Sat Jun 14 04:10:34 PM +08 2025#59
N.Wirth. Algorithms and Data Structures. Oberon version
Harold Abelson, Gerald Jay Sussman, Julie Sussman. Structure and Interpretation of Computer Programs
Fri Jun 13 12:45:16 PM +08 2025#58
ken-and-den.jpeg
Thu Jun 12 09:10:05 PM +08 2025#57
«Мы постоянно меняемся и очень важно помнить о том, что ты был положительным персонажем»
Бараш
Thu Jun 12 08:44:35 PM +08 2025#56
Thu Jun 12 03:14:50 AM +08 2025#55
First, we want to establish the idea that a computer language is not just a way of getting a computer to perform operations but rather that it is a novel formal medium for expressing ideas about methodology. Thus, programs must be written for people to read, and only incidentally for machines to execute. Second, we believe that the essential material to be addressed by a subject at this level is not the syntax of particular programming-language constructs, nor clever algorithms for computing particular functions efficiently, nor even the mathematical analysis of algorithms and the foundations of computing, but rather the techniques used to control the intellectual complexity of large software systems.
Wed Jun 11 07:00:24 PM +08 2025#54
Start ridiculously small (a single pushup or one minute of meditation)
Attach new behaviors to existing routines (meditate after brushing teeth)
Celebrate immediate small wins to reinforce the behavior
Focus on consistency rather than perfection
Design your environment to make good habits easier and bad habits harder
Wed Jun 11 06:59:03 PM +08 2025#53
Cultivating positive habits provides a powerful mechanism for life improvement. Regular exercise represents a classic example—initially challenging to establish but relatively easy to maintain once integrated into your routine. This principle applies equally to reading, writing, meditation, or other beneficial practices. With exercise specifically, I personally reject the concept of scheduled rest days because they tend to multiply into extended inactivity periods. Instead, I find daily movement more sustainable, even if it’s minimal, adjusting intensity according to energy levels and recovery needs.
Tue Jun 10 04:02:39 PM +08 2025#52
Tue Jun 10 11:02:15 AM +08 2025#51
This book is dedicated, in respect and admiration, to the spirit that lives in the computer.
``I think that it's extraordinarily important that we in computer science keep fun in computing. When it started out, it was an awful lot of fun. Of course, the paying customers got shafted every now and then, and after a while we began to take their complaints seriously. We began to feel as if we really were responsible for the successful, error-free perfect use of these machines. I don't think we are. I think we're responsible for stretching them, setting them off in new directions, and keeping fun in the house. I hope the field of computer science never loses its sense of fun. Above all, I hope we don't become missionaries. Don't feel as if you're Bible salesmen. The world has too many of those already. What you know about computing other people will learn. Don't feel as if the key to successful computing is only in your hands. What's in your hands, I think and hope, is intelligence: the ability to see the machine as more than when you were first led up to it, that you can make it more.''
Alan J. Perlis (April 1, 1922-February 7, 1990)
Tue Jun 10 12:05:09 AM +08 2025#50
Wega
Mon Jun 09 06:33:03 PM +08 2025#49
IBM System/360
Mon Jun 09 12:39:01 PM +08 2025#48
Embrace object-oriented patterns for organization. For organizing larger parts of your application, consider object-oriented constructs. Using structs or enums can encapsulate related data and functions, providing a clear structure without worrying about the details.
Leverage functional patterns for data transformations. Especially within smaller scopes like functions and closures, functional methods such as mapping, filtering, or reducing can make your code both concise and clear. Use functional programming when you can phrase your problem as a series of transformations over some data.}
Use imperative style for granular control. In scenarios where you’re working close to the hardware, or when you need explicit step-by-step execution, the imperative style is often a necessity. It allows for precise control over operations, especially with mutable data. This style can be particularly useful in performance-critical sections or when interfacing with external systems where exact sequencing matters. However, always weigh its performance gains against potential readability trade-offs. If possible, encapsulate imperative code within a limited scope.
Prioritize readability and maintainability. Regardless of your chosen paradigm, always write code that’s straightforward and easy to maintain. It benefits not only your future self, but also your colleagues who might work on the same codebase.
Avoid premature optimization. Don’t prematurely optimize for performance at the cost of readability. The real bottleneck might be elsewhere. Measure first, then optimize. Elegant solutions can be turned into fast ones, but the reverse is not always true.
