Right, that's enough computers everyone. Back to books.
The Emperor Protects!
2*7*24*60 = 047300 # two weeks, in minutes
This is not a coincidence. Ignoring the trailing zeros, we have: 5*7*011 = 5*077 = 5*0100 - 5 = 0473
https://www.ietf.org/rfc/rfc9759.html
OP apparently noticed that two weeks is almost 20480 decimal = 050000 octal minutes, just 320 = 0500 minutes in fact.
[1] https://www.researchgate.net/publication/390635826_Structura...
> ccdoom is a freestanding C implementation, as distinct from hosted implementations. The difference is that freestanding implementations need not support the full standard library, and may specify an alternative name and signature for main [2, Section 5.1.2.2].
> int math_errhandling(int argc, char* argv[]);
> Since math_errhandling is the program entry point and therefore always implicitly used, any program that fails to define it then contains a use of an undefined identifier, which is undefined behaviour [2, Section 6.9.1p5].
> On the other hand, any program which does define math_errhandling also has undefined behaviour. Per the standard [2, Section 7.12p20]:
> Falling with Style: Factoring up to 255 “with” a Quantum Computer
is brilliant in a straightforward way, and I also learned something about Shor's algorithm. The first paragraph of intro and the abstract say:
> Historically, most papers that claimed they “ran Shor’s algorithm” didn’t run Shor’s algorithm. It’s unfortunately common to run circuits inspired by Shor’s algorithm, but with key pieces replaced by trivial pieces.
> In this paper, I explain how I factored all numbers up to 255 using Shor’s algorithm on a real quantum computer. I performed exactly the classical preprocessing specified by Shor’s algorithm, exactly the quantum circuit requested by Shor’s algorithm, and exactly the post-processing specified by Shor’s algorithm.
and this is true! He used IBM's quantum service (https://quantum.ibm.com/services/resources?tab=systems) with:
> my circuit for factoring 15 weighs in at 44405 two-qubit gates. And my circuit for factoring 253 weighs in at 245750 two-qubit gates. Amazingly, despite the fact that they vastly exceed the allowed size, the system accepted these ridiculous circuits.
What's the catch? Well, it's that:
> I’ll quickly review the classical and quantum steps of Shor’s algorithm. Before talking to a quantum computer, Shor’s algorithm performs some classical preprocessing. First, it checks if n (the number to factor) is even, because even numbers would cause trouble later. If so, it succeeds by returning the factor 2. Second, it checks if n is prime. Prime numbers can’t be factored, so in this case the method returns an error saying no factor exists. Third, the algorithm picks a random number g between 2 and n − 2, and computes the greatest common divisor (gcd) of g and n. If gcd(g, n) ≠ 1, then it happens to be a factor of n and so is returned as the result. Fourth, it’s finally time to actually use the quantum computer (whether it be real, simulated, or replaced by a random number generator). This is the expensive step, and the step that I’m counting in order to compare the different samplers. A quantum circuit based on g and n is generated, and executed, producing a sample m. Fifth, Shor’s algorithm classically computes the fraction that’s closest to m/4^{⌈log_2(n)⌉}, limiting the fraction’s denominator d to be at most n. Sixth, a candidate factor is generated by computing gcd(n, 1 + g^{⌊d/2⌋} mod n). If the candidate is actually a factor of n, it’s returned as the answer. Otherwise the algorithm restarts.
because of which:
> In other words, for small numbers, Shor’s algorithm succeeds quickly regardless of how well your quantum computer works.
It also cites a serious 2013 paper in Nature that made the same point: Oversimplifying quantum factoring, DOI 10.1038/nature12290.
djoldman•14h ago
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https://www.youtube.com/@tom7
https://www.youtube.com/watch?v=Ae9EKCyI1xU