MPI design about prime number and twin number (C++ and python)

MPI: message exchange in the processes

in this article, I just use MPI_SEND and MPI_RECV.

C++ version

#include
#include 
#include 
#include     
#include      // ostream_iterator
#include "/usr/include/mpi/mpi.h"
const int MAX_NUMBERS = 100;
using namespace std;
int prime_number(int n)
{
    int i;
    
    if(n < 2 ) return 0;
    for(i = 2; i < n; i++)
    {
        if( n % i == 0)
        return 0;
    }
    return 1;
}


int find_min_prime(int number, int rank)
{
    int temp;
    int check_number;

    temp = int(number / 8);
    if( 8 * temp + 2 * rank + 1 <= number )
            temp = temp + 1; 
    while (1)
    {
        check_number = temp * 8 + 2 * rank + 1;
        if (prime_number(check_number))
            break;
        temp += 1 ;
    }
    return check_number;

}



int find_twin_number(int number, int rank)
{
    int n;

    while(1)
    {
        n = find_min_prime(number, rank);
        if( prime_number(n+2))
            return (n,n+2);
        else
            number += 1;
    }


}



vector count_twin(int number, int rank)
{
    int bottom;
    int above;
    int n;

    bottom = rank;
    above = number;
    vector< int> list;
    int * twin = new int[100]();
    int i = 0;

    while(1)
    {
        n = find_min_prime(bottom,rank);
        if (n + 2 > above)
            break;
        if (prime_number(n+2))
            {
                    list.push_back(n);
            }
        bottom += 1;
    
    }

    std::vector::iterator it;
    it = std::unique (list.begin(), list.end());   // 10 20 30 20 10 ?  ?  ?  ?
    list.resize( std::distance(list.begin(),it) ); // 10 20 30 20 10

    return list;
}
    



int main(int argc, char* argv[])
{
    int a ;
    int prime;
    int state = 0;
    int number_amount;
    vector list;
    vector un_list;
    vector< int> list_prime_number;
    vector< int> list_twin_number;
    int numprocs, myid, source;
    MPI_Init(&argc, &argv);
    MPI_Comm_rank(MPI_COMM_WORLD, &myid);
    MPI_Comm_size(MPI_COMM_WORLD, &numprocs);

    int number = 20;
    int message;
    if (myid == 4) 
    { 
        for(int i = 0; i<4; i++)
        { 
            MPI_Send(&number, 1, MPI_INT, i, 11,MPI_COMM_WORLD);
            cout<< "send " << number << " to processes "<< i <<" for problem 3"<< endl;
        }
        for(int i = 0; i<4; i++)
        {   
            MPI_Recv(&message, 1, MPI_INT, i, 12,MPI_COMM_WORLD,NULL);         
            list_prime_number.push_back(message);
            MPI_Recv(&message, 1, MPI_INT, i, 13,MPI_COMM_WORLD,NULL);
            list_twin_number.push_back(message);
        }
         int least_prime_number = *min_element(list_prime_number.begin(),list_prime_number.end());
         int least_twin_number = *min_element(list_twin_number.begin(),list_twin_number.end());
        cout<< "the least  prime number  is " << least_prime_number < twin_list;
   

     if (myid == 4) 
     {  
        // MPI_Status status;

        for(int i = 0;i < 4;i++) 
            {        
                   vector list2(MAX_NUMBERS);
                    MPI_Recv(&list2[0],  MAX_NUMBERS, MPI_INT, i, 14,MPI_COMM_WORLD,NULL);
                    for(int f = 0;f

python version

from mpi4py import MPI
import numpy as np
import argparse

comm = MPI.COMM_WORLD
rank = comm.Get_rank()
size = comm.Get_size()

parser = argparse.ArgumentParser()
parser.add_argument('--n', nargs='?', type=int, default=50,
                help='must be int')
arg = parser.parse_args()
n = arg.n



def prime_number(n):
    if n < 2 :
        return False
    for i in range(2,n):
        if n%i == 0:
            return False
    return True

def find_min_prime(number,rank):
    temp = number // 8 
    if 8 * temp + 2 * rank + 1 <= number :
        temp = temp + 1 
    while (1):
        check_number = temp * 8 + 2 * rank + 1
        # print(check_number)
        if prime_number(check_number):
            break
        temp += 1 
    return check_number


def find_twin_number(number, rank):
    while(1):
        n = find_min_prime(number, rank)
        if prime_number(n+2):
            return (n,n+2)
        else:
            number += 1


def count_twin(number, rank):
    bottom = int(rank)
    above = int(number)
    twin = []
    while(1):
        n = find_min_prime(bottom,rank)
        if n + 2 > above:
            break
        if prime_number(n+2):
            if (n,n+2) not in twin:
                twin.append ((n,n+2))
        bottom += 1
    return twin

            

if rank == 4:
    data = int(n) 
    for i in range(4):
        comm.isend(data, dest=i, tag=11)                           
        print("process {} immediate send {}...for problem 2".format(rank, data))
else:
#     for rank in range(4)
    data_count_twin =  count_twin(n,rank)
    data = comm.recv(source=4, tag=11)                         
    print("process {} recv {}...".format(rank, data)) 
    # data = data + 2 * rank +1 
    prime_number,twin_number = find_min_prime(data,rank),find_twin_number(data,rank)
    data = {'prime_number':prime_number,'twin_number':twin_number}
    comm.isend(data, dest=4, tag=12)
    print("process {} immediate send {}... for problem 4".format(rank, data))
  #  print('rank',rank, 'count', data_count_twin)
    comm.isend(data_count_twin, dest=4, tag=13)
    print("process {} immediate send {}... for problem 5".format(rank, data_count_twin))


data_twin = []
data_fin = []
if rank == 4:
    for i in range(4):
        temp = comm.recv(source = i, tag = 12)
        data_fin.append(temp)                           
        print("process {} immediate recv {}...".format(rank, temp))    


    least_min_twin = min([i['twin_number'][0] for i in data_fin])
    print('min_prime_number: ',min([i['prime_number'] for i in data_fin]), 'min_twin_number:  ',(least_min_twin,least_min_twin+2))

    for i in range(4):
        data_twin.extend(comm.recv(source = i, tag = 13))
    data_count = list(set(data_twin))
    print('the total number of twin numbers less than n: ',len(data_count))
    print(data_count)