func TestCoprime(t *testing.T) {
ps := []int{
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47,
127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181,
877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953,
2089, 2099, 2111, 2113, 2129, 2131, 2137, 2141, 2143, 2153,
9857, 9859, 9871, 9883, 9887, 9901, 9907, 9923, 9929, 9931,
1000003, 1000033, 1000037,
}
// Distinct primes are always relatively coprime
for i, p := range ps {
for j := 0; j <= i; j++ {
q := ps[j]
got := primes.Coprime(p, q)
want := p != q
if got != want {
t.Errorf("Coprime(%d,%d) == %v, want %v", p, q, got, want)
}
}
}
// Numbers sharing a common factor are never relatively coprime
factors := []int64{2, 5, 19, 47, 137, 877, 2089, 9931}
for i, p := range ps {
for j := 0; j <= i; j++ {
q := ps[j]
for _, f := range factors {
a := f * int64(p)
b := f * int64(q)
if a <= math.MaxInt32 && b <= math.MaxInt32 {
if primes.Coprime(int(a), int(b)) {
t.Errorf("Coprime(%d,%d) == true, want false", a, b)
}
}
}
}
}
}
func ExampleCoprime() {
// Check which combinations are coprime
ns := []int{2, 3, 4, 5, 6}
for i, a := range ns {
for _, b := range ns[i+1:] {
if primes.Coprime(a, b) {
fmt.Printf("%d and %d are coprime\n", a, b)
}
}
}
// Output:
// 2 and 3 are coprime
// 2 and 5 are coprime
// 3 and 4 are coprime
// 3 and 5 are coprime
// 4 and 5 are coprime
// 5 and 6 are coprime
}
