omazurov

They are not. There are orders of magnitude more rocket scientists than good profiler writers. And no, bottle rockets with flight recorders do not count.

Comment · 3 years ago

>...retrocausal models also open avenues of exploring a “time-symmetric” view of our universe, in which the laws of physics are the same regardless of whether time runs forward or backward.

... or sideways!

If you want a visual model that may help to build some intuition about that, I have one at [1]. Retrocausality is not explicitly spelled out in that model but "it's uh... uh... it's down there somewhere".

[1] https://github.com/OlegMazurov/Janus

Comment · 4 years ago

Necessity is the mother of invention? (Голь на выдумки хитра? :( )

Comment · 4 years ago

I can only repeat my initial statement:

> Multi-dimensional RS codes are an easy way to get to an absurdly huge size for real.

"Multi-dimensional" may mean 3,4,..,10 dimensions. "Absurdly huge" means a petabyte and beyond. "For real" means practical recovery of swaths of lost or damaged data. "Fountain LDPC codes" are essentially one-dimensional. Extending them to the ability of recovering an annihilated data center would make them impractical. Making them multi-dimensional would make them inferior to RS (which is still MDS in every single dimension).

Comment · 4 years ago

I'm not talking about CD-ROMs or immediate availability in any form. How would you encode a petabyte (for a starter) with LDPC/Turbo? Not available right away but accumulated over months with no predefined upper limit? Computational cost remains an important factor but other requirements take over.

Comment · 4 years ago

> Larger and larger block sizes are important. LDPC probably is the more practical methodology today, though I admit that I'm ignorant about them. Still cool to see someone try to push Reed Solomon to such an absurdly huge size though.

Multi-dimensional RS codes are an easy way to get to an absurdly huge size for real (granted they stop being MDS). Long term archiving is an obvious application. One-way communication, like in deep space, is another. Though, speed requirements are less demanding there. That one tried to push the envelope for a one-dimensional RS code to those limits is a curiosity. Some techniques may be useful in other practical approaches. It's a pity the code representation had to depart from GF(2^n).

Comment · 4 years ago

> But I’m here to tell you they got it wrong, and everyone’s been getting it wrong ever since. Students come away underwhelmed and baffled, and go on to become the next generation of teachers who repeat this process.

Yeah, this is how recursion works. "If it ain't broke, don't fix it" maybe?

Comment · 4 years ago

That's why there should be another parameter: you should split the key into N parts so that any M <= N can open the lock. You can increase M adding people you don't trust 100%, say to 8, but leave N at your comfortable level, 5. Even if those 3 conspire, they would still be 2 people short of being able to break the lock. You can do 12:5, give 5 parts to your spouse and spread the remaining 7 among your relatives and friends. There will still be a single point of failure, though, if somebody steals all 5 parts from him/her. You can decide to decrease allocation to only 4 parts so that your spouse would need to cooperate with any of the other trusted parties. The point is there is enough room for designing a scheme that is both secure and reliable.

Comment · 4 years ago

>> helped kindle the European Renaissance as we know it.

> The italian renaissance started in the 14th century for sure and maybe even in 13th century depending on who you ask. Though the exact date can be disputed, nobody disputes the fact that it started long before the fall of the byzantine empire in the mid 15th century.

The early "Renaissance" was Latin, the Renaissance proper was Greek. That's all you need to know to figure out when (1397+), where (Florence+), and how it started. The seed is more important than the soil.

Comment · 4 years ago

> Free will does not exist. It is logically inconsistent...

That line of argument makes no difference between the free will of humans and that of animals, insects, bacteria or rocks. But that can't possibly be true: we humans invented free will after all. That's the mental gymnastics that keeps me mentally strong. No beast, nor angel. "Freedom evolves" (DD).

Comment · 5 years ago

It's plain Java (i.e. JVM/JIT), ForkJoinTask based implementation. As in the original implementation, measurement is done around the quickSort() call.

One point is actually that the parallel quick sort algorithm is a bad benchmark for task schedulers (it doesn't scale well for one thing). Another point is, well, that one can spend two years of deep technical work and then be easily beaten by some "legacy" tech in the course of a morning exercise. Maybe those bearded guys were good for something after all :)

Comment · 5 years ago

Increasing the size of the array 10x (100_000_000) and filling a glaring omission:

Go (go1.17.1 darwin/amd64)

    took 5.591593544s
    took 5.285948722s
    took 5.218750076s
    took 5.239224787s
    took 5.131232207s

Zig (0.9.0-dev.959+f011f1393)

    took 3.48s
    took 3.37s
    took 3.44s
    took 3.43s
    took 3.49s

Java (openjdk version "17-ea")

    Time: 2684 ms
    Time: 2654 ms
    Time: 2840 ms
    Time: 2676 ms
    Time: 2649 ms

MacBook Pro Early 2013, 2.7 GHz Quad-Core Intel Core i7, 16 GB 1600 MHz DDR3