# nightcracker

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bio website location Leiden, Netherlands age 19 member for 3 years, 6 months seen Jun 6 at 6:31 profile views 52

Computer Science student and cryptography enthusiast.

You can contact me at orsonpeters@gmail.com.

# 59 Actions

 Jul2 awarded Curious Oct16 accepted Is this notation correct? Oct16 comment Is this notation correct? @TobiasKildetoft I'm afraid that will hurt the understanding. This is for describing a cryptographic scheme, and placing $\text{large_expression}$ and $x$/$y$ further apart from eachother (by introducing another variable or function) will make it harder to see that some events are mutually exclusive, on which the security of the scheme relies. Oct16 asked Is this notation correct? Oct6 comment FACE divided by D (base 16 arithmetic problem) What have you tried? Sep5 comment Why do you add +1 in counting test questions? I'd like to add that this is one of the reasons that in programming we almost exclusively work with up to exclusive bounds. Jul30 comment If a lottery has 300 tickets, shouldn't I win every 300 times I play @Nicolai: if a dice has 6 sides will it land on 1 every six rolls? Jul6 comment Counterexample of Beal Conjecture GCD=1 Prime Sum @DebraAxon A non-trivial car not lying on the critical line of the zeta function is not a counterexample to the Riemann hypothesis, because it talks about zeroes, not cars. Similarly, Beal's conjecture talks about $C^z$ with $z > 2$, not prime $C$ (which implies $z = 1$). Jun30 comment $x^4-3x^3-9x^2+2=0$, why does wolframalpha give complex solutions when they are real? @Arkamis: I'm pretty sure Wolfram Alpha uses an arbitrary precision library for its calculations, so the machine epsilon is irrelevant in that case. May6 comment Prove $a+b+c+d$ is composite Of course, pesky $1$ :D Nevermind. May6 comment Prove $a+b+c+d$ is composite This may be nitpicking, but $2 \cdot 3 = 3 \cdot 2$ does not imply $2 = xy$. Feb7 comment Fastest Square Root Algorithm @Hurkyl: I've been focusing on the former actually. But after benchmarking, I found this method to be slower - the overhead of the additions, squarings and multiplications is just not worth saving a division (on x64 with SSE, that is). Feb6 comment Fastest Square Root Algorithm @RustynYazdanpour: I'm 100% sure it's wrong, because it gives the wrong results (see my linked snippet). The correct formula for the square root is given here: mathpath.org/Algor/squareroot/algor.square.root.halley.htm Feb6 comment Fastest Square Root Algorithm Also, I think the formula you posted here is wrong: ideone.com/Reob0B Feb6 comment Fastest Square Root Algorithm Guys, I have a feeling this answer has the potential to be actually faster than Newton's Method. The reason is because per iteration you still use only one division operation (which is about 14 times as slow as addition/multiplication on x86) while having cubic convergence. Feb6 comment Fastest Square Root Algorithm @FrankScience: well you'd hardcode Pi of course. The gamma function is the largest hurdle here, I think. Dec22 comment Can you explain this card trick? Link rot within one day. Classic. Dec7 awarded Autobiographer Sep8 comment What mathematical ideas/concepts became obsolete due to technological progress? "Most, if not all, present-day computers use a different algorithm to calculate square roots." Yes, but it's not the algorithm you linked, because that's a (rather inaccurate) approximation. Most present-day FPU's have a sqrt instruction (for example SSE's sqrtss), which is most likely (depending on processor vendor) a digit-by-digit algorithm hardcoded in circuitry, plus some IEEE exception handling. Apr24 awarded Citizen Patrol