The code below works, but when I try to run it using P17 the compiler throws an
error about the `gcd` proc. Using P17 causes `gcd` to be called on the order of
250,000 times, as `modpg = 510510`
Here's the code.
# Create constant parameters for chosen PG at compile time
proc genPGparameters(prime: int): (int, int, int, seq[int]) =
echo("generating parameters for P", prime)
let primes = [2, 3, 5, 7, 11, 13, 17, 19, 23]
var modpg = 1; var excluded_primescnt = 0
for prm in primes:
excluded_primescnt += 1; modpg *= prm; if prm == prime: break
var pc = 3; var residues: seq[int]; residues = @[]
while pc < modpg:
if gcd(modpg, pc) == 1: residues.add(pc)
pc += 2
residues.add(modpg + 1)
let rescnt = residues.len
result = (modpg, rescnt, excluded_primescnt, residues)
# Generate at compile time the parameters for P17
const parameters = genPGparameters(17)
Here's the relevant compiler output.
generating parameters for P17
stack trace: (most recent call last)
ssozp17x1d5bparnew128.nim(59)
ssozp17x1d5bparnew128.nim(52) genPGparameters
lib/pure/math.nim(439) gcd
lib/pure/math.nim(439, 15) Error: interpretation requires too many
iterations
➜ nim
I can't see how `gcd` could care how many times it's being called, so it seems
it must be the compiler not liking it being called past a certain number.
Whatever the reason, how do I get this code to finish compiling?
