# Thomas

### self employed

Last seen: 4 months ago Active since 2019

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Submitted

A simple quaternion class
class with some basic operations on quaternions

Submitted

discrete logarithm
compute the discrete logarithm using Shank's algorithm

How to create an array of matrices?
function aM = arrayofmatrices(A,B,C) aM(:,:,1) = A; aM(:,:,2) = B; aM(:,:,3) = C; end This only works when A, B and C hav...

1 year ago | 0

Question

I try to find a general vector base for all magic squares of dimension n . Why does this program work for n = 3, but not vor n > 3?
The program below is supposed to find a general vector base for all magic squares of dimension n . Why does this program work fo...

1 year ago | 1 answer | 0

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How can i check if a matrix is magic square or not?
try: function ismagic = ismagic(M) %ISMAGIC checks if a matrix M is a magic square or not if size(M,1) ~= size(M,2) is...

1 year ago | 0

How can i create array of symbolic expressions?
does this help? function array_of_symbolicExpressions(mx) syms t y(t); y(t) = t^3+t^2; % just an example d = diff(y); ...

1 year ago | 0

Submitted

Simple Chess game
I tried to keep it "minimalistic", so strength isn't great.

Submitted

Two versions of Pollard's rho factorization algorithm
one version with Brent's style cycle detection, one without but using vectors and matrices

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sieve of Erathostenes
a simple number sieve, which could (in theory) run forever, because it does not require an interval to be sieved.

Question

why is this Matlab Code faster than the C++ code below? I want to understand what Matlab internally does better and faster than C++
why is this Matlab Code function primes = sieve_era2(N) % sieve of Erathostenes without upper bound of search space (could th...

2 years ago | 2 answers | 2

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find zeros of the Riemann zeta function
This function finds zeros of the Riemann zeta function on the critical line 0.5 + i*t in an interval von <= t <= bis

Submitted

Hashlife
a Matlab version of Gosper's hashlife

Question

Approximation of pi is "too precise" .
The function below should approximate pi adding about 2 digits of precision for increasing n. Why is piApprox2(3) exactly = pi ...

3 years ago | 1 answer | 0

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two ways to compute Riemanns prime counting function
one version which works (J2) and one which does not work (J1).

Question

When I start Matlab from the Desktop Icon or from the task bar, I get this error: "std::exception: Loading D:\Program Files\M...

3 years ago | 0 answers | 4

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convert integer to binary or binary to integer
convert a column vetor of integers to a column vector of binaries or vice versa

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zetaRS approximates Riemann's zeta(0.5 + i*t) for large t
Fast computation of Riemann's zeta function on the critical strip using the Riemann Siegel formula.

Question

using fzero with arrayfun searching for zeros inside an interval
I have a function f = @(x) -x.^2+4 with a zero at -2 and +2 using fzero(f, [-3, 1.9]) I get the (correct) zero inside the inte...

3 years ago | 1 answer | 0

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Fast approximation of Pi
Approximate Pi with 16th order convergence

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Create and run Turing machines
Some tools and examples for creating and simulating Turing machines and macro-Turing machines.

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More sophisticated check for endless loops, support for parallel execution and the use of macro-Turing-machines

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uncover the call structure of a recursive function call
recurse(tree) helps to uncover the call structure of a recursive function call.

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GaussLegendre
quick approximation of pi using the Gauss-Legendre algorithm

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two versions of the Euler-phi function
two brief implementations of the Eulerphi function

Question

Extract lines of a three dimensional matrix using an array of indices and NO for-loop
I have a three dimensional 10x5x2 array. Example: r(:,:,1) = [1 0 2 1 1; 2 0 3 1 1; 3 0 4 1 1; 4 0 1 1 -1; 5 0 -1 1 1; 1 1 3 1...

4 years ago | 1 answer | 0

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Recursive computation of the "uncomputable" Rado-function.

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Karatsuba algorithm for fast multiplication
Multiplication of "x" and "y" with Karatsuba method using base "base" x , y and base can be freely chosen

Submitted

Shor Algorithm for prime factoring
A Version of the Shor-Algorithm for prime Factoring. Please feel free to comment on it or recommend improvements.

Question

trying to compute Riemann's prime counting function J(x)
I am trying to compute Riemann's prime counting function J(x): J(x) should approximate the numbers of primes <= x using thi...

5 years ago | 2 answers | 0