Mon Jun 09 09:40:54 AM +08 2025#47
Mon Jun 09 12:18:11 AM +08 2025#46
«Как правило, одиночество вокруг нас — это плод нашего воображения, а на самом деле жизнь вокруг нас бьет ключом, в ожидании когда мы вольемся в её шумный поток»
КарКарыч
Sun Jun 08 12:17:45 PM +08 2025#45
108. Проектируйте структуры данных в последнюю очередь.
Добавление полей данных выполняется в процессе проектирования в последнюю очередь. Другими словами, после того, как вы разработали сообщения, вам нужно понять, как реализовать возможности, запрашиваемые этими сообщениями. Вероятно, это труднейшая часть процесса объектно-ориентированного проектирования для структурного программиста: заставить себя не думать о лежащей в основе структуре данных до тех пор, пока не будет готовы полностью система обмена сообщениями и иерархия классов.
В этот момент процесса проектирования вы также добавляете закрытые (private) "рабочие" (или "вспомогательные") функции, которые помогают обработчикам сообщений справиться со своей работой.
Sat Jun 07 09:03:56 AM +08 2025#44
Still, the history of mainstream programming languages is essentially a story of programmers vocally and emphatically rejecting what eventually proved to be some of the most incredibly successful innovations in the history of the field. Assembly programmers largely laughed at FORTRAN, but just a few decades later, there were nevertheless very few remaining assembly programmers. First-class functions were widely derided as needlessly complicated and confusing until programmers were forced to finally take the time to learn to use them once JavaScript became a load-bearing language by historical accident, and within a decade, they became a required feature for every major programming system. Sophisticated type systems largely retain a perception of overengineered, ivory-tower elitism, but many of the programmers who hold those very opinions have enthusiastically adopted Rust, a language that features a type system so complex that idiomatic Rust code can easily put Haskell programs to shame.
Thu Jun 05 12:55:14 PM +08 2025#43
The essential, most stubborn problems in programming languages come from unavoidable tensions between conflicting desires and requirements. We want loosely coupled software components that can be easily reused, but we also want the performance benefits of tight coupling and specialization. We want flexible programming languages that do not impose upon our freedom of expression, but we also want the benefits of static program analysis and powerful safety guarantees. We want sophisticated type systems that allow specifying ever more complex invariants, but we also want readable type signatures that won’t regularly end up longer than the code itself.
Tue Jun 03 02:33:22 PM +08 2025#42
https://en.wikipedia.org/wiki/Sales_(band)
Tue Jun 03 12:48:26 PM +08 2025#41
Functional programming allows a programmer to express ideas in an inherently mathematical way. This makes FP great for things like mathematical proofs, or great for people with a mathematical background who struggle to think like a programmer. It also simplifies code - if I'm reading a function with zero side-effects, or zero mutation of some data structure, then I can very clearly see the input, transformation and output. This style of function should be prioritised where appropriate, even in a procedural language like C. Reducing cognitive load for a programmer is clearly a bonus.
Tue Jun 03 11:57:53 AM +08 2025#40
The difference may not seem drastic, but the compounding performance returns will be vital in applications like simulations, games, and real-time systems where each CPU cycle is gold-dust, and each cache miss a deterrent to having a great product. So, in a well-written program, an engineer may make use of SoA for field-wise operations, and AoS for entity-wise operations.
Mon Jun 02 10:30:25 AM +08 2025#39
Feeling stronger
Fri May 30 03:14:46 PM +08 2025#38
$ python benchpop.py
Size: 1000 - With: 0.0015s, 10318 comps | Without: 0.0018s, 16850 comps
Size: 2000 - With: 0.0048s, 22672 comps | Without: 0.0042s, 37745 comps
Size: 5000 - With: 0.0110s, 63319 comps | Without: 0.0120s, 107652 comps
Size: 10000 - With: 0.0206s, 136634 comps | Without: 0.0276s, 235294 comps
Size: 20000 - With: 0.0454s, 293288 comps | Without: 0.0583s, 510657 comps
Oh, there it is. 🙄
Fri May 30 03:07:39 PM +08 2025#37
$ python bench.py
With siftdown inlined: 3.995546 seconds, Comparisons: 1648612
Without siftdown: 3.329431 seconds, Comparisons: 1882563
🫣
Fri May 30 03:02:48 PM +08 2025#36
$ python bench.py
With _siftdown: 6.305621 seconds, Comparisons: 1649692
Without _siftdown: 5.422437 seconds, Comparisons: 1880839
🤔
Thu May 29 09:48:32 PM +08 2025#35
I am confused. 🧠
Thu May 29 09:46:42 PM +08 2025#34
Ok, chat. Write a python script that must benchmark some code.We will benchmark two slightly different implementations of the heap data structure. In Python. As reference we will take heapq.py module of the Python standart library which contains this code
def _siftup(heap, pos):
endpos = len(heap)
startpos = pos
newitem = heap[pos]
