<![CDATA[My Blog]]> https://www.jure-smolar.com/ Thu, 09 Apr 2026 16:55:11 +0200 <![CDATA[Links for March 2026]]>
  • China's Parents Are Outsourcing the Homework Grind to A.I.
  • Cave Story: A Lyrical Walkthrough (Full Vid) - CaveStoryRap
  • Wolves and Ravens: Nature's Best Friends - YouTube

  • Collections: Warfare in Dune, Part II: The Fremen Jihad – A Collection of Unmitigated Pedantry

    That position – that the destruction of the Fremen Jihad is not merely possible but inevitable to the point that Paul cannot stop it – puts a very, very high bar on its military plausibility. In particular it rules out any defense that Fremen victory is simply because Paul, as a prescient military leader, can simply pull an endless series of ‘inside straights.’ Remember: the Fremen explicitly still win even in Paul Muad’Dib Atredies [sic] is dead at the hands of Feyd Rautha Harkonnen. It is not enough for it to be possible for the Fremen to win, it must be impossible for them to lose.

    Now in the thematic world of Dune, that is because military victory is fundamentally a product of the Fremen Mirage: societies have an inherent vitality to them and the Fremen are vital, hardened by the harshness of Arrakis, in a way that the Great Houses are not. In Herbert’s mind, that is enough: the ‘hard men’ created by the ‘hard times’ of Arrakis will inevitably triumph once an event – the emergence of Paul as a heroic figure – spurs them into action. Paul is thus die Weltseele zu Pferde, “the world-spirit on horseback,” the archetypal ‘great man of history’ who embodies supposed historical forces which are larger than him, which act through him and which would act without him.

  • Mineral Commodity Summaries | U.S. Geological Survey

    Published on an annual basis, this report is the earliest Government publication to furnish estimates covering nonfuel mineral industry data. Data sheets contain information on the domestic industry structure, Government programs, tariffs, and 5-year salient statistics for over 90 individual minerals and materials.

    It's insane, in a good way, that something like this is publicly available for free. A breakdown of US and global mineral production stats. They give both a general overview and then a breakdown for each of the 94 tracked minerals. Wow.

  • Mining For Beginners - How Does a Metals and Mineral Mine Work? - Energy and Mining Innovation

    So fucking Factorio.

  • Saw | ContraPoints - YouTube

    This is why she's still the fucking goat. I tend to prefer her more abstract pieces, like Twilight and (especially) Envy so I had a great time.

  • SymbolicsGenera (Official Symbolics Ivory Emulator) · GitHub

    For a few days in March, the official Symbolics Genera organisation contained a repository named Licensing which had a (draconian) "friends of lisp" contract one could sign to get access to the Genera source. It seems to be gone now. Sadly I failed to archive the PDF. It was quite funny with, for instance, a clause noting the necessity of deletion of all Genera software from your computers upon death. I ended up not applying, mainly because the process involved typing one's full address into the Github issues tracker. We'll see if they put together anything less restrictive.

  • GitHub - hanshuebner/lisp-mcp · GitHub

    Seems to have been renamed from genera-mcp. Maybe the restrictive license? This guy was the first to get in to the aforementioned program. Happy hacking brother.

  • Britain Still Has Conversion Therapists. Here’s Why - Philosophy Tube

    A superb look into the history and (tragically) the present of conversion practices. Definitely worth a watch.

    The interested watcher can find an even deeper dive in Debunking Transphobia of JasperDasper. It's been a while since I saw it so I do not recall the overlap.

