Bellende Hunde jede Stunde, von Sekunde zu Sekunde reist der Geist von wach zu schlaf. Zu wach: Ein lauter Krach, der Nachbar schließt laut seine Tür – ohne jegliches Gespür. Ich mach das Dach zu und lieg flach im schwülen Bus, jetzt fehlt frischer Luft-Zufluss: Fenster auf zum Kühlen. Schluss, jetzt wird tief geschlummert. Endlich leise, zeitweise. Vögel singen, paarweise, Ton-Gebilde in die Nacht. Milde Luft bringt feinen Duft von Regen rein, von wegen kein Wasser, es tropft und strömt, wir sind verwöhnt von einsamer Natur; pur, rund um die Uhr. Und in der Ferne helle Sterne, eine einzelne Laterne leuchtet mitten ins Gesicht, ihr Licht durchbricht die dunkle Nacht, unangebracht. Feine Glocken von drei Schafen, Wellen im entfernten Hafen – wir schlummern ein, so gut es geht, bevor der nächste Tag ansteht.
April 2022. We are leaving the eastern part of the Pyrenees behind us, driving South. After a day of climbing we are looking forward to taking a cold bath. We have chosen the lake ‘Llosa del Cavall’, one of the many reservoirs in Catalonia, as well as a parking space with the possibility to swim.
Of course, we have heard of forest fires in Spain. And droughts. And water shortage. Especially during the last hot summers. But the absence of water is simply not engrained in our minds. Yet. That’s why we didn’t even think about the possibility of an empty lake. Spain is currently in one of its worst droughts, endangering harvest and ecosystems alike. Most water is used for agriculture; but strangely, farmers are more concerned about possible water regulation laws than to irreversibly lose their most valuable resource as the land slowly degrades to a desert. This attitude might be coupled with their age, as it is expected that most farmers will go into retirement within the coming years, and there are no young people to replace them.
We are arrive at the reservoir – at least that’s what our navigation system says. Because the reality in front of our windscreen looks differently: No water in sight, just bare rocks. We check again if we entered everything correctly. We did, this must be the lake. But this lake is missing its very defining feature: Water.
We use water carelessly during daily life, as though it is an unlimited resource; because for most of our lives it indeed has been rather unlimited. During our ongoing trip this has changed. Water is not only scarce in Spain, but also in our camper van. While a single flushing of our toilet back home would have used 10 liters of water, we now live on around 8-10 liters a day, including everything. Of course this changes on an instant when visiting a campsite and taking a shower, but it puts things into perspective. When I read ‘The End of the Ocean’ by Maja Lunde a few years back, I didn’t particularly like it. But this seemingly dystopian story probably hit the nail on the head in describing one potential future scenario on the shortage of water in Europe. When consulting the latest IPCC report, the question is not if a future without water scarcity will come, but if we can adapt in time to cope with it adequately. But taking into account societies will to adapt to other problems of climate change, the answer seems regrettably evident.
After closer investigation we see some water after all. It’s deep below, inaccessible, and not suitable to bath in; but it’s there. At least for now, until everything will be dry in a few summers from now.
I thought I am good in farewells, maybe even experienced; after all, I was close to having my last farewell more than once. But apparently I am not. There is the saying that you only learn to appreciate something when it’s gone. I already appreciated our friendship while it lasted. And they say ‚distance does not separate’, but it does. And so, here we are, you will stay and I will go. The distance will separate us, and we will continue on our own paths. You made me feel at home, you made me feel happy, and you made me feel safe. Thank you.
One last normal week. Calendars are packed with appointments, preliminary goodbyes with friends pass by, and the farewell consolidates. The two of us are now alone, to experience exertion and delight. On one of our first nights, an older German gentleman leaves us with a simple piece of advice: “Seid lieb zueinander.” – “Be kind to one another.”
Family discussions are a precarious venture: Bogged down relationships and intimate bonds clash with a mutual lack of goodwill and little restraint in abrasively advertising ones beliefs. The ones you’re nearest to might be the ones who are the least likely to share your worries and fears. Or they might be the ones who possess a seemingly divergent set of values. Each advent of a disagreement triggers the same repeating patterns, and all ways forward appear to be blocked; like a wall of snow, smudging an unequivocal truth, close but unattainable.
We are slowly approaching the end of our walk. A walk on easy terrain. The vast beach is leading to the vaster sea. The certain becomes uncertain, the walk becomes a swim. We are leaving the comfort in exchange for new experiences, for memories expected to remain. Towards new shores, one sunrise after another.
--- algorithm (noun) ---
A well-defined procedure consisting of a finite number of consecutive steps. Often confused with its realization (implementation).
--- The Algorithm (proper noun) ---
A musical project that blends electronic music with progressive metal. Often confused with random noises.
--- algorithm (example) ---
def is_alive()
return flip_coin()
def life()
while(is_alive())
go_outside();
take_pictures();
persist();
decay();
Aren’t algorithms fascinating? Well-defined procedures that solve well-defined problems – often with the goal to find the most efficient solution. It’s the single most important thing that amazes me in computer science.
My most favorite problem in algorithmics is one of the most simple ones. Suppose you have a short word, let’s call it T. Additionally, a long text S is given. The task is to determine whether the word T is contained within the text S. Thus, we want an algorithm for a simple search! Suppose the word T contains n distinct characters; for example T = “alive” has a length of n = 5. Similarly, the text S has a length of m, for example, S = “The tree is alive.” has a length of m = 18 (including the spaces and the period).
The most simplest algorithm aligns T at the first position of S and compares all n characters of T to the first n characters of S, which requires n comparisons (in other words, for our above example we answer the question whether “alive” and the first five characters of S are identical. Hint: they are not). Afterwards, the word is shifted to the next position of S and the comparison is repeated. This happens for all m starting characters of S. The problem? This will take a total of m times n comparisons which already amounts to 90 comparisons for our little toy example.
But what other solution could there be? There are many. None of them are easy to understand (at least for me), but all are fascinating. The first one I learned was the KMP algorithm, which performs mind-boggling reuses of previously obtained information about differing characters. The fascinating part: It only needs (roughly) m + n comparisons! A speed-up that determines whether we are able to browse the internet or not, whether we can perform research on molecular data or not, and whether we can advance as a technological species or not. Algorithmic design makes or brakes today’s society (at least for now, until climate change kicks in – always end on a positive note, right?).
[…] Thus in the winter stands the lonely tree, Nor knows what birds have vanished one by one, Yet knows its boughs more silent than before: I cannot say what loves have come and gone, I only know that summer sang in me A little while, that in me sings no more.
‘What My Lips Have Kissed, And Where And Why’ by Edna St. Vincent Millay; Musical interpretation: Thus in the Winter, by Christopher Tin
Trees are wise and tenacious. They endure at the most inhospitable places and cling onto earth as if their life depends on it – because it does. Trees are deeply ingrained and reach high. They depend on the light of stars and the nutrients of soil. Trees are manifold and and full of character which allows them to oppose changing climates. Trees have volition.
The other day I went out for some photography, motivated to exploit the snow that was still lingering around and covered the landscape like a gentle blanket. Just a few days earlier I had finished my thesis and, thus, I felt a freedom I hadn’t felt in a long time: Not a single appointment for the whole day, no deadlines, no waiting E-Mails, no social obligations, no time constraints. Simply a whole day for myself – is this what retirement feels like? I was standing on a hill overlooking villages, fields, and forests as far the hazy conditions allowed. And as I was pondering about my day, I simply picked a distant tree and started walking. No GPS, no directions how to get there, I simply started walking until I reached this lonely, very distant tree. And it felt good.
Punkt im Dunkeln 