WeixiangYan/CodeTransOcean huggingface dataset:
Task: Roots of a quadratic function




Go: package main

import (
    "fmt"
    "math"
)

func qr(a, b, c float64) ([]float64, []complex128) {
    d := b*b-4*a*c
    switch {
    case d == 0:
        
        return []float64{-b/(2*a)}, nil
    case d > 0:
        
        if b < 0 {
            d = math.Sqrt(d)-b
        } else {
            d = -math.Sqrt(d)-b
        }
        return []float64{d/(2*a), (2*c)/d}, nil
    case d < 0:
        

        den := 1/(2*a)
        t1 := complex(-b*den, 0)
        t2 := complex(0, math.Sqrt(-d)*den)
        return nil, []complex128{t1+t2, t1-t2}
    }
    
    return []float64{d}, nil
}

func test(a, b, c float64) {
    fmt.Print("coefficients: ", a, b, c, " -> ")
    r, i := qr(a, b, c)
    switch len(r) {
    case 1:
        fmt.Println("one real root:", r[0])
    case 2:
        fmt.Println("two real roots:", r[0], r[1])
    default:
        fmt.Println("two complex roots:", i[0], i[1])
    }
}

func main() {
    for _, c := range [][3]float64{
        {1, -2, 1},
        {1, 0, 1},
        {1, -10, 1},
        {1, -1000, 1},
        {1, -1e9, 1},
    } {
        test(c[0], c[1], c[2])
    }
}




Python: 

import math
import cmath
import numpy

def quad_discriminating_roots(a,b,c, entier = 1e-5):
    
    discriminant = b*b - 4*a*c
    a,b,c,d =complex(a), complex(b), complex(c), complex(discriminant)
    root1 = (-b + cmath.sqrt(d))/2./a
    root2 = (-b - cmath.sqrt(d))/2./a
    if abs(discriminant) < entier:
        return "real and equal", abs(root1), abs(root1)
    if discriminant > 0:
        return "real", root1.real, root2.real
    return "complex", root1, root2

def middlebrook(a, b, c):
    try:
        q = math.sqrt(a*c)/b
        f = .5+ math.sqrt(1-4*q*q)/2
    except ValueError:
        q = cmath.sqrt(a*c)/b
        f = .5+ cmath.sqrt(1-4*q*q)/2
    return (-b/a)*f, -c/(b*f)

def whatevery(a, b, c):
    try:
        d = math.sqrt(b*b-4*a*c)
    except ValueError:
        d = cmath.sqrt(b*b-4*a*c)
    if b > 0:
        return div(2*c, (-b-d)), div((-b-d), 2*a)
    else:
        return div((-b+d), 2*a), div(2*c, (-b+d))

def div(n, d):
    
    try:
        return n/d
    except ZeroDivisionError:
        if n:
            return n*float('inf')
        return float('nan')

testcases = [
    (3, 4, 4/3),    
    (3, 2, -1),     
    (3, 2, 1),      
    (1, -1e9, 1),   
    (1, -1e100, 1),
    (1, -1e200, 1),
    (1, -1e300, 1),
]

print('Naive:')
for c in testcases:
    print("{} {:.5} {:.5}".format(*quad_discriminating_roots(*c)))

print('\nMiddlebrook:')
for c in testcases:
    print(("{:.5} "*2).format(*middlebrook(*c)))

print('\nWhat Every...')
for c in testcases:
    print(("{:.5} "*2).format(*whatevery(*c)))

print('\nNumpy:')
for c in testcases:
    print(("{:.5} "*2).format(*numpy.roots(c)))
Task: Factors of a Mersenne number