    "It was never about helping people. It was always about authority." [~31:00]

    "The state of mind has been replaced by the Cass Review. A nice clean document that produces that moment of disconnect between what folks working in the NHS believe they are doing and what they are really doing." [~1:59:00]

    (re: Hilary Cass's BBC interview, Feb 2026): "This is the same false theory that justified abuse and conversion practices on queer kids in the 1950s. It is very worrying that a woman presented by British media and politics as an expert on our healthcare was allowed on the BBC to rehash unchallenged the 75-year-old nonsense of a dead pedophile." [~1:44:00]

  • Miscellanea: The War in Iran – A Collection of Unmitigated Pedantry

  • Apple Vision Pro’s Optics Blurrier & Lower Contrast than Meta Quest 3 – KGOnTech

    This is quite a niche post, balanced out by the interesting and quite unexpected fact it talks about. As said in Vision Pro is an over-engineered “devkit” (emphasis mine):

    With this design decision, Apple is no doubt giving up a bit of the Vision Pro display’s high pixel resolution in order to achieve overall smoother graphics. You are definitely losing some text crispness in order to gain a higher perception of quality for images, video and 3D animations. This is a big benefit of starting with an ultra high-resolution micro-OLED display — Apple had enough pixels to work with that they could afford to make this trade-off. This is the kind of thing that our hardcore VR engineers at Oculus would have fought against to the end of the world, and I doubt we could have ever shipped a “blurred headset”, LOL!

  • The easiest way to make the world smarter - Rabbit hole

    A history of iodine deficiency and supplementation. A somber reminder that the world we know is not an immovable thing but a process that must be kept in motion continuously by many sober hands. See also The World Keeps Getting Saved and You Don’t Notice (TW: LessWrong). Our safety makes us forget. A similar trend in the eradication of diseases like polio is a necessary component for modern vaccine skepticism. Like one can assume there's no need for iodine in salt because there are no goiters to be seen, one has the privilege of assuming that vaccines either don't work or are simply a tool of the deep state or whatnot. These sorts of things feel like the closest thing there is to a genuine luxury belief.

  • Destroying A World That Doesn't Exist - Wifies

    The sequel to one of the candidates for the best Minecraft video of 2025, Searching For A World That Doesn’t Exist, a cross between the genres of an ARG analysis video, an ARG in itself and a creepypasta. The sequel is bombastic, a perfect continuation with, most notably, completely breathtaking set design, i.e. builds. Back in the day, even a small part of one of these would have been a jaw-dropping video to be shared for months. The level that we got to is incredible.

    • Tags: links
    ]]>     https://www.jure-smolar.com/2026-03-links.html https://www.jure-smolar.com/2026-03-links.html Tue, 31 Mar 2026 00:00:00 +0200     <![CDATA[Unija z rangom]]> A test post from my old notes. The content is not very well written or well-organised, but it has both a code block and \(\LaTeX\), so serves as a good test for the site's features.

    Operations:
    • singleton(x) . ustvari singleton \(\{x\}\)
    • find(x) . poišči predstavnika komponente, ki vsebuje \(x\)
    • merge(x, y) . združi komponenti/množici, v katerih sta \(x\) in \(y\)

    Unija z rangom

    Množice prestavimo z DAG, kjer gre iz vsakega elementa natanko ena povezava Potem ima vsaka komponenta natanko en ponor.

    To shranimo z dvema tabelama, v eni imamo predhodnik od vsakega elementa (če je v enojcu je sam svoj prednik), v drugi pa rang elementa.

    Lastnosti ranga za union-find
    1. rang(x) < rang(π(x)), če x≠π(x).
    2. Če je \(x\) ranga \(k\), ima \(x\) pod sabo vsaj \(2^k\) vozlišč (vključno s seboj).
    3. Če imamo \(n\) elementov, imamo lahko največ \(\frac{n}{2^k}\) vozlišč ranga \(k\).
    4. Sledi, da je maksimalen rang lahko \(\log n\)

    Primer:

    Vzemimo \(\{A,C,D,F,G,H\}\) in \(\{B,E\}\).

