RosettaCodeData/Task/Miller-Rabin-primality-test/FreeBASIC/miller-rabin-primality-test...

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' version 05-04-2017
' compile with: fbc -s console
' TRUE/FALSE are built-in constants since FreeBASIC 1.04
' But we have to define them for older versions.
#Ifndef TRUE
#Define FALSE 0
#Define TRUE Not FALSE
#EndIf
#Include Once "gmp.bi"
#Macro big_int(a)
Dim As Mpz_ptr a = Allocate( Len( __mpz_struct))
Mpz_init(a)
#EndMacro
Dim Shared As __gmp_randstate_struct rnd_
Function miller_rabin(big_n As Mpz_ptr, num_of_tests As ULong) As Byte
If mpz_cmp_ui(big_n, 1) < 1 Then
Print "Numbers smaller then 1 not allowed"
Sleep 5000
End If
If mpz_cmp_ui(big_n, 2) = 0 OrElse mpz_cmp_ui(big_n, 3) = 0 Then
Return TRUE ' 2 = prime , 3 = prime
End If
If mpz_tstbit(big_n, 0) = 0 Then Return FALSE ' even number, no prime
Dim As ULong r, s
Dim As Byte return_value = TRUE
big_int(n_1) : big_int(n_2) : big_int(a) : big_int(d) : big_int(x)
mpz_sub_ui(n_1, big_n, 1) : mpz_sub_ui(n_2, big_n, 2) : mpz_set(d, n_1)
While mpz_tstbit(d, 0) = 0
mpz_fdiv_q_2exp(d, d, 1)
s += 1
Wend
While num_of_tests > 0
num_of_tests -= 1
mpz_urandomm(a, @rnd_, n_2)
mpz_add_ui(a, a, 2)
mpz_powm(x, a, d, big_n)
If mpz_cmp_ui(x, 1) = 0 Or mpz_cmp(x, n_1) = 0 Then Continue While
For r = 1 To s -1
mpz_powm_ui(x, x, 2, big_n)
If mpz_cmp_ui(x, 1) = 0 Then
return_value = FALSE
Exit While
End If
If mpz_cmp(x, n_1) = 0 Then Continue While
Next
If mpz_cmp(x, n_1) <> 0 Then
Return_value = FALSE
Exit while
End If
Wend
mpz_clear(n_1) : mpz_clear(a) : mpz_clear(d)
mpz_clear(n_2) : mpz_clear(x)
Return return_value
End Function
' ------=< MAIN >=------
Dim As Long x
Dim As String tmp
Dim As ZString Ptr gmp_str : gmp_str = Allocate(1000000)
big_int(big_n)
Randomize Timer
gmp_randinit_mt(@rnd_)
For x = 0 To 200 'create seed for random generator
tmp += Str(Int(Rnd * 10))
Next
Mpz_set_str(big_n, tmp, 10)
gmp_randseed(@rnd_, big_n) ' seed the random number generator
For x = 2 To 100
mpz_set_ui(big_n, x)
If miller_rabin(big_n, 5) = TRUE Then
Print Using "####"; x;
End If
Next
Print : Print
For x = 2 To 3300
mpz_set_ui(big_n, 1)
mpz_mul_2exp(big_n, big_n, x)
mpz_sub_ui(big_n, big_n, 1)
If miller_rabin(big_n, 5) = TRUE Then
gmp_str = Mpz_get_str(0, 10, big_n)
Print "2^";Str(x);"-1 = prime"
End If
Next
gmp_randclear(@rnd_)
mpz_clear(big_n)
DeAllocate(gmp_str)
' empty keyboard buffer
Print : While Inkey <> "" : Wend
Print : Print "hit any key to end program"
Sleep
End