Gfrktyl

I am trying to find all primes less than 2,000,000 and sum them together. My code currently takes 1'36" to run. Is there a faster way to get my solution?

The logic I am following in this code is make a list of all primes I have found. Then check that every odd number less than 2,000,000 is not divisible by any of the primes in my list. If that is the case I am calling the number prime.

package main                                          



import ("fmt"                                         

"time"                                                

)                                                     



func find_primes(max int) int {                     

    // list of all primes that we find                

    var primes int                                  

    primes = append(primes, 2)                        



    var is_prime = true                               

    for i:=3; i<=max; i++ {                           

        is_prime = false                              

        // only odds can be prime                     

        if i%2 != 0 {                                 

            is_prime = true                           

            // should not be divisible by any previous

            // prime numbers                          

            for _, x := range primes {                

                if i%x == 0 {                         

                    is_prime = false                  

                    break                             

                }                                     

            }                                         

        }                                             

        if is_prime {                                 

            primes = append(primes, i)                

        }                                             

    }                                                 

    return primes                                     

}                                                     



// just sume up all of the primes                     

func sum_primes(primes int) int {                   

    var total int = 0                                 

    for _, x := range primes {                        

        total = total + x                             

    }                                                 

    return total                                      

}                                                     



func main() {                                         

    start := time.Now()                               

    // find all primes less than 2,000,000            

    primes := find_primes(2000000)                    

    sum := sum_primes(primes)                         

    fmt.Println(sum)                                  

    t := time.Now()                                   

    elapsed := t.Sub(start)                           

    fmt.Println(elapsed)                              

}