    Tabela:

    x A B C D E F G H  
    π(x) F E H H E H D H <- Predhodnik
    rang(x) 0 0 0 1 1 1 0 2 <- Globina drevesa pod x

    Operacije:

     
    from functools import reduce

π = {}
rang = {}

def singleton(x):
      π[x] = x
      rang[x] = 0
      return x

def find(x):
      while x != π[x]:
          x = π[x]
      return x

def find_amortized(x):
      "Na vsakem koraku malo flattenaj"
      if x != π[x]:
          π[x] = find_amortized(π[x])
      return π[x]

def merge(x, y):
      p_x = find(x)
      p_y = find(y)
      if p_x == p_y:
            return p_x
      else:
            if rang[p_x] > rang[p_y]:
                  π[p_y] = p_x
                  return p_x
            else:
                  π[p_x] = p_y
                  if rang[p_x] == rang[p_y]:
                        rang[p_y] += 1
                        return p_y


  # Primer od prej:

  #for el in ["A", "B", "C", "D", "E", "F", "G", "H"]:
  #    singleton(el)
  #reduce(merge, ["A", "C", "D", "F", "G", "H"])
  #reduce(merge, ["B", "E"])

π = [0,0,1,3,3,4]
rang = [2,1,0,2,1,0]

print(π)
print(rang)

find_amortized(2)

print(π)
print(rang)


    [0, 0, 1, 3, 3, 4]
[2, 1, 0, 2, 1, 0]
[0, 0, 0, 3, 3, 4]
[2, 1, 0, 2, 1, 0]

    Načeloma singleton in merge ne rabita vračati, to je le zavoljo primera, saj lahko s tem uporabimo reduce za konstrukcijo množice. Rezultat se razlikuje od zgornje postavitve, ker več DAG-ov predstavlja isto množico. Če se drevo nariše, se jasno vidi, da množici predstavljata isto particijo.

    Zahtevnosti:
    • Singleton: \(O(1)\)
    • Poišči: \(O(\log n)\)
    • Amortiziran poišči: \(O(\log^*|V|)\)
    • Združi \(O(\log n)\)

    Z izboljšavo dobimo amortizirano časovno zahtevnost.

    Opomba:

    Z uporabo amortiziranega poišči je tudi združi amortizirane časovne zahtevnosti (saj je le dva poišči in nekaj konstantnih operacij).

    Union-find with path compression

    Back

    Koliko nas stane paket \(m\) operacij poišči na \(n\) vozliščih?

    • \(\log^*n\) - kolikokrat moramo zaporedoma narediti logaritem, da pridemo na 1 ali manj.
    • \(\log\log\log\log 1000 \leq 1 \implies \log^{*}1000 = 4\)
    • Poišči nas stane v povprečju \(O(\log^{*}n)\)
    • V resnici bi zaporedje \(m\) operacij stalo \(O(m\log^{*}n) + O(n\log^{*}n)\).

    Rang se ohranja, a ne predstavlja več globine drevesa. Range razdelimo na intervale: \[ [1], [2], [3, 4], [5, 16], [17, 2^{16}], [2^{16} + 1, 2^{2^{16}}], \dots \] Ko vozlišče ranga iz \([k + 1, 2^k]\) neha biti koren, mu damo žepnino \(2^k\) žetonov. En žeton porabi en skok po povezavi. Vozlišč iz tega intervala je največ \[ \frac{n}{2^{k+1}} + \frac{n}{2^{k+2}} + \cdots + \frac{n}{2^{2^k}} \leq \frac{n}{2^k} \] Vsak interval dobi največ \(n\) žepnin. Intervalov je največ \(\log^{*}n\). Operacija poišči(x) porabi toliko, kot je dolga veriga: \[ x = y_0 \rightarrow y_1 \rightarrow \cdots \rightarrow y_r \] Vrednosti \(\rang(y_i)\) in \(\rang(\pi(y_i))\) sta lahko ali v različnih intervalih, kar se lahko zgodi le \(\log^{*}n\)-krat, ali pa v istem intervalu. V tem primeru \(y_{i}\) prispeva en žeton, s čimer smo povečali \(\rang(\pi(y_i))\). V kombinaciji z večimi združi se to lahko zgodi kvečjemu \(2^k\)-krat, saj je vozlišč največ \(\frac{n}{2^k}\). Torej imamo dovolj žepnine.

    ]]>     https://www.jure-smolar.com/20211125173234-union_find.html https://www.jure-smolar.com/20211125173234-union_find.html Wed, 02 Feb 2022 00:00:00 +0100