C: int isPrime(int n){
	if (n%2==0) return n==2;
	if (n%3==0) return n==3;
	int d=5;
	while(d*d<=n){
		if(n%d==0) return 0;
		d+=2;
		if(n%d==0) return 0;
		d+=4;}
	return 1;}

main() {int i,d,p,r,q=929;
	if (!isPrime(q)) return 1; 
	r=q;
	while(r>0) r<<=1;
	d=2*q+1;
	do { 	for(p=r, i= 1; p; p<<= 1){
			i=((long long)i * i) % d;
			if (p < 0) i *= 2;
			if (i > d) i -= d;}
		if (i != 1) d += 2*q;
		else break;
	} while(1);
	printf("2^%d - 1 = 0 (mod %d)\n", q, d);}


C++: #include <iostream>
#include <cstdint>

typedef uint64_t integer;

integer bit_count(integer n) {
    integer count = 0;
    for (; n > 0; count++)
        n >>= 1;
    return count;
}

integer mod_pow(integer p, integer n) {
    integer square = 1;
    for (integer bits = bit_count(p); bits > 0; square %= n) {
        square *= square;
        if (p & (1 << --bits))
            square <<= 1;
    }
    return square;
}

bool is_prime(integer n) {
    if (n < 2)
        return false;
    if (n % 2 == 0)
        return n == 2;
    for (integer p = 3; p * p <= n; p += 2)
        if (n % p == 0)
            return false;
    return true;
}

integer find_mersenne_factor(integer p) {
    for (integer k = 0, q = 1;;) {
        q = 2 * ++k * p + 1;
        if ((q % 8 == 1 || q % 8 == 7) && mod_pow(p, q) == 1 && is_prime(q))
            return q;
    }
    return 0;
}

int main() {
    std::cout << find_mersenne_factor(929) << std::endl;
    return 0;
}
Task: Factors of a Mersenne number

C: int isPrime(int n){
	if (n%2==0) return n==2;
	if (n%3==0) return n==3;
	int d=5;
	while(d*d<=n){
		if(n%d==0) return 0;
		d+=2;
		if(n%d==0) return 0;
		d+=4;}
	return 1;}

main() {int i,d,p,r,q=929;
	if (!isPrime(q)) return 1; 
	r=q;
	while(r>0) r<<=1;
	d=2*q+1;
	do { 	for(p=r, i= 1; p; p<<= 1){
			i=((long long)i * i) % d;
			if (p < 0) i *= 2;
			if (i > d) i -= d;}
		if (i != 1) d += 2*q;
		else break;
	} while(1);
	printf("2^%d - 1 = 0 (mod %d)\n", q, d);}




Go: package main

import (
    "fmt"
    "math"
)



const qlimit = 2e8

func main() {
    mtest(31)
    mtest(67)
    mtest(929)
}

func mtest(m int32) {
    
    
    
    
    if m < 4 {
        fmt.Printf("%d < 4.  M%d not tested.\n", m, m)
        return
    }
    flimit := math.Sqrt(math.Pow(2, float64(m)) - 1)
    var qlast int32
    if flimit < qlimit {
        qlast = int32(flimit)
    } else {
        qlast = qlimit
    }
    composite := make([]bool, qlast+1)
    sq := int32(math.Sqrt(float64(qlast)))
loop:
    for q := int32(3); ; {
        if q <= sq {
            for i := q * q; i <= qlast; i += q {
                composite[i] = true
            }
        }
        if q8 := q % 8; (q8 == 1 || q8 == 7) && modPow(2, m, q) == 1 {
            fmt.Printf("M%d has factor %d\n", m, q)
            return
        }
        for {
            q += 2
            if q > qlast {
                break loop
            }
            if !composite[q] {
                break
            }
        }
    }
    fmt.Printf("No factors of M%d found.\n", m)
}


func modPow(b, p, m int32) int32 {
    pow := int64(1)
    b64 := int64(b)
    m64 := int64(m)
    bit := uint(30)
    for 1<<bit&p == 0 {
        bit--
    }
    for {
        pow *= pow
        if 1<<bit&p != 0 {
            pow *= b64
        }
        pow %= m64
        if bit == 0 {
            break
        }
        bit--
    }
    return int32(pow)
}
Task: Factors of a Mersenne number

