Questions tagged [primes]
Primes or prime numbers are numbers which are divisible only by themselves and one, starting with 2, 3, 5, 7, 11.... They are commonly used in encryption and hashing algorithms.
717
questions
3
votes
1
answer
103
views
Miller-Rabin implementation is very slow
I implemented the Miller-Rabin-Primetest in python3. But I have the feeling it is very slow. I know that there are faster version in gmpy2 package, but I want to compare it with another code I have in ...
1
vote
2
answers
85
views
Miller-Rabin prime test
I have an implementation of the Miller-Rabin prime test, coded in Python 3.
I want to use that as a comparison to a prime test which I coded myself.
Unfortunately I have no idea how "fast" ...
9
votes
1
answer
273
views
Construct a performant sieve of Atkin in Rust
I have implemented the sieve of Atkin in Rust. It can find all primes till 1,000,000,000 in 4.5 s using 34.4 MiB on my 1.4 GHz machine. This is a direct implementation (with some optimisations made ...
6
votes
2
answers
900
views
C code for finding prime numbers
I have created a program to find prime numbers up to the 32nd power of 2. It uses the sieve of Eratosthenes. I would appreciate it if you could let me know any bugs or improvements I can make.
...
1
vote
1
answer
83
views
Project Euler 10(Python) | Summation of Primes
This is my Python3 code which solved the 10th problem of Project Euler. I haven't passed the last 2 time limit test cases.
...
3
votes
1
answer
253
views
Project Euler 60: Prime Pair Sets
Project Euler Prime Pair Sets:
The primes 3, 7, 109, and 673 are quite remarkable. By taking any two primes and concatenating them in any order the result will always be prime.
For example, taking 7 ...
3
votes
1
answer
66
views
Find perfect and amicable numbers
I've been playing with perfect, amicable and social numbers lately, and created a class for investigating these. At present, it has functions to return the perfect and amicable numbers in a specified ...
4
votes
2
answers
995
views
Miller-Rabin Primality Test in Python
I have the following implementation of the Miller-Rabin test in Python:
...
4
votes
2
answers
699
views
Performance of Haskell prime sieve
I have this code, which is a pseudo-Sieve of Eratosthenes for generating primes:
...
3
votes
1
answer
146
views
Hunting for the 100,001st prime in Rust
Most of my programming experience is in Python, but my first language was C, and I was intrigued by the combination which Rust offers: a streamlined syntax and no manual memory management, but with ...
2
votes
2
answers
126
views
generate prime factors via wheel factorization
I want to factor random values of n that range from uint.MinValue to uint.MaxValue as ...
3
votes
1
answer
118
views
Prime sieve in Rust
Using Sieve of Eratosthenes, I created a function that returns a vector of primes up to given limit.
...
17
votes
4
answers
2k
views
Make an image where pixels are colored if they are prime
This code creates a black-and-white image of variable size where the n-th pixel is white if n is a prime number and black if it isn't. It works, but I wonder if it is well written or if it could be ...
3
votes
1
answer
186
views
Find factor pairs of an integer in Rust
I'm trying to efficiently generate all pairs of factors of a number n.
For example, when n=27, the factor pairs are (1, 27), (3, 9), (9, 3), (27, 1)
The order in which the pairs are found is not ...
1
vote
0
answers
79
views
Strong Goldbach Conjecture with set implementation
I have devised my own version for a Goldbach verification project which uses sets to compare already sieved primes. My implementation also uses generators to "sieve a segment" since storing ...
4
votes
1
answer
507
views
Prime factorization algorithm by using the multiprocessing module of Python
I may introduce a Python code of prime factorization which is from my personal project that I'm working on.
...
1
vote
1
answer
124
views
Numpy segmented Sieve Of Eratosthenes
For the segmented Sieve Of Eratosthenes, I have devised the following code provided. And I understand that it is not the best implementation; However, it should be much quicker than what it is now. ...
1
vote
1
answer
213
views
Find primes using Wilson's Theorem
The following code is an instantiation of wilson's theorem. It uses a simple factorial and division theorem to check for primality. My issue is with the performance of the code, and there are two most ...
5
votes
1
answer
81
views
Möbius function using iterators for prime factors
While working on Project Euler, I have come across a few questions involving usage of the little omega function, big omega function, and Möbius function.
My prior code wrote factors into an array and ...
2
votes
1
answer
119
views
Multithreaded segmented Sieve of Eratosthenes
I am fairly new to Rust and thought a good way to practice would be to write a multithreaded segmented Sieve of Eratosthenes. It performs ok (searches ten-billion numbers in about 11 seconds on my ...
1
vote
1
answer
167
views
Euler's totient function for large numbers
I made this algorithm to compute Euler's totient function for large numbers. A sieve is used.
...
1
vote
0
answers
187
views
Benchmarking an improved wheel sieve
I followed your answers for my last questions (1st 2nd) and I came up with these new versions of my codes but I face some difficulties to measure the efficiency of my code, I use chrono library to ...
2
votes
1
answer
304
views
Prime sieve for large numbers
I state that I am not an expert and that certainly the code can be improved.
I made this prime number sieve to be able to handle large numbers.
The basic idea is to write a number p=r+bW*k where r is ...
0
votes
1
answer
196
views
Find factors of a Mersenne number
On RosettaCode I found this C++ version of modPow (compute 2ᵖ mod n) to find the factors of a Mersenne number.
...
0
votes
2
answers
699
views
Next level Improved Sieve of Eratosthenes
This is the next development for the Sieve of Eratosthenes algorithm, where all the multiples of 2,3 and 5 are eliminated, which will not take any memory or time.
