split up stdout heading output line printing (no functional change)

[matchsticks-search.git] / main.c

diff --git a/main.c b/main.c
index 57a979654f705bd01912fe773cd01668a92ddb07..08bf5cb6ff524caf3fc84a62fc5e113bdc5d86f9 100644 (file)
--- a/main.c
+++ b/main.c
@@ -5,7 +5,13 @@
  *
  * Invoke as   ./main n m
  *
- * The algorithm is faster if the arguments are ordered so that n > m.
+ * The arguments must be ordered so that n > m:
+ *   n is the number of (more, shorter) input matches of length m
+ *   m is the number of (fewer, longer) output matches of length n
+ *
+ * Options:
+ *  -j<jobs>     run in parallel on <jobs> cores
+ *  -b<best>     search only for better than <best>
  */
 
 /*
@@ -84,7 +90,10 @@
  *
  * We further winnow the set of possible adjacency matrices, by
  * ensuring the same bit is not set in too many entries of adjmatrix
- * (ie, as above, only considering output sticks).
+ * (ie, as above, only considering output sticks); and by ensuring
+ * that it is not set in too few: each output stick must consist
+ * of at least two fragments since the output sticks are longer than
+ * the input ones.
  *
  * And, we want to do the search in order of increasing maximum
  * hamming weight.  This is because in practice optimal solutions tend
@@ -133,9 +142,13 @@ static void set_best(double new_best) {
    *   <=>       frags <   |  n / best  |
    *                        _          _
    *   <=>       frags <=  |  n / best  | - 1
+   *
+   * But best values from glpk are slightly approximate, so we
+   * subtract a fudge factor from our target.
    */
-  n_max_frags = ceil(n / best) - 1;
-  m_max_frags = ceil(m / best) - 1;
+  double near_best = best * 0.98 - 0.02;
+  n_max_frags = ceil(n / near_best) - 1;
+  m_max_frags = ceil(m / near_best) - 1;
 }
 
 /*----- multicore support -----*/
@@ -623,6 +636,10 @@ static void iterate_recurse(int i, AdjWord min) {
   AdjWord jbit;
 
   if (i >= n) {
+    for (j=0; j<m; j++)
+      if (weight[j] < 2)
+       return;
+
     printcounter++;
     optimise(!(printcounter & 0xfff));
     return;
@@ -670,6 +687,13 @@ static void iterate(void) {
 
 static void report(void) {
   fprintf(stderr, "\n");
+  if (best_adjmatrix) {
+    int i;
+    fprintf(stderr,"  ");
+    for (i=0; i<n; i++) fprintf(stderr, " %"PRADJ, best_adjmatrix[i]);
+    fprintf(stderr," OK\n");
+  }
+  printf("%d into %d: ", n, m);
   if (best_prob) {
     double min = glp_get_obj_val(best_prob);
     double a[n][m];
@@ -684,7 +708,7 @@ static void report(void) {
         continue;
       a[x][y] = min + glp_get_col_prim(best_prob, i);
     }
-    printf("%d into %d: min fragment %g   [%s]\n", n, m, min, VERSION);
+    printf("min fragment %g", min);
     for (i = 0; i < n; i++) {
       for (j = 0; j < m; j++) {
         if (a[i][j])
@@ -695,6 +719,7 @@ static void report(void) {
       printf("\n");
     }
   }
+  printf("   [%s]\n", VERSION);
   if (ferror(stdout) || fclose(stdout)) { perror("stdout"); exit(-1); }
 }
  
@@ -703,6 +728,7 @@ int main(int argc, char **argv) {
   while ((opt = getopt(argc,argv,"j:")) >= 0) {
     switch (opt) {
     case 'j': ncpus = atoi(optarg); break;
+    case 'b': set_best(atof(optarg)); break;
     case '+': assert(!"bad option");
     default: abort();
     }
@@ -712,6 +738,7 @@ int main(int argc, char **argv) {
   assert(argc==3);
   n = atoi(argv[1]);
   m = atoi(argv[2]);
+  assert(n > m);
 
   prep();