Tweetovi

Blokirali ste korisnika/cu @shachaf

Jeste li sigurni da želite vidjeti te tweetove? Time nećete deblokirati korisnika/cu @shachaf

  1. 10. sij

    When you (in Facebook's words) "Set up a modern web app by running one command", this is what happens:

    Poništi
  2. proslijedio/la je Tweet
    3. sij

    A really nice proof of Pythagoras’s theorem and the cosine rule.

    Poništi
  3. 29. pro 2019.

    OK, I think it's just clause deletion. I misread MiniSat's output as indicating that it wasn't deleting that many clauses, so I thought there was something else going on, but in fact it deletes over 98% of the clause database over its run on this instance.

    Prikaži ovu nit
    Poništi
  4. 29. pro 2019.

    Anyone into SAT solvers? I wrote a simple version of FirstUIP CDCL but -- despite reducing decisions and units a lot -- it made my solver much slower (even with 2-watched-literals). Is it just that I'm not deleting clauses yet? How can I tell whether my learnt clauses are bad?

    Prikaži ovu nit
    Poništi
  5. 29. pro 2019.

    Talk about falsifiability has always seemed kind of funny to me. The negation of a falsifiable statement ("all swans are white") is a verifiable statement ("there exists a nonwhite swan"). Both are perfectly reasonable!

    Poništi
  6. 26. pro 2019.

    People talk about "optional" garbage collection, where you can choose whether to use GC or not. But standard GC is a global property of your program -- if a library uses GC, you're forced to too. The only viable actually optional GC would have to be local. Does anyone do that?

    Poništi
  7. proslijedio/la je Tweet
    22. ruj 2019.

    This insanely cool dynamic history of infectious diseases before/after vaccines. Makes you want to stand up and cheer every time a disease bar goes green and slams down 👨🏻‍🔬👩🏽‍🔬 Another big h/t to u/rarohde

    Prikaži ovu nit
    Poništi
  8. 18. pro 2019.

    What's a good library for ordered key-value maps? I wrote a pretty naive in-memory B+ tree in C, and it's a fair bit faster than Rust's BTreeMap<u64, u64> and absl::btree_map<uint64_t, uint64_t> at most workloads. Is there another library I should benchmark against?

    Poništi
  9. proslijedio/la je Tweet
    3. pro 2019.

    You have a pack of 52 playing cards. • Shuffle the cards. • Pick a card at random. • Note what it is. • Return it to the deck. • If you’ve now seen every card, you’re done. • Otherwise, repeat. What is the expected number of cards picked, rounded to the nearest integer?

    Prikaži ovu nit
    Poništi
  10. 2. pro 2019.

    "left inverse" is such a bad term -- I always have to triple-check which way is which. But "pre-inverse" seems almost as confusing. I've been trying to use "section"/"retraction", but is there a better alternative?

    Poništi
  11. proslijedio/la je Tweet
    28. stu 2019.

    A full rebuild of a ten-million line program should take less than a second on a modern many-core x64 processor.

    Prikaži ovu nit
    Poništi
  12. proslijedio/la je Tweet
    23. lis 2019.

    Literally. As in, the truth table for a^b is A^B = 0xaa ^ 0xcc = 0x66. The truth table for "~a & c" is ~A & C = 0x44. The truth table for "a | b | c" is A|B|C = 0xfe. And so forth.

    Prikaži ovu nit
    Poništi
  13. proslijedio/la je Tweet
    24. lis 2019.

    oh you're a daoist? name the dao

    Prikaži ovu nit
    Poništi
  14. proslijedio/la je Tweet
    25. lis 2019.
    Poništi
  15. 17. lis 2019.

    This seems to work well in practice, even under weaker conditions: Many SAT solvers use this schedule (called "Luby restarts") even though they keep state between runs, rather than being truly independent.

    Prikaži ovu nit
    Poništi
  16. 17. lis 2019.

    Even assuming a "worst case" -- every run of size <2^k is wasted, and effectively so is any time past 2^k -- you get enough trials of the right size to be within a constant factor of (2^k,2^k,2^k,...).

    Prikaži ovu nit
    Poništi
  17. 17. lis 2019.

    The optimal schedule looks like this: (1,1,2,1,1,2,4,1,1,2,1,1,2,4,8,1,...). At the time that you finish your first run of size 2^n, you've spent as much total time on runs of each size, 1,2,...2^n.

    Prikaži ovu nit
    Poništi
  18. 17. lis 2019.

    But what if you don't know the distribution? It turns out you can get within a constant factor of the optimal restart schedule! This is described in _Optimal Speedup of Las Vegas Algorithms_ by Luby, Sinclair, Zuckerman (<>).

    Prikaži ovu nit
    Poništi
  19. 17. lis 2019.

    If you know the distribution, you can figure out an optimal restart point t such that it makes sense to restart after t steps. Since runs are independent, you'll want to repeatedly wait t steps before restarting.

    Prikaži ovu nit
    Poništi
  20. 17. lis 2019.

    Luby restarts: A Las Vegas algorithm is an algorithm which is guaranteed to succeed, but whose runtime is random. If you start a run, and wait for some time, at what point should you restart and hope to save time?

    Prikaži ovu nit
    Poništi

Čini se da učitavanje traje već neko vrijeme.

Twitter je možda preopterećen ili ima kratkotrajnih poteškoća u radu. Pokušajte ponovno ili potražite dodatne informacije u odjeljku Status Twittera.

    Možda bi vam se svidjelo i ovo:

    ·