Prime

Efficient primality testing for MoonBit BigInt.

Public API

• is_prime(n):
  • Uses is_small_prime for n < 10_000.
  • Uses is_probable_prime_bpsw for n >= 10_000.
• is_small_prime(n):
  • Exact primality check for Int values in [0, 10_000).
• is_probable_prime_bpsw(n):
  • Baillie-Pomerance-Selfridge-Wagstaff (BPSW) probable-prime test.
  • Fast in practice and has no known counterexample, but is still a probable-prime test.

Notes

• The small-number path is optimized with a precomputed prime table and a narrow lookup window.
• The large-number path combines Miller-Rabin (base 2) and strong Lucas-Selfridge.

Benchmark

$ moon bench -p kokic/prime/benchmarks --target native

name                        time (mean ± σ)         range (min … max) 
kokic/prime BPSW               1.36 ms ±   9.23 µs     1.35 ms …   1.37 ms  in 10 ×     74 runs
core/math is_probable_prime   17.80 ms ± 200.94 µs    17.50 ms …  17.98 ms  in 10 ×      6 runs