As my last question Improved Sieve of ...
8
votes
7
answers
4k
views
Improved Sieve of Eratosthenes
How can I get to a perfect coding for this algorithm?
I made the mathematical theorem, which is a development of the Sieve of Eratosthenes algorithm. I might use some help in coding.
You can find the ...
4
votes
2
answers
190
views
Project Euler #51: "Prime digit replacements" in Rust
Problem: https://projecteuler.net/problem=51
"Find the smallest prime which, by replacing part of the number (not necessarily adjacent digits) with the same digit, is part of an eight prime ...
3
votes
1
answer
110
views
Fast way to compute a^d mod n
For a Miller-Rabin primality test I need a fast way to compute a^d mod n.
Where a is one of 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, ...
0
votes
0
answers
136
views
Sieve of Atkin C#
I don't fully understand how to make the Sieve of Atkin faster than the most ancient sieve.
All implementations I found online where slower than the one I made, but still It isn't faster than ...
4
votes
2
answers
1k
views
Calculate the first largest factor of 600851475143
ٍProblem description:
The prime factors of 13195 are 5, 7, 13 and 29. Largest prime factor 13195 is 29.
What is the largest prime factor of the number 600851475143 ?
Prime Factor:
any of the prime ...
1
vote
0
answers
116
views
Count SemiPrimes task from Codility
I'm trying to solve the following exercise from codility:
A prime is a positive integer X that has exactly two distinct
divisors: 1 and X. The first few prime integers are 2, 3, 5, 7, 11 and
13.
A ...
1
vote
2
answers
207
views
Clojure Prime Numbers from 1 to 1000
I am a beginner to Clojure and I made a little script that prints out every prime number from 1 to 1000. Let me know if there are any improvements that I can make:
...
3
votes
1
answer
155
views
A simple JavaScript function that does prime factorization
This is a simple JavaScript function that does prime factorization.
I wrote it on an Android phone with online editor (I don't have access to computers in night time):
Code:
...
2
votes
3
answers
362
views
Find prime numbers
I wanted to create a program that lists all prime numbers to a given upper bound and that will also provide the amount of primes in the set. After many hours of trial and error I was able to solve it.
...
3
votes
0
answers
245
views
Prime number generator in lisp
My implementation is based on the incremental prime sieve described on Wikipedia. I'm relatively new to lisp so I would appreciate any comments on my coding style or on the algorithm.
The below code ...
0
votes
0
answers
53
views
calculating all prime numbers up to a given number
This program calculates all prime numbers up to n. However it runs pretty slowly.
I was wondering if there was any optimisations I could make.
...
1
vote
1
answer
58
views
C code for discovering numbers with interesting/beautiful/symmetric properties
Below is a C code that generates 1000 random positive integers, for each number we check primality, palindromic property, and the square root of the sum of the digits. The purpose is to find/discover ...
3
votes
2
answers
154
views
Factor 999999 numbers as fast as possible
My code finds the prime factorization of numbers, ordering the prime numbers from least to greatest.
It prints a list of 999999 prime factorizations (which can be changed if you edit the function call ...
1
vote
0
answers
660
views
MIPS-32 assembly: Determine if n is prime
I'm new to assembly and I'm learning on my own, so I'd appreciate the feedback. My priorities are correctness (on all MIPS-32 with sllv) > speed > readability ...
2
votes
1
answer
165
views
Sieve of Eratosthenes in F#
after looking at the pseudocode for the Sieve of Eratosthenes on wikipedia I tried implementing a similar version using F#. The code runs just fine, that is, it returns all prime numbers up until a ...
3
votes
2
answers
388
views
Prime numbers iterator
I am not familiar with iterators. I am confused with the traits approach and the traditional one. I don't know which one I should use in 2021.
I wrote a minimal ...
3
votes
1
answer
904
views
Average prime number from array- Javascript
My mission is to solve this:
Write a function that will take an array of numbers, and will return the average of all numbers in the array that are prime number.
So far I wrote this:
...
3
votes
2
answers
194
views
Generating prime numbers quickly in rust
I am attempting to re-implement a postponed sieve algorithm for generating prime numbers in Rust. I am able to make a solution that works, but I have to use a couple of ...
1
vote
2
answers
140
views
Improving Project Euler code problem #10
So, I just finished Problem 10 on Project Euler, but it took about 3 to 4 minutes for my output to come out, due to bad coding, I guess, any suggestions on how could I optimize my code?
Question
The ...
4
votes
4
answers
213
views
My prime number generation program in Python
So I did my own take (I wrote my own algorithm) for generating prime numbers from 1 to 1000.
...
0
votes
2
answers
202
views
0
votes
2
answers
191
views
A function to find all the primes between two numbers whose reverse is also a prime and doesn't include palindrome, in JS
I am trying to solve a challenge in which I have to write a function that takes in two numbers as arguments and returns an array containing numbers between them which are prime and their reverse is ...
13
votes
1
answer
335
views
Sieve of Eratosthenes in Vyxal
I'm trying to learn the golfing language Vyxal because I occasionally contribute to it, and I'm slightly ashamed I can't even use it. To do this, I started with implementing the Sieve of Eratosthenes ...
3
votes
2
answers
509
views
Python – return list (or not?) of prime numbers between two numbers
I'm trying to learn how to write code well in Python. I've been tinkering with a function that will return a list of all prime numbers between the two parameters. This is the best I could come up with ...
1
vote
3
answers
204
views
Count prime numbers whose rotations are all prime
This code solves Project Euler problem 35:
The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime. There are thirteen such primes ...