yarrg/rssearch.c

   1 /**/
   2
   3 #include "rscommon.h"
   4
   5 DEBUG_DEFINE_DEBUGF(search);
   6 DEBUG_DEFINE_SOME_DEBUGF(filter,fildebugf);
   7
   8 typedef struct Neighbour {
   9   struct Neighbour *next;
  10   int islandid;
  11   int dist;
  12 } Neighbour;
  13
  14 static Neighbour **neighbours; /* neighbours[islandid]->islandid etc. */
  15 static sqlite3_stmt *ss_neigh;
  16
  17 static int ports[MAX_ROUTELEN];
  18
  19 static Neighbour *get_neighbours(int isle) {
  20   Neighbour **np= &neighbours[isle];
  21   Neighbour *head= *np;
  22   if (head) return head;
  23
  24   SQL_BIND(ss_neigh, 1, isle);
  25   while (SQL_STEP(ss_neigh)) {
  26     Neighbour *add= mmalloc(sizeof(*add));
  27     add->islandid= sqlite3_column_int(ss_neigh, 0);
  28     add->dist= sqlite3_column_int(ss_neigh, 1);
  29     add->next= head;
  30     head= add;
  31   }
  32   SQL_MUST( sqlite3_reset(ss_neigh) );
  33
  34   *np= head;
  35   return head;
  36 }
  37
  38
  39 static PotentialResult ***strat_base;
  40
  41
  42 static inline int isle2arch(int isle) {
  43   int arch= islandid2arch[isle];
  44   assert(arch>=0);
  45   return arch;
  46 }
  47
  48 static double process_route(int nports, int totaldist,
  49                             double overestimate_excepting_tail) {
  50   int i;
  51   int leagues_divisor= totaldist + nports;
  52
  53   ctr_routes_considered++;
  54
  55   debugf("========== ROUTE");
  56   for (i=0; i<nports; i++)
  57     debugf(" %d",ports[i]);
  58   debugf("\n");
  59
  60   int finisle= ports[nports-1]; int finarch= isle2arch(finisle);
  61   int midisle= ports[nports/2]; int midarch= isle2arch(midisle);
  62
  63   PotentialResult **strat_fin= ONDEMAND(strat_base[finarch], narches);
  64   PotentialResult *strat= ONDEMAND(strat_fin[midarch], 1);
  65
  66   if (nports>=2) {
  67     int pair[2], i;
  68     pair[1]= ports[nports-1];
  69     double guess_absolute= overestimate_excepting_tail;
  70
  71     for (i=0; i<nports; i++) {
  72       pair[0]= ports[i];
  73       IslandPair *ip= ipair_get_maybe(pair[0], pair[1]);
  74       if (!ip) continue;
  75       if (ip->route_tail_value < 0) {
  76         ctr_subroute_tails_valued++;
  77         ip->route_tail_value= value_route(2, pair, pair[0]!=pair[1]);
  78       }
  79       guess_absolute += ip->route_tail_value;
  80     }
  81     double guess_perleague= guess_absolute / leagues_divisor;
  82
  83     if (guess_absolute <= strat->absolute &&
  84         guess_perleague <= strat->perleague) {
  85       ctr_routes_eliminated++;
  86       debugf(" ELIM %f %f\n", guess_absolute, guess_perleague);
  87       return guess_absolute;
  88     }
  89     debugf(" COMPUTE %f %f\n", guess_absolute, guess_perleague);
  90   }
  91
  92   ctr_routes_valued++;
  93
  94   double absolute= value_route(nports, ports, 0);
  95   double perleague= absolute / leagues_divisor;
  96
  97   if (absolute <= strat->absolute &&
  98       perleague <= strat->perleague)
  99     return absolute;
 100
 101   debugf(" SOMEHOW BEST\n");
 102
 103   fildebugf("final %d:%3d mid %d:%3d ",finarch,finisle,midarch,midisle);
 104
 105 #define CHK(absperl)                                                    \
 106   fildebugf(#absperl " %15f", absperl);                                 \
 107   if (absperl < strat->absperl) {                                       \
 108     debugf("   ");                                                      \
 109   } else {                                                              \
 110     strat->absperl= absperl;                                            \
 111     memcpy(strat->absperl##_ports, ports, sizeof(*ports) * nports);     \
 112     fildebugf("** ");                                                   \
 113   }
 114
 115   CHK(absolute)
 116   CHK(perleague)
 117
 118   fildebugf(" route");
 119
 120   for (i=0; i<nports; i++)
 121     fildebugf(" %d",ports[i]);
 122   fildebugf("\n");
 123
 124   return absolute;
 125 }
 126
 127 static void recurse(int last_isle,
 128                     int nports, /* excluding last_isle */
 129                     int totaldist /* including last_isle */,
 130                     double last_estimate) {
 131   ports[nports++]= last_isle;
 132   double estimate= process_route(nports, totaldist, last_estimate);
 133   if (nports >= MAX_ROUTELEN) return;
 134
 135   Neighbour *add;
 136   for (add= get_neighbours(last_isle); add; add=add->next) {
 137     int newdist= totaldist + add->dist;
 138     if (newdist > max_dist) continue;
 139
 140     recurse(add->islandid, nports, newdist, estimate);
 141   }
 142 }
 143
 144 void search(int start_isle, PotentialResult ****strat_base_io) {
 145   strat_base= ONDEMAND(*strat_base_io, narches);
 146   recurse(start_isle,0,0,1e6);
 147 }
 148
 149
 150 int narches;
 151 char **archnames;
 152 int *islandid2arch;
 153
 154 void setup_search(void) {
 155   neighbours= mcalloc(sizeof(*neighbours) * islandtablesz);
 156
 157   SQL_PREPARE(ss_neigh,
 158               "SELECT biid, dist FROM routes WHERE aiid=?");
 159
 160   int max_narches=
 161     sql_single_int(" SELECT count(*) FROM (\n"
 162                    "  SELECT DISTINCT archipelago\n"
 163                    "   FROM islands\n"
 164                    "  )");
 165   archnames= mcalloc(sizeof(*archnames) * max_narches);
 166   islandid2arch= mmalloc(sizeof(*islandid2arch) * islandtablesz);
 167   int i;
 168   for (i=0; i<islandtablesz; i++) islandid2arch[i]=-1;
 169
 170   sqlite3_stmt *archs;
 171   SQL_PREPARE(archs,
 172               " SELECT islandid, archipelago\n"
 173               "  FROM islands\n"
 174               "  ORDER BY archipelago");
 175   while (SQL_STEP(archs)) {
 176     int isle= sqlite3_column_int(archs,0);
 177     const char *archname= (const char*)sqlite3_column_text(archs,1);
 178     int arch;
 179     for (arch=0; arch<narches; arch++)
 180       if (!strcmp(archnames[arch], archname)) goto found;
 181     assert(narches < max_narches);
 182     arch= narches++;
 183     archnames[arch]= masprintf("%s",archname);
 184   found:
 185     islandid2arch[isle]= arch;
 186   }
 187   sqlite3_finalize(archs);
 188 }