# Bubble up the smaller child until hitting a leaf.
childpos = 2*pos + 1 # leftmost child position
while childpos < endpos:
# Set childpos to index of smaller child.
rightpos = childpos + 1
if rightpos < endpos and not heap[childpos] < heap[rightpos]:
childpos = rightpos
# Move the smaller child up.
heap[pos] = heap[childpos]
pos = childpos
childpos = 2*pos + 1
# The leaf at pos is empty now. Put newitem there, and bubble it up
# to its final resting place (by sifting its parents down).
heap[pos] = newitem
_siftdown(heap, startpos, pos)
There is possible another implemetations of siftup routine, withou calling _siftdown function. We need just on each iteration compare if value at pos index is bigger than children. If not we must break the loop, stop iteration.
Create two functions to heapify list, one using siftup which breaks the loop, another one using snippet I gave. Timeit and benchmark the best way possible agains both implementations, format the out put. give me the script
https://github.com/fuzz88/rust_stuff/blob/master/heap/bench.py
fuzz@workstation:~/code/rust_stuff/heap$ python bench.py
Heapify Performance Comparison (10 runs on list of 10,000 items):
With _siftdown: 0.030211 seconds
Without _siftdown: 0.011579 seconds
Result: Alternative implementation without _siftdown is faster.
🫠
Thu May 29 09:35:05 PM +08 2025#33
Yeah. I guess swapping two elements of slice is just faster than assigning one to another through = and pointing this values by index. No matter how many compare operations we can avoid.
Thu May 29 09:19:10 PM +08 2025#32
Ok, here is the trick in Python's heap structure implementation that allows us to cut amount of comparison when sifting up items in the heap.
https://github.com/python/cpython/blob/3.13/Lib/heapq.py#L278
We don't compare parent value with the children when sifting it up, assuming that item which is taken from the leaf will end up somewhere near the leaf. The idea (D.Knuth, Art of Programming, Volume 3) is to sift item through smallest of the children (and shifting smallest child towards the root on each step) to the leaf without swapping it in a process, then assign it to the leaf, and then sift it down to the proper place. Doing it this way must reduce amount of "compare" operations, because sifting item down to it place from the leaf is shorter path than the sifting it up to its location towards the leaf. It is low price to don't stop ("break" the loop) on proper location, but go down to the leaf with low cost operations and then go a little bit up comparing values. I know I have formulated this idea twice already. :-) Here is the third time: we make long path cheaper, according the heuristics about nature of the value we are sifting through the heap.
Now, here is my research.
I had wrote a little bit of code in Rust, playing with the heap. I am 37 years old programmer, but never played with the heap data structure. Oh, boy, brothers. Just having some fun here.
And I've tested and benchmarked some code. And... idk, but my benchmarks in Rust said that "non-optimized" version when we swapping items towards the leaf and breaking the loop when we arrived is faster. Is this compiler optimizations? Some low-level stuff? I am not really into that. Maybe I made a mistake.
https://github.com/fuzz88/rust_stuff/blob/master/heap/src/main.rs#L73
test tests::bench_heapify_not_optimized ... bench: 2,796.01 ns/iter (+/- 54.45)
test tests::bench_heapify_optimized ... bench: 6,668.45 ns/iter (+/- 182.72)
Just a memo to myself: benchmark critical parts, make decisions based on the data. Or just use "good enough" stuff for the task.
I will call it a day.
Wed May 28 05:32:22 PM +08 2025#31
"Be patient. Your future will come to you and lie down at your feet like a dog who knows and likes you no matter what you are."
Wed May 28 01:58:00 PM +08 2025#30
...And Justice for All (1979)
Wed May 28 11:04:36 AM +08 2025#29
What is good style?
Good style in any language consists of code that is:
Understandable
Reusable
Extensible
Efficient
Easy to develop and debug
It also helps ensure correctness, robustness, and compatibility.
Maxims of good style are:
Be explicit
Be specific
Be concise
Be consistent
Be helpful (anticipate the reader's needs)
Be conventional (don't be obscure)
Build abstractions at a usable level
Allow tools to interact (referential transparency)
Know the context when reading code:
Who wrote it and when?
What were the business needs?
What other factors contributed to the design decisions?