C: int isPrime(int n){
	if (n%2==0) return n==2;
	if (n%3==0) return n==3;
	int d=5;
	while(d*d<=n){
		if(n%d==0) return 0;
		d+=2;
		if(n%d==0) return 0;
		d+=4;}
	return 1;}

main() {int i,d,p,r,q=929;
	if (!isPrime(q)) return 1; 
	r=q;
	while(r>0) r<<=1;
	d=2*q+1;
	do { 	for(p=r, i= 1; p; p<<= 1){
			i=((long long)i * i) % d;
			if (p < 0) i *= 2;
			if (i > d) i -= d;}
		if (i != 1) d += 2*q;
		else break;
	} while(1);
	printf("2^%d - 1 = 0 (mod %d)\n", q, d);}







Python: def is_prime(number):
    return True 

def m_factor(p):
    max_k = 16384 / p 
    for k in xrange(max_k):
        q = 2*p*k + 1
        if not is_prime(q):
            continue
        elif q % 8 != 1 and q % 8 != 7:
            continue
        elif pow(2, p, q) == 1:
            return q
    return None

if __name__ == '__main__':
    exponent = int(raw_input("Enter exponent of Mersenne number: "))
    if not is_prime(exponent):
        print "Exponent is not prime: %d" % exponent
    else:
        factor = m_factor(exponent)
        if not factor:
            print "No factor found for M%d" % exponent
        else:
            print "M%d has a factor: %d" % (exponent, factor)
Task: Factors of a Mersenne number

C: int isPrime(int n){
	if (n%2==0) return n==2;
	if (n%3==0) return n==3;
	int d=5;
	while(d*d<=n){
		if(n%d==0) return 0;
		d+=2;
		if(n%d==0) return 0;
		d+=4;}
	return 1;}

main() {int i,d,p,r,q=929;
	if (!isPrime(q)) return 1; 
	r=q;
	while(r>0) r<<=1;
	d=2*q+1;
	do { 	for(p=r, i= 1; p; p<<= 1){
			i=((long long)i * i) % d;
			if (p < 0) i *= 2;
			if (i > d) i -= d;}
		if (i != 1) d += 2*q;
		else break;
	} while(1);
	printf("2^%d - 1 = 0 (mod %d)\n", q, d);}








VB: 
    for i=1 to 59
        z=i
        if z=59 then z=929  
        if isPrime(z) then 
            r=testM(z)
            zz=left("M" & z & space(4),4)
            if r=0 then 
                Wscript.echo zz & " prime."
            else 
                Wscript.echo zz & " not prime, a factor: " & r
            end if
        end if
    next

function modPow(base,n,div)
    dim i,y,z
    i = n : y = 1 : z = base
    do while i
        if i and 1 then y = (y * z) mod div
        z = (z * z) mod div
        i = i \ 2
    loop
    modPow= y
end function

function isPrime(x)
    dim i
    if x=2 or x=3 or _
       x=5 or x=7 _
                  then isPrime=1: exit function
    if x<11       then isPrime=0: exit function
    if x mod 2=0  then isPrime=0: exit function
    if x mod 3=0  then isPrime=0: exit function
    i=5
    do
        if (x mod i)     =0 or _
           (x mod (i+2)) =0 _
                  then isPrime=0: exit function
        if i*i>x  then isPrime=1: exit function
        i=i+6
    loop
end function

function testM(x)
    dim sqroot,k,q
    sqroot=Sqr(2^x)
    k=1
    do
        q=2*k*x+1
        if q>sqroot then exit do
        if (q and 7)=1 or (q and 7)=7 then
            if isPrime(q) then
                if modPow(2,x,q)=1 then 
                    testM=q
                    exit function
                end if
            end if
        end if
        k=k+1
    loop
    testM=0 
end function
Task: Factors of a Mersenne number


