pass weight array to workers (fix semantic conflict between horizontal weight elimina...

[matchsticks-search.git] / main.c

diff --git a/main.c b/main.c
index 5eb9e19d6b0b7caa3324e9c515561b895639a14e..b02e98cbda4beae56f0592e10997bc7ef854ed6e 100644 (file)
--- a/main.c
+++ b/main.c
@@ -34,6 +34,7 @@
 #include <unistd.h>
 #include <stdbool.h>
 #include <inttypes.h>
+#include <math.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/uio.h>
@@ -94,6 +95,9 @@ static double best;
 static glp_prob *best_prob;
 static AdjWord *best_adjmatrix;
 
+static int n_over_best;
+static int *weight;
+
 static unsigned printcounter;
 
 static void iterate(void);
@@ -107,6 +111,11 @@ static void progress_eol(void) {
   fflush(stderr);
 }
 
+static void set_best(double new_best) {
+  best = new_best;
+  n_over_best = floor(n / best);
+}
+
 /*----- multicore support -----*/
 
 /*
@@ -149,7 +158,7 @@ static Worker *mc_us;
 
 static void multicore_check_for_new_best(void);
 
-#define MAX_NIOVS 3
+#define MAX_NIOVS 4
 static AdjWord mc_iter_min;
 static int mc_niovs;
 static size_t mc_iovlen;
@@ -170,6 +179,7 @@ static void mc_rwvsetup_outer(void) {
   IOV(maxhamweight, 1);
   IOV(mc_iter_min, 1);
   IOV(*adjmatrix, multicore_iteration_boundary);
+  IOV(*weight, m);
 }
 
 static void mc_rwvsetup_full(void) {
@@ -202,6 +212,8 @@ static void mc_awaitpid(int wnum, pid_t pid) {
 }
 
 static void multicore_outer_iteration(int i, AdjWord min) {
+  static unsigned check_counter;
+
   assert(i == multicore_iteration_boundary);
   mc_iter_min = min;
   mc_rwvsetup_outer();
@@ -209,6 +221,9 @@ static void multicore_outer_iteration(int i, AdjWord min) {
   assert(r == mc_iovlen);
   /* effectively, this writev arranges to transfers control
    * to some worker's instance of iterate_recurse via mc_iterate_worker */
+
+  if (!(check_counter++ & 0xff))
+    multicore_check_for_new_best();
 }
 
 static void mc_iterate_worker(void) {
@@ -304,7 +319,7 @@ static void multicore_check_for_new_best(void) {
     if (!got) break;
     assert(got == sizeof(msg));
     if (msg > best)
-      best = msg;
+      set_best(msg);
     mc_bus_read += sizeof(msg);
   }
 }
@@ -328,6 +343,8 @@ static void prep(void) {
   adjmatrix = xalloc_adjmatrix();
   glp_term_out(GLP_OFF);
   setlinebuf(stderr);
+  weight = calloc(sizeof(*weight), m);  assert(weight);
+  n_over_best = INT_MAX;
 }
 
 static AdjWord one_adj_bit(int bitnum) {
@@ -550,7 +567,7 @@ static void optimise(bool doprint) {
 
   HAVE_PRINTED;
 
-  best = got;
+  set_best(got);
   multicore_found_new_best();
 
   if (best_prob) glp_delete_prob(best_prob);
@@ -589,8 +606,20 @@ static void iterate_recurse(int i, AdjWord min) {
     if (i == 0 && (adjmatrix[i] & (1+adjmatrix[i])))
       goto again;
 
+    for (int j = 0; j < m; j++)
+      if (adjmatrix[i] & one_adj_bit(j))
+        weight[j]++;
+    for (int j = 0; j < m; j++)
+      if (weight[j] >= n_over_best)
+        goto takeout;
+
     iterate_recurse(i+1, adjmatrix[i]);
 
+  takeout:
+    for (int j = 0; j < m; j++)
+      if (adjmatrix[i] & one_adj_bit(j))
+        weight[j]--;
+
   again:
     if (adjmatrix[i] == adjall)
       return;