Mon May 26 11:46:21 PM +08 2025#28
Sat May 17 10:40:56 PM +08 2025#27
Thu May 15 08:34:58 PM +08 2025#26
Wed May 14 05:26:51 PM +08 2025#25
Thu May 08 01:56:23 PM +08 2025#24
vo2max
Sun May 04 08:58:09 AM +08 2025#23
Sun May 04 08:25:24 AM +08 2025#22
Wed Apr 30 12:40:53 PM +08 2025#21
well tapered
Tue Apr 29 12:31:46 PM +08 2025#20
When you ignore convention, you must be ready to stand your ground.
Sat Apr 26 12:55:49 AM +08 2025#19
¯\_(ツ)_/¯
Mon Apr 21 10:56:38 PM +08 2025#18
In computer programming our basic building block has an associated time grain of less than a microsecond, but our program may take hours of computation time. I do not know of any other technology covering a ratio of 10¹⁰ or more: the computer, by virtue of its fantastic speed, seems to be the first to provide us with an environment where highly hierarchical artefacts are both possible and necessary. This challenge, viz. the confrontation with the programming task, is so unique that this novel experience can teach us a lot about ourselves. It should deepen our understanding of the processes of design and creation, it should give us better control over the task of organizing our thoughts.
Tue Apr 15 08:45:24 AM +08 2025#17
Как вы видите даже одна операция выделения памяти может стать узким местом, если она выполняется внутри часто вызываемой логики. В играх динамическое выделение памяти в большинстве случаев запрещено, вам 95% завернут такой код на ревью. Без веских на такое действие причин выделять память где хочется нельзя. Все, что может быть выделено, должно быть выделено до старта уровня.
Mon Apr 14 02:11:45 PM +08 2025#16
Verba/Salix acutifolia
Fri Apr 11 01:56:10 PM +08 2025#15
Run/walk
Thu Apr 10 01:13:27 PM +08 2025#14
2016 on one's own
Tue Apr 08 04:58:03 PM +08 2025#13
Tue Apr 01 08:52:06 PM +08 2025#12
Первая весенняя свежесть, +12
Sun Mar 30 01:48:58 PM +08 2025#11
1936
Sun Mar 30 10:25:56 AM +08 2025#10
There you have it: some of the weirdest things in the Linux kernel's git history. There are 1,549 octopus merges, one of which has 66 parents. The most heavily diverged merge has 22,445,760 lines of diff, though it's a bit of a technicality because it shares no history with the rest of the repo. The kernel has four separate "initial" commits, one of which was a mistake. None of this will show up in the vast majority of git repos, but all of it is well within git's design parameters.
Sat Mar 29 08:29:22 PM +08 2025#9
Above all, you do not let your tests drive your design, you let your design drive your tests! The design is going to point you in the right direction of what layer in the MVC cake should get the most test frosting.
When you stop driving your design first, and primarily, through your tests, your eyes will open to much more interesting perspectives on the code. The answer to how can I make it better, is how can I make it clearer, not how can I test it faster or more isolated.
The design integrity of your system is far more important than being able to test it any particular layer. Stop obsessing about unit tests, embrace backfilling of tests when you're happy with the design, and strive for overall system clarity as your principle pursuit.
Tue Mar 25 11:11:44 AM +08 2025#8
Unfortunately, SawStart is one-use-only. Once started, the blade cannot be stopped, and must be replaced with a fresh blade while the running one is carefully disposed of.
Mon Mar 24 03:37:21 PM +08 2025#7
Long Aerobic
Sun Mar 23 11:23:49 PM +08 2025#6
Про это пишет Хэмингуэй в «Празднике, который всегда с тобой»:
«Радостно было спускаться по длинным маршам лестницы, сознавая, что ты хорошо поработал. Я всегда работал до тех пор, пока мне не удавалось чего-то добиться, и всегда останавливал работу, уже зная, что должно произойти дальше. Это давало мне разгон на завтра».
Wed Mar 19 02:10:23 PM +08 2025#5
Vibing
Mon Mar 17 03:36:38 PM +08 2025#4
Лайков не будет)
Mon Mar 17 02:35:29 PM +08 2025#3
Хочется, конечно, чтобы здесь было всегда красиво. Но будет, как будет. 😂
И нужно проверить несколько гипотез.
https://natureofcode.com/
Mon Mar 17 02:29:39 PM +08 2025#2
Космос наш ждёт
Mon Mar 17 02:16:08 PM +08 2025#1
Пифагорейское