primality-test

Welcome. I am trying to implement MillerRabin test for checking if large given number is a prime. Here is my code: public static bool MillerRabinTest(BigInteger number) { BigInteger d; var n = number - 1; var s = FindK(n, out d); BigInteger a = 2; BigInteger y = Calc(a, d, number); //a^d mod number if (y != BigInteger.One && y != n) { for (var r = 1; r <= s - 1; r++) { y = Calc(y, 2, number); if (y == 1) return false; } if (y != n) return false; } return true; //it is probably prime } It is working fine for small Bigintegers. But if my programs needs to evalute numbers containing of more than

I am trying to check if a number is prime using recursion. I was required to use a recursive helper function, but I am not sure how I should implement it. I think I know the algorithm, but I've never tried to use a recursive helper function in Racket. This is my current thoughts: See if n is divisible by i = 2 Set i = i + 1 If i^2 <= n continue. If no values of i evenly divided n , then it must be prime. This is what I have so far... (define (is_prime n) (if (<= n 1) #f (if (= (modulo n 2) 0) #f ) What would be a good approach using a recursive helper function?? Thanks! Using a helper simply

I know the Miller–Rabin primality test is probabilistic. However I want to use it for a programming task that leaves no room for error. Can we assume that it is correct with very high probability if the input numbers are 64-bit integers (i.e. long long in C)? Miller–Rabin is indeed probabilistic, but you can trade accuracy for computation time arbitrarily. If the number you test is prime, it will always give the correct answer. The problematic case is when a number is composite, but is reported to be prime. We can bound the probability of this error using the formula on Wikipedia : If you

I have the following code which determines whether a number is prime: public static boolean isPrime(int n){ boolean answer = (n>1)? true: false; for(int i = 2; i*i <= n; ++i) { System.out.printf("%d\n", i); if(n%i == 0) { answer = false; break; } } return answer; } How can I determine the big-O time complexity of this function? What is the size of the input in this case? Think about the worst-case runtime of this function, which happens if the number is indeed prime. In that case, the inner loop will execute as many times as possible. Since each iteration of the loop does a constant amount of

Hello I have created this program to check if a number is a prime number. It works but for some reason says that 999 is a prime number. Where is my mistake. It would be great if someone explained. Thank You! Here is my program: number = raw_input('Enter a Number: ') nnumber = int(number) prime_range = range(2, nnumber) for x in prime_range: if nnumber % x == 0: print 'Not a Prime Number!' break else: print 'Prime Number!' break Trace it. x starts with 2 , then tests 999 % 2 ; it is 1 , so else is executed, "Prime number!" is printed, and loop is broken out of. Program ends. Instead, you need

I would just like to ask if this is a correct way of checking if number is prime or not? because I read that 0 and 1 are NOT a prime number. int num1; Console.WriteLine("Accept number:"); num1 = Convert.ToInt32(Console.ReadLine()); if (num1 == 0 || num1 == 1) { Console.WriteLine(num1 + " is not prime number"); Console.ReadLine(); } else { for (int a = 2; a <= num1 / 2; a++) { if (num1 % a == 0) { Console.WriteLine(num1 + " is not prime number"); return; } } Console.WriteLine(num1 + " is a prime number"); Console.ReadLine(); } Soner Gönül var number; Console.WriteLine("Accept number:"); number