C++: #include <iostream>
#include <cstdint>

typedef uint64_t integer;

integer bit_count(integer n) {
    integer count = 0;
    for (; n > 0; count++)
        n >>= 1;
    return count;
}

integer mod_pow(integer p, integer n) {
    integer square = 1;
    for (integer bits = bit_count(p); bits > 0; square %= n) {
        square *= square;
        if (p & (1 << --bits))
            square <<= 1;
    }
    return square;
}

bool is_prime(integer n) {
    if (n < 2)
        return false;
    if (n % 2 == 0)
        return n == 2;
    for (integer p = 3; p * p <= n; p += 2)
        if (n % p == 0)
            return false;
    return true;
}

integer find_mersenne_factor(integer p) {
    for (integer k = 0, q = 1;;) {
        q = 2 * ++k * p + 1;
        if ((q % 8 == 1 || q % 8 == 7) && mod_pow(p, q) == 1 && is_prime(q))
            return q;
    }
    return 0;
}

int main() {
    std::cout << find_mersenne_factor(929) << std::endl;
    return 0;
}



Go: package main

import (
    "fmt"
    "math"
)



const qlimit = 2e8

func main() {
    mtest(31)
    mtest(67)
    mtest(929)
}

func mtest(m int32) {
    
    
    
    
    if m < 4 {
        fmt.Printf("%d < 4.  M%d not tested.\n", m, m)
        return
    }
    flimit := math.Sqrt(math.Pow(2, float64(m)) - 1)
    var qlast int32
    if flimit < qlimit {
        qlast = int32(flimit)
    } else {
        qlast = qlimit
    }
    composite := make([]bool, qlast+1)
    sq := int32(math.Sqrt(float64(qlast)))
loop:
    for q := int32(3); ; {
        if q <= sq {
            for i := q * q; i <= qlast; i += q {
                composite[i] = true
            }
        }
        if q8 := q % 8; (q8 == 1 || q8 == 7) && modPow(2, m, q) == 1 {
            fmt.Printf("M%d has factor %d\n", m, q)
            return
        }
        for {
            q += 2
            if q > qlast {
                break loop
            }
            if !composite[q] {
                break
            }
        }
    }
    fmt.Printf("No factors of M%d found.\n", m)
}


func modPow(b, p, m int32) int32 {
    pow := int64(1)
    b64 := int64(b)
    m64 := int64(m)
    bit := uint(30)
    for 1<<bit&p == 0 {
        bit--
    }
    for {
        pow *= pow
        if 1<<bit&p != 0 {
            pow *= b64
        }
        pow %= m64
        if bit == 0 {
            break
        }
        bit--
    }
    return int32(pow)
}
Task: Factors of a Mersenne number


C++: #include <iostream>
#include <cstdint>

typedef uint64_t integer;

integer bit_count(integer n) {
    integer count = 0;
    for (; n > 0; count++)
        n >>= 1;
    return count;
}

integer mod_pow(integer p, integer n) {
    integer square = 1;
    for (integer bits = bit_count(p); bits > 0; square %= n) {
        square *= square;
        if (p & (1 << --bits))
            square <<= 1;
    }
    return square;
}

bool is_prime(integer n) {
    if (n < 2)
        return false;
    if (n % 2 == 0)
        return n == 2;
    for (integer p = 3; p * p <= n; p += 2)
        if (n % p == 0)
            return false;
    return true;
}

integer find_mersenne_factor(integer p) {
    for (integer k = 0, q = 1;;) {
        q = 2 * ++k * p + 1;
        if ((q % 8 == 1 || q % 8 == 7) && mod_pow(p, q) == 1 && is_prime(q))
            return q;
    }
    return 0;
}

int main() {
    std::cout << find_mersenne_factor(929) << std::endl;
    return 0;
}






