Oxford Union by Ciro Santilli 35 Updated +Created
University of Oxford study costs by Ciro Santilli 35 Updated +Created
As of 2022:
The median household income at the time was 31k[ref]. Clearly, putting one child through university with that income would be basically impossible, you would pay 19 - 5 = 14k/year, almost half of your income. Two children would be impossible. Remember how each family needs to have two children minimum to perpetuate life?
@cirosantilli/_file/prime-number-theorem by Ciro Santilli 35 Updated +Created
Consider this is a study in failed computational number theory.
The approximation converges really slowly, and we can't easy go far enough to see that the ration converges to 1 with only awk and primes:
sudo apt intsall bsdgames
cd prime-number-theorem
./main.py 100000000
Runs in 30 minutes tested on Ubuntu 22.10 and P51, producing:
Figure 1.
Linear vs approximation plot
. and are added to give a better sense of scale. is too close to 0 and not visible, and the approximation almost overlaps entirely with .
Figure 2.
. It is clear that the difference diverges, albeit very slowly.
Figure 3.
. We just don't have enough points to clearly see that it is converging to 1.0, the convergence truly is very slow. The logarithm integral approximation is much much better, but we can't calculate it in awk, sadface.
But looking at: en.wikipedia.org/wiki/File:Prime_number_theorem_ratio_convergence.svg we see that it takes way longer to get closer to 1, even at it is still not super close. Inspecting the code there we see:
(* Supplement with larger known PrimePi values that are too large for \
Mathematica to compute *)
LargePiPrime = {{10^13, 346065536839}, {10^14, 3204941750802}, {10^15,
     29844570422669}, {10^16, 279238341033925}, {10^17,
    2623557157654233}, {10^18, 24739954287740860}, {10^19,
    234057667276344607}, {10^20, 2220819602560918840}, {10^21,
    21127269486018731928}, {10^22, 201467286689315906290}, {10^23,
    1925320391606803968923}, {10^24, 18435599767349200867866}};
so OK, it is not something doable on a personal computer just like that.
Strategic nuclear weapon by Ciro Santilli 35 Updated +Created
ELF Hello World Tutorial / STT_FILE by Ciro Santilli 35 Updated +Created
Entry 1 has ELF64_R_TYPE == STT_FILE. ELF64_R_TYPE is continued inside of st_info.
  • 10 8: st_name = 01000000 = character 1 in the .strtab, which until the following \0 makes hello_world.asm
    This piece of information file may be used by the linker to decide on which segment sections go: e.g. in ld linker script we write:
    segment_name :
    {
        file(section)
    }
    to pick a section from a given file.
    Most of the time however, we will just dump all sections with a given name together with:
    segment_name :
    {
        *(section)
    }
  • 10 12: st_info = 04
    Bits 0-3 = ELF64_R_TYPE = Type = 4 = STT_FILE: the main purpose of this entry is to use st_name to indicate the name of the file which generated this object file.
    Bits 4-7 = ELF64_ST_BIND = Binding = 0 = STB_LOCAL. Required value for STT_FILE.
  • 10 13: st_shndx = Symbol Table Section header Index = f1ff = SHN_ABS. Required for STT_FILE.
  • 20 0: st_value = 8x 00: required for value for STT_FILE
  • 20 8: st_size = 8x 00: no allocated size
Now from the readelf, we interpret the others quickly.
2D rigid body dynamics simulator by Ciro Santilli 35 Updated +Created
Topological space by Ciro Santilli 35 Updated +Created

Pinned article: ourbigbook/introduction-to-the-ourbigbook-project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact