rijumptable.py

#!/usr/bin/env python3

# rsm :: Random Sampling Mathematics
# Copyright (c) 2018 Michał Siejak
# Released under the MIT license; see LICENSE file for details

import math

def primes(N):
    p = [2, 3]
    np = p[-1] + 2
    while len(p) < N:
        is_prime = True
        for divisor in range(2, int(math.sqrt(np)) + 1):
            if np % divisor == 0:
                is_prime = False
                break
        if is_prime:
            p.append(np)
        np += 2
    return p

def generate(N):
    assert N >= 3
    print("// Generated by rijumptable.py for N={}".format(N))
    for index, p in enumerate(primes(N)[2:]):
        print("case {}: return radical_inverse_scrambled<T>({}, perm, value);".format(index + 2, p))

def main():
    import sys, argparse

    parser = argparse.ArgumentParser(description="Generate radical inverse jump table for RSM library.")
    parser.add_argument("N", nargs='?', type=int, default=128, help="Maximum sampling dimension to support with the generated table (default: 128, min: 3)")
    args = parser.parse_args()

    if args.N >= 3:
        generate(args.N)
    else:
        print("error: maximum sampling dimension needs to be at least 3", file=sys.stderr)
        sys.exit(1)

if __name__ == "__main__":
    main()