Python: def is_prime(number):
    return True 

def m_factor(p):
    max_k = 16384 / p 
    for k in xrange(max_k):
        q = 2*p*k + 1
        if not is_prime(q):
            continue
        elif q % 8 != 1 and q % 8 != 7:
            continue
        elif pow(2, p, q) == 1:
            return q
    return None

if __name__ == '__main__':
    exponent = int(raw_input("Enter exponent of Mersenne number: "))
    if not is_prime(exponent):
        print "Exponent is not prime: %d" % exponent
    else:
        factor = m_factor(exponent)
        if not factor:
            print "No factor found for M%d" % exponent
        else:
            print "M%d has a factor: %d" % (exponent, factor)
Task: Factors of a Mersenne number


C++: #include <iostream>
#include <cstdint>

typedef uint64_t integer;

integer bit_count(integer n) {
    integer count = 0;
    for (; n > 0; count++)
        n >>= 1;
    return count;
}

integer mod_pow(integer p, integer n) {
    integer square = 1;
    for (integer bits = bit_count(p); bits > 0; square %= n) {
        square *= square;
        if (p & (1 << --bits))
            square <<= 1;
    }
    return square;
}

bool is_prime(integer n) {
    if (n < 2)
        return false;
    if (n % 2 == 0)
        return n == 2;
    for (integer p = 3; p * p <= n; p += 2)
        if (n % p == 0)
            return false;
    return true;
}

integer find_mersenne_factor(integer p) {
    for (integer k = 0, q = 1;;) {
        q = 2 * ++k * p + 1;
        if ((q % 8 == 1 || q % 8 == 7) && mod_pow(p, q) == 1 && is_prime(q))
            return q;
    }
    return 0;
}

int main() {
    std::cout << find_mersenne_factor(929) << std::endl;
    return 0;
}







VB: 
    for i=1 to 59
        z=i
        if z=59 then z=929  
        if isPrime(z) then 
            r=testM(z)
            zz=left("M" & z & space(4),4)
            if r=0 then 
                Wscript.echo zz & " prime."
            else 
                Wscript.echo zz & " not prime, a factor: " & r
            end if
        end if
    next

function modPow(base,n,div)
    dim i,y,z
    i = n : y = 1 : z = base
    do while i
        if i and 1 then y = (y * z) mod div
        z = (z * z) mod div
        i = i \ 2
    loop
    modPow= y
end function

function isPrime(x)
    dim i
    if x=2 or x=3 or _
       x=5 or x=7 _
                  then isPrime=1: exit function
    if x<11       then isPrime=0: exit function
    if x mod 2=0  then isPrime=0: exit function
    if x mod 3=0  then isPrime=0: exit function
    i=5
    do
        if (x mod i)     =0 or _
           (x mod (i+2)) =0 _
                  then isPrime=0: exit function
        if i*i>x  then isPrime=1: exit function
        i=i+6
    loop
end function

function testM(x)
    dim sqroot,k,q
    sqroot=Sqr(2^x)
    k=1
    do
        q=2*k*x+1
        if q>sqroot then exit do
        if (q and 7)=1 or (q and 7)=7 then
            if isPrime(q) then
                if modPow(2,x,q)=1 then 
                    testM=q
                    exit function
                end if
            end if
        end if
        k=k+1
    loop
    testM=0 
end function
Task: Factors of a Mersenne number




Go: package main

import (
    "fmt"
    "math"
)



const qlimit = 2e8

func main() {
    mtest(31)
    mtest(67)
    mtest(929)
}

func mtest(m int32) {
    
    
    
