ex0: theory document

.gitignore

@@ -54,3 +54,4 @@ dkms.conf
 
 *.zip
 *.pdf
+*.png

exercise0/Makefile

@@ -8,3 +8,6 @@ run:
 show:
 	make run
 	feh after.bmp
+
+convert:
+	magick after.bmp after.png # for showing image in pdf

exercise0/main.typ

@@ -0,0 +1,126 @@
+#import "@preview/cetz:0.3.2";
+#import "@preview/cetz-plot:0.1.1": plot
+#import "@preview/physica:0.9.4": *
+#import "@preview/plotsy-3d:0.1.0": plot-3d-parametric-surface
+#import "@preview/fletcher:0.5.4" as fletcher: diagram, edge, node
+
+#set page(paper: "a4", margin: (x: 2.6cm, y: 2.8cm), numbering: "1 : 1")
+#set par(justify: true, leading: 0.52em)
+
+#let FONT_SIZE = 18pt;
+#set text(font: "FreeSerif", size: FONT_SIZE, lang: "us")
+#show math.equation: set text(font: "Euler Math", size: (FONT_SIZE * 1.0), lang: "en")
+
+#set heading(numbering: none)
+#show heading.where(level: 1): it => {
+  rect(inset: FONT_SIZE / 2)[#it]
+}
+
+// Dracula palette
+#let bg = rgb("#282a36")
+#let fg = rgb("#f8f8f2")
+#let sec = rgb("#44475a")
+
+// Inline (aligned to surrounding text)
+#show raw.where(block: false): it => box(
+  fill: sec,
+  inset: (x: 5pt, y: 3pt, top: 3pt), // extra top inset
+  baseline: 2.75pt, // lowers box
+  radius: 2.5pt,
+  text(fill: fg, size: 0.88em, it),
+)
+
+// Block (unchanged)
+#show raw.where(block: true): it => block(
+  fill: bg,
+  inset: 10pt,
+  radius: 4pt,
+  text(fill: fg, font: "Fira Code", it),
+)
+
+
+#align(center)[
+  #text(size: FONT_SIZE * 2, weight: "bold")[#underline[exercise 0]]
+]
+
+these are my solutions to the first (optional) exercise set of TDT4200.
+
+i recommend using a PDF-reader like
+#link("https://wiki.archlinux.org/title/Zathura")[#text(blue.darken(5%))[zathura]],
+for no particular reason other than that it is cool.
+
+this document was created using
+#link("https://typst.app/")[#text(blue.darken(5%))[typst]].
+
+#v(42pt)
+
+#outline(title: none)
+
+#v(42pt)
+
+
+= how to run my code
+
+the project utilizes
+#link("https://nixos.org/")[#text(blue.darken(5%))[nix]]
+to manage dependencies.
+
+with it (and with
+#link("https://wiki.nixos.org/wiki/Flakes")[#text(blue.darken(5%))[flakes]]
+enabled), you can simply run `nix develop` to enter a development shell with the
+necessary dependencies, as specified in `flake.nix` and `flake.lock`. in this
+shell you can build the bmp-image using `make run` or to see it immediately,
+using
+#link("https://wiki.archlinux.org/title/Feh")[#text(blue.darken(5%))[feh]],
+you can run `make show`.
+
+#v(100%)
+
+= theory
+
+== 1) what is the purpose of a Makefile?
+
+a Makefile is like a shell-script that performs some pre-defined tasks. it is
+particularly useful as a *build tool* for complex compilation pipelines in
+development environments relying on such compiled languages like C.
+
+`make show` is an example of a neat short-hand to compile and run my program,
+but also finally displaying the image result to me using the lightweight CLI
+feh.
+
+== 2) what is a pointer in C?
+
+a *pointer* in C is a memory address equipped with a primitive type, determining
+the semantics of *pointer arithmetic*, i.e. when you increment the pointer. for
+example, if you increment a pointer with a type of size 8 bytes, it will jump to
+the memory address 8 bytes forward. a *void pointer* is a true wildcard pointer,
+having 'no type', thus being able to point to any memory, disregarding
+alignment.
+
+== 3) what does the compile flag `-O3` do?
+
+GCC, like most compilers, have lots of flags that alter their behavior. given
+the age of C and the amount of clever people in the world that have dedicated
+time to crafting a perfect compiler, GCC is capable of analyzing the
+code to perform optimizations. `gcc -O3 source.c` means to compile a source file
+with *aggressive optimizations*. examples of this could be unrolling loops,
+recognizing patterns or using more specialized (and faster) instructions (if
+available).
+
+note that there have been examples of compiler optimizations introducing weird
+bugs (i think), due to slight alterings of internal semantics.
+
+== 4) how do you pass a value by reference?
+
+passing a value by reference is the preferred way of handling data transfer in
+C, as opposed to other languages, where data may be passed to a function as
+a *pure copy*. copying memory is expensive, both time-wise and space-wise. it
+scales linearly, so thus if you have millions of data points, and you wish to
+pass it around lots, copying it each time could be considered unoptimal. that's
+why you wish to refer to your data using pointers, also known as *references*.
+
+= じゃああ、またね。
+
+#align(center)[
+  #image("after.png", width: 80%)
+]