirjam Beerman, written in Dutch, and published by Het Mondriaan
Fonds in June 2021 from thrift store Het Goed
for € 1.00. Before I there, I went to thrift store Rataplan. Although it seems they have more books there, I
get the impression that they sell less books. These trift stores are for
profit shops.
Cubes from Sheet: 11 by 11
I have this feeling that there are solutions for all cubes from a sheet problems, where at least one piece can be placed into,
exists where at most twelve squares are unused for cubes. In the past weeke, I
have been searching for counter examples. The program that I used, took a long
time to find a solution with less than thirtheen unused squares for a square of
eleven by eleven squares. Yesterday, I modified my Exact Cover program to also support positions with multiple vectors. This
is a generalization of the Exact Cover problem. The multiple positions are needed to restrict the
number of unused squares to an exact number. When I tried this program on the
elven by elven square with seven unused squares, it found some solutions within
half an hour. The first solution it found was represented as (on a single
line):
S0_1_2_13_14_15|S3_4_5_16_17_18|S6_7_8_19_20_21|e9|e10|E11_12_23_24_25_36|E22_33_34_35_46_47|W44_45_56_57_68_69|W55_66_67_78_79_90|E77_88_89_100_111_112|e99|e110|D31_32_40_41_42_52|e30|W43_53_54_63_64_74|W65_75_76_85_86_96|E87_97_98_108_118_119|e109|e120|A28_29_38_39_50_61|Z26_27_37_48_58_59|S51_62_72_73_83_94|S49_60_70_71_81_92|K80_91_101_102_103_113|A82_93_104_105_114_115|A84_95_106_107_116_117|
This evening, I checked this solution and made the following drawing of it:
+--+--+--+--+--+--+--+--+--+--+--+
| | | |##|##|
+--+--+ +--+--+ +--+--+ +--+--+
| | | | |
+--+ +--+--+--+--+--+--+--+--+--+
| | | | |##| |
+ +--+--+ + +--+ +--+--+ +--+
| | | | | | |
+--+--+ +--+ +--+ +--+ +--+ +
| | | | | | | | |
+--+ +--+--+ + + + +--+ +--+
| | | | | | | | |
+ +--+ +--+--+ +--+ + +--+ +
| | | | | | |
+--+ +--+--+ +--+ +--+--+ +--+
| | | | | | | | | |
+ +--+ + + + + + + +--+ +
| | | | | | | | | |
+--+ +--+ +--+ +--+ +--+ +--+
|##| | | | | |##|
+--+ +--+ +--+ +--+ +--+ +--+
|##| | | | | |##|
+--+--+--+--+--+--+--+--+--+--+--+
I plan to refactor the code of my Exact Cover program such that it can be
more easily be called from the program finding solutions for the Cubes from
Sheet problems.
Bonnefanten Museum
Conny and I visited the Bonnefanten Museum in Maastricht. We first went to see the exhibition Maintaining Its Spirit: Collection Marlies & Jo Eyck at Bonnefanten.
I found the following works noteworthy to mention:
- Untitled, Rob van Koningsbruggen, 1977.
- Cluster no. 16, Peter Struycken, 1971.
- Cluster no. 2, Peter Struycken, 1971.
- KTV1T.852, Peter Struycken, 1983.
- POS 18F, Peter Struycken, 1985.
- KTV kleur, Peter Struycken, 1978.
- Lnarc, Peter Struycken, 1973.
- Structuur XXXIII, Peter Struycken, 1967.
- Kleurstructuur voor bedrijfspand J. EYCK 1e Roermond, Peter Struycken, 1977.
- KTV kleur, Peter Struycken.
- 090373-1B (Plons), Peter Struycken, 1973.
- Field 47, Peter Struycken, 1979.
- Shft 25, Peter Struycken, 1983.
- SIM, Peter Struycken, 1987.
- Shft 34, Peter Struycken, 1986.
- Boulez/45k/20nov04/06-maa/28.bmp, Peter Struycken, 2005.
- Some Natural Aspects of Sculpture, Ger van Elk, 1972-2002.
- She loved her madly, Jarostaw Fliciński, 2005.
- 71-36, Jan Schoonhoven, 1971.
- Untitled, Ben Akkerman, 1983-1984.
- Wand II, Amédés Cotrrer, 1970.
- 2T, Donald Judd, 1971.
- Dubbelschilderij, Bob Bonies, 1968.
- Computerstructuur 69-II, Peter Struycken, 1969.
- Houtgrafiek nr VIII, Ad Dekkers, 1970.
- Stad, Ad Dekkers, 1960.
- Zeshoek en ruit overgang, Ad Dekkers, 1967.
- Cirkel op de middellijn omgezet, Ad Dekkers, 1968.
- Untitled, Ewerdt Hilgemannn, 1973.
- Untitled, Bart van der Leck, circa 1928.
- Serie A,B,C,D,E,F, Right Hand Left Hand, Kenneth Martin.
- square grid - complexities, herman de vries, 1975.
- Gitter, François Morellet, 1962.
- Untitled, Chris Beekman, circa 1945.
- Zwart Wit, Amédé Cortier, 1972.
- nKM V, Carel Blotkamp, 2006.
- The space between you and me, Keith Edmier, 2000.
- Tschlin, Curdin Tones, 2005.
- Far from the madding around , Dan Asher, 1996.
- On a night like this II, Mathilde ter Heije, 1998.
- Kleine Pneuma, object no. 14, Robert Lambermont, 2001.
- Regen, Carel Visser, 1985.
From the exhibition Stanley Donwood and Thom Yorke: Maps of the New World I liked:
- Unchecked, 2022.
- A Map of the New World, 2024.
From the exhibition Małgorzata Mirga-Tas: This is not the end of the road, a solo
exhibition with works by Małgorzata Mirga-Tas, I found the following works to be noteworthy:
- Phenia - Sister, 2024.
- Basiawiben predale baba - Music for grandmothers, 2024.
- Roziena kiereta babakie sinkar hajtań - Roziena brushes her grandmother's beautiful hair, 2024.
- Portrait of Lalla Weiss, 2024.
- Re-Enchanting The World, a series of twelve works, which we both
found the most impressive of what we saw on this day:
- January 2022
- February 2022
- March 2022
- April 2022
- May 2022
- June 2022
- July 2022
- August 2022
- September 2022
- October 2022
- November 2022
- December 2022
- Out of Egypt, 2024.
- Out of Egypt, 2024.
From the exhbition Dream On, I found the following works noteworthy:
- A Map of Days, Grayson Perry, 2013.
- Untitled (Master of the Universe, Lee 'Scratch' Perry, 2018.
- Mommy, Sofiia Dubyna, 2023.
- Dianaland, Sofiia Dubyna, 2023.
- Diana's Monkey, Sofia Dubyna, 2023.
- Pee on Presidents, Melanie Bonajo, .
- Eight drawings, Sandra Vásquez de la Horra, 2007.
From the exhibition Collection Neutelings, I found the following
painting noteworthy:
- Still Life, Henri de Fromantiou, circa 1670.
- Portrait of a Couple or a Mother and Son, Cornelis de Vos, 1600-1650.
- Family Portrait, Pieter Isaacsz, 1609.
- Census at Bethlehem, Pieter Brueghel Jonge, ca. 1605-1610.
From the exhibition Truly Wicked: The Seven Deadly Sins visualised, I found the
following works noteworthy (I was getting a bit tired and filled with images):
- Herbergscène, Helen Verhoeven, 2017.
- Church I, Helen Verhoeven, 2017-2018.
- Tavern Scene, Monogrammist van Bruuswijk, circa 1535-1540.
- The World in Good Standing, Anonymouse, circa 1570.
- Allegory of Lust / Lascivia, Abraham Jansens van Nuyssen, circa 1618.
Furthermore, we walked through Studio Rossi with design of the museum
building and walked around The Shooting at Watou by Folkert de Jong.
After we visited the museum, we walked through Maastricht taking some pictures.
We brought a short visit to the bookshop Boekhandel Dominicanen, which I
visited before on Sunday, July 21, 2019. It was
already dark, but we took some pictures from the Sint Servaasbrug (a bridge over the Meuse river) before went to the
Indonesian restaurant KapuláGa were we had the Kakanda rice table, which existsed of
yellow yice, daging balado, rendang, smoor, ayam pedas, ayam opor, sate ayam,
sambal goreng udang, tempe, poached egg, sayur lodeh, seasonal vegetables, gado
gado, atjar, seroendeng, roedjak. We had some strawberry ice as an desert. We
were very satisfied with the dinner.
Wijlre
On the way Wijlre Conny and I stopped at the
Netherlands American Cemetery and Memorial located in the village of
Margraten and waled around the cemetery. We thought about the many soldiers
that died during the liberation of Europe from the German occupation and how
this relates to the current war in the east of Europe. We did like the design
of the chapel with the window on the side.
Close to noon, we arrived at Kasteel
Wijlre Estate for the exhibition
Maintaining Its Spirit:
Collection Marlies & Jo Eyck. I found the following works noteworthy:
- Color space generator Eyck, Peter Struycken, 1999.
- 1.5 kwadraat, reliëf met anderhalf vierkant, Ad Dekkers, 1969.
- Untitled, herman de vries, 1977.
- TAP2 TAPW5, Peter Struycken, 19880-12-02.
- Claie obscure, Carel Blotkamp, 2002.
- From Cube to Cylinder, Ad Dekkers, 1968.
- Untitled, Leo Vroegindeweij, 1993.
- Kleuren van Tuinhuisje naar Goudreinet appel, Peter Struycken, 1993.
- Salami, Carel Visser, 1964.
- Broken Circle, Ad Dekkers, 1971.