    
    if m < 4 {
        fmt.Printf("%d < 4.  M%d not tested.\n", m, m)
        return
    }
    flimit := math.Sqrt(math.Pow(2, float64(m)) - 1)
    var qlast int32
    if flimit < qlimit {
        qlast = int32(flimit)
    } else {
        qlast = qlimit
    }
    composite := make([]bool, qlast+1)
    sq := int32(math.Sqrt(float64(qlast)))
loop:
    for q := int32(3); ; {
        if q <= sq {
            for i := q * q; i <= qlast; i += q {
                composite[i] = true
            }
        }
        if q8 := q % 8; (q8 == 1 || q8 == 7) && modPow(2, m, q) == 1 {
            fmt.Printf("M%d has factor %d\n", m, q)
            return
        }
        for {
            q += 2
            if q > qlast {
                break loop
            }
            if !composite[q] {
                break
            }
        }
    }
    fmt.Printf("No factors of M%d found.\n", m)
}


func modPow(b, p, m int32) int32 {
    pow := int64(1)
    b64 := int64(b)
    m64 := int64(m)
    bit := uint(30)
    for 1<<bit&p == 0 {
        bit--
    }
    for {
        pow *= pow
        if 1<<bit&p != 0 {
            pow *= b64
        }
        pow %= m64
        if bit == 0 {
            break
        }
        bit--
    }
    return int32(pow)
}




Python: def is_prime(number):
    return True 

def m_factor(p):
    max_k = 16384 / p 
    for k in xrange(max_k):
        q = 2*p*k + 1
        if not is_prime(q):
            continue
        elif q % 8 != 1 and q % 8 != 7:
            continue
        elif pow(2, p, q) == 1:
            return q
    return None

if __name__ == '__main__':
    exponent = int(raw_input("Enter exponent of Mersenne number: "))
    if not is_prime(exponent):
        print "Exponent is not prime: %d" % exponent
    else:
        factor = m_factor(exponent)
        if not factor:
            print "No factor found for M%d" % exponent
        else:
            print "M%d has a factor: %d" % (exponent, factor)
Task: Factors of a Mersenne number




Go: package main

import (
    "fmt"
    "math"
)



const qlimit = 2e8

func main() {
    mtest(31)
    mtest(67)
    mtest(929)
}

func mtest(m int32) {
    
    
    
    
    if m < 4 {
        fmt.Printf("%d < 4.  M%d not tested.\n", m, m)
        return
    }
    flimit := math.Sqrt(math.Pow(2, float64(m)) - 1)
    var qlast int32
    if flimit < qlimit {
        qlast = int32(flimit)
    } else {
        qlast = qlimit
    }
    composite := make([]bool, qlast+1)
    sq := int32(math.Sqrt(float64(qlast)))
loop:
    for q := int32(3); ; {
        if q <= sq {
            for i := q * q; i <= qlast; i += q {
                composite[i] = true
            }
        }
        if q8 := q % 8; (q8 == 1 || q8 == 7) && modPow(2, m, q) == 1 {
            fmt.Printf("M%d has factor %d\n", m, q)
            return
        }
        for {
            q += 2
            if q > qlast {
                break loop
            }
            if !composite[q] {
                break
            }
        }
    }
    fmt.Printf("No factors of M%d found.\n", m)
}


func modPow(b, p, m int32) int32 {
    pow := int64(1)
    b64 := int64(b)
    m64 := int64(m)
    bit := uint(30)
    for 1<<bit&p == 0 {
        bit--
    }
    for {
        pow *= pow
        if 1<<bit&p != 0 {
            pow *= b64
        }
        pow %= m64
        if bit == 0 {
            break
        }
        bit--
    }
    return int32(pow)
}





VB: 
    for i=1 to 59
        z=i
        if z=59 then z=929  
        if isPrime(z) then 
            r=testM(z)
            zz=left("M" & z & space(4),4)
            if r=0 then 
                Wscript.echo zz & " prime."
            else 
                Wscript.echo zz & " not prime, a factor: " & r
            end if
        end if
    next

function modPow(base,n,div)
    dim i,y,z
    i = n : y = 1 : z = base
    do while i
        if i and 1 then y = (y * z) mod div
        z = (z * z) mod div
        i = i \ 2
    loop
    modPow= y
end function

