The discussion revolves around a proposed 4-dimensional integral for calculating Pi(x), exploring its potential advantages over existing methods. Participants engage in technical reasoning, questioning the validity and efficiency of the proposed method, and comparing it to other approaches in number theory.
Discussion Character
Debate/contested
Technical explanation
Mathematical reasoning
Main Points Raised
One participant presents a formula for Pi(x) using a 4-dimensional integral, claiming it to be the best method.
Another participant questions the definition of "best," asking for clarification on whether it refers to speed or accuracy and challenges the claim of it being the fastest method.
Some participants suggest using Monte Carlo methods to compute the integral, asserting that the number of operations remains constant regardless of the variable t.
Others argue that the variable nature of t implies that the number of operations may not be constant and could require more computations for larger values.
Concerns are raised about the accuracy and runtime needed for calculating Pi(10^100) using the proposed method.
One participant expresses frustration over the lack of recognition for their method, claiming it is novel in its integral approach compared to traditional summation methods.
Another participant counters that integral expressions for Pi(x) are not new and references existing literature that may provide simpler and more efficient methods.
There is a discussion about the implications of algorithm complexity and the feasibility of achieving constant runtime for calculating Pi(x). Some participants challenge the assumptions made about the operations required.
Areas of Agreement / Disagreement
Participants express a range of views, with no consensus on the validity or superiority of the proposed method. Disagreements arise regarding the efficiency, novelty, and computational complexity of the integral approach compared to existing methods.
Contextual Notes
Participants highlight limitations in the proposed method, including assumptions about the number of operations and the complexity of calculating Pi(x) as x increases. There are references to existing literature that may challenge the novelty of the approach.
sorry matt perhpas i exagerated a bit..i thought it was the best because (at least i thought) it provided Pi(x) without calculating a sum or without knowing all the primes but i don,t know how to calculate the time involved running it.
i have given an integral for Pi(e^1/t) so if we want to know the value of Pi for high values we need to calculate the integral for small t
you needn,t make me fun of my poor engilsih or my scarce knowledge of numerical methods, in fact i am a physicist (surprised?) by i like math and someday i would like to contribute to math and physics...
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#33
keebs
19
0
i have given an integral for Pi(e^1/t) so if we want to know the value of Pi for high values we need to calculate the integral for small t
t may be small, but e1/t is large.
you needn,t make me fun of my poor engilsih or my scarce knowledge of numerical methods, in fact i am a physicist (surprised?) by i like math and someday i would like to contribute to math and physics...
What do you do in physics then? Where do you work?
I know you're a physics student, you have said so before. No one is making fun of your poor English, though I have in the past explained to you that the "papers" you have written are poorly presented and thus that will count against you attempting to submit them to anyone. Nor is anyone making fun of the fact that you know no numerical methods. we are pointing out that your claims of speed simplicity uniqueness and originality are unfounded and that making grand claims such as "this probably deserves a field's medal but you're too snobbish to accept that someone not famous could have come up with it" are not winning you any supporters. attacking those who point out the mathematical flaws with such non-mathematical attacks also only serves to underline that you are not prepared to listen and that you probably cannot defend oyur idea on mathematical grounds. you have been given a lot of attention on this forum for your ideas.
A run-time analysis is probably best demonstrated by a (simple) example:
Your algorithm is to check if the number n is prime by trial dividing n by every number up through √n.
In pseudocode, it looks like:
Code:
for m in the range 2, 3, 4, ..., [√n]
r := the remainder of n / m
if r == 0
print "n is composite"
quit
end for
print "n is prime"
In the worst-case, we have to go through this loop [√n] - 1 times. Each time through the loop, we must compute one remainder. So, we say that, in the worst-case, this algorithm tests for primality using O(√n) remainder operations. (We can say exactly how many, but that level of detail is generally not of theoretical importance)
(We must also increment m, test if we're done looping, test if the remainder is zero, and other minor things, but these are considered insignificant compared to the rest of the work being done)
Now, if we assume a remainder operation consumes one "unit" of time, we would say that this algorithm runs in O(√n) time, or in "square-root time". For example, that would mean if we quadruple the size of the input, the running time is only doubled.
However, that assumption is not really valid.
I don't recall precisely how much time it takes to compute the remainder of a / b, so I'll make an underestimate, and say it takes O(log a) time to compute the remainder of a / b. (Because it takes at least log a time to simply read all the digits of a)
So, this primality testing algorithm really runs in O(√n log n) time.
Compare this to, say, the AKS primality test, which is said to run in O((log n)^{4 + \epsilon}) time. (ε, here, is your favorite small positive number. Basically, it's saying that using the exponent 4 is an underestimate, but using anything bigger than 4 is an overestimate)
By calculus, we know that √n log n grows much faster than (log n)^(4 + ε), so we say that the latter algorithm is asymptotically faster than the former.
In practice, that means when n is sufficiently large, the AKS primality test will generally take (much) less time than trial division.
#36
eljose
484
0
let,s suppose we know a method to calculate pi(e^t) by means of a double complex integral..then we will need a time O(t^a) a>0 so to know the value of pi(u) we will need time O(ln^a(u)) so this method will be better than other that goes like O(t^a).