- Pathway Tree and Bronze Tree, Giuseppe Penome, 1197.
- Piet 5, Peter Struycken, 1984.
- Afstemming IV, Peter Struycken, 2020.
- Dots 81 mimosa, Peter Struycken, 1981.
- Untitled, Richard Paul Lohse.
- Jacquard geweven wanddecoratie, Peter Struycken, 2008-09.
- Plant-Based, Carel Visser, 1989.
We also saw the exhibition Growing Poetics by Thierry Oussou. We in particular liked the La Poessie in one of the
rooms in the attic that he had filled with branches he found on the estate.
On the way home we stopt at the McDonalds in
Drosten were we ordered two McPlant meals consisting of a plant based burger
with french fries and a cola. This is at least the third time I visited this
McDonalds. I visited it on Saturday, September 22,
2018 with Andy and on Friday, July 29, 2010
with Li-Xia.
Exhibitions
After work, I went into the city where I visited the exhibitions at Concordia. I saw the following exhibitions:
- Joystick by Madison
Bycroft. I played a bit with the game but I got into the water and had
some trouble getting out of it. I did not know how to exit the game. This
exhibition is part of the Overkill Festival.
- Doublet #6: Kira Fröse and
Marthe Zink. I felt
that they really succeeded into make cohesive exhibtion when combining
their art works.
- The Artist's Way with works by various mothers following the book
The Artist's
Way by Julia Cameron. There were some series of works that really stood
out.
- It Gets Better by Tim Vischer.
- Ik kom er nu nog gewoon even echt niet uit by Björn Zielman.
Book
At 17:05:15, I bought the book HETHE BESTE VAN OF
WIM T. SCHIPPERS written by Harry Ruhé in Dutch and English, and
published by Centraal Museum in 1997, ISBN:9789073285446, from bookshop Broekhuis
for € 45.00. This is a bilingual edition where the Dutch text is
printed in red and the English text in green on top of each other. To read the
text a transparent green and red sheet is provided in the front of the book
that you have to put over the text. This book is the catalogue of
an exhibition of the same name.
Harvest
Below a picture of the harvest
(except for the 2 kilogram potatoes) that we received this morning from Herenboeren Usseler Es. (What you receive depends on how many 'mouths'
you are paying for and personsl choices you make.)
The picture shows:
- A bag with 2Kg of rye flour
- Two red chicories
- A savoy cabbage
- A cauliflower
- Two delicata squash
- Some lacinato kale
In the evening, I made some stamppot with the lacinato kale, two small red unions, a yellow bell
pepper and some sauerkraut bacon. Conny made
a salad with the outer leaves of the two red chicories.
Cooperative, polling operating system
I have been thinking about a tiny cooperative and polling real-time operating system that works with static, single instance tasks.
ESP-IDF is based on FreeTROS, a real-time operating system for embedded devives. Although
FreeTROS is called real-time, it has some dynamic behaviour due to dynamic
memory allocation and interrupts. Nowadays, many peripherals are connected
through serial
communication busses, such as SPI, I2C, and I2S, where there are often
multiple slave peripherals are connected on a bus. These peripherals often have
complex operating modes that can be adjusted through control registers, and
possibly also complex behaviour patterns. This has an impact on the real-time
behaviour of microcontrollers that communicate with these peripherals. If you
do not want to use interrupts, it means you have to use polling to see if an
interaction with a peripheral has completed. If you develop an application that
interacts with several peripherals, it is logical to have some kind of layering
in more device oriented tasks, coordinating tasks, and more high-level tasks.
If you do not use operating system like functions like queues, this results in
tasks polling the completing of lower-level tasks. To avoid excessive polling,
which takes a lot of resources, I have been thinking about a number of queue
based approaches to avoid polling. Tasks often make use of finite-state machines, which are usually implemented with case-statements.
If these are not compiled to branch tables they performance is lineair to the number of cases. To work
around this, one could use functions for each of the states and cause the right
function to be called for each state. This does match with the idea of tasks. I
have started writing some code as an experiment:
TinyCoPoOS.c. I also have been thinking
about program generating the code for all the functions given a tasks
declaration.
In the afternoon, I helped a bit with the planting of fruit trees at
Herenboeren Usseler Es. When I arrived the others
just were taking a break, because some of them already started at nine in the
morning. I mostly dug holes at the places where a tree had to be planted.
Twice we had some rain. The first time with some hail and at 14:30, there was a
rainbow. I am looking forwards how the trees are
going to grow in the coming years.
Wet snow
This afternoon, for some hourse there was wet snow
falling from the sky. While it was snowing, some of it stayed on the grass
a bit Still would not count this as snow. During the period it snowed, the
temperature dropped to almost zero degrees Celcius.
Snow
This afternoon, it snowed again and this time stayed
on the grass and on cars. I estimate that at least 1cm of snow fell. The snow
that stayed did not melt away in the evening, like it did yesterday.
This months interesting links
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