function isPrime(x)
    dim i
    if x=2 or x=3 or _
       x=5 or x=7 _
                  then isPrime=1: exit function
    if x<11       then isPrime=0: exit function
    if x mod 2=0  then isPrime=0: exit function
    if x mod 3=0  then isPrime=0: exit function
    i=5
    do
        if (x mod i)     =0 or _
           (x mod (i+2)) =0 _
                  then isPrime=0: exit function
        if i*i>x  then isPrime=1: exit function
        i=i+6
    loop
end function

function testM(x)
    dim sqroot,k,q
    sqroot=Sqr(2^x)
    k=1
    do
        q=2*k*x+1
        if q>sqroot then exit do
        if (q and 7)=1 or (q and 7)=7 then
            if isPrime(q) then
                if modPow(2,x,q)=1 then 
                    testM=q
                    exit function
                end if
            end if
        end if
        k=k+1
    loop
    testM=0 
end function
Task: Factors of a Mersenne number

C: int isPrime(int n){
	if (n%2==0) return n==2;
	if (n%3==0) return n==3;
	int d=5;
	while(d*d<=n){
		if(n%d==0) return 0;
		d+=2;
		if(n%d==0) return 0;
		d+=4;}
	return 1;}

main() {int i,d,p,r,q=929;
	if (!isPrime(q)) return 1; 
	r=q;
	while(r>0) r<<=1;
	d=2*q+1;
	do { 	for(p=r, i= 1; p; p<<= 1){
			i=((long long)i * i) % d;
			if (p < 0) i *= 2;
			if (i > d) i -= d;}
		if (i != 1) d += 2*q;
		else break;
	} while(1);
	printf("2^%d - 1 = 0 (mod %d)\n", q, d);}





Java: import java.math.BigInteger;

class MersenneFactorCheck
{

  private final static BigInteger TWO = BigInteger.valueOf(2);
  
  public static boolean isPrime(long n)
  {
    if (n == 2)
      return true;
    if ((n < 2) || ((n & 1) == 0))
      return false;
    long maxFactor = (long)Math.sqrt((double)n);
    for (long possibleFactor = 3; possibleFactor <= maxFactor; possibleFactor += 2)
      if ((n % possibleFactor) == 0)
        return false;
    return true;
  }
  
  public static BigInteger findFactorMersenneNumber(int primeP)
  {
    if (primeP <= 0)
      throw new IllegalArgumentException();
    BigInteger bigP = BigInteger.valueOf(primeP);
    BigInteger m = BigInteger.ONE.shiftLeft(primeP).subtract(BigInteger.ONE);
    
    BigInteger maxFactor = BigInteger.ONE.shiftLeft((primeP + 1) >>> 1);
    BigInteger twoP = BigInteger.valueOf(primeP << 1);
    BigInteger possibleFactor = BigInteger.ONE;
    int possibleFactorBits12 = 0;
    int twoPBits12 = primeP & 3;
    
    while ((possibleFactor = possibleFactor.add(twoP)).compareTo(maxFactor) <= 0)
    {
      possibleFactorBits12 = (possibleFactorBits12 + twoPBits12) & 3;
      
      if ((possibleFactorBits12 == 0) || (possibleFactorBits12 == 3))
        if (TWO.modPow(bigP, possibleFactor).equals(BigInteger.ONE))
          return possibleFactor;
    }
    return null;
  }
  
  public static void checkMersenneNumber(int p)
  {
    if (!isPrime(p))
    {
      System.out.println("M" + p + " is not prime");
      return;
    }
    BigInteger factor = findFactorMersenneNumber(p);
    if (factor == null)
      System.out.println("M" + p + " is prime");
    else
      System.out.println("M" + p + " is not prime, has factor " + factor);
    return;
  }

  public static void main(String[] args)
  {
    for (int p = 1; p <= 50; p++)
      checkMersenneNumber(p);
    checkMersenneNumber(929);
    return;
  }
  
}