From: Martin Mares <mj@ucw.cz>
Date: Sun, 27 Mar 2022 12:48:49 +0000 (+0200)
Subject: Průvodce: Bi-directional Dijkstra balanced by distance
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=cd9c147b5a119854f441ab04651f402adb75c3d5;p=leo.git

Průvodce: Bi-directional Dijkstra balanced by distance
---

diff --git a/graph.c b/graph.c
index 47b4b3d..b7efc87 100644
--- a/graph.c
+++ b/graph.c
@@ -18,7 +18,7 @@
 #include "map.h"
 #include "graph.h"
 
-static uint bidir;
+static uint bidir;	// 0=unidir, 1=bidir balanced by #opened, 2=bidir balanced by distance
 static uint astar;
 
 static struct cf_section graph_cf = {
@@ -256,13 +256,18 @@ static void bidir_dijkstra(struct graph_vertex *v_src, struct graph_vertex *v_de
   v_dest->state[1] = 1;
   v_dest->dist[1] = 0;
 
-  uint open[2] = { 1, 1 };
+  uint opened[2] = { 1, 1 }, closed[2] = { 0, 0 };
+  double last_dist[2] = { 0, 0 };
   struct graph_vertex *w;
 
   for (;;)
     {
       double best_d = 0;
-      uint dir = (open[0] <= open[1]) ? 0 : 1;
+      uint dir;
+      if (bidir == 2)
+	dir = (last_dist[0] <= last_dist[1]) ? 0 : 1;
+      else
+	dir = (opened[0] <= opened[1]) ? 0 : 1;
       w = NULL;
       // msg(L_DEBUG, "Dijkstra: dir=%d", dir);
 
@@ -282,6 +287,8 @@ static void bidir_dijkstra(struct graph_vertex *v_src, struct graph_vertex *v_de
 	die("Path not found");
 
       // msg(L_DEBUG, "Dijkstra: closing vertex #%jd (d=%f, dir %d)", w->node->o.id, best_d, dir);
+      closed[dir]++;
+      last_dist[dir] = best_d;
 
       w->state[dir] = 2;
       if (w->state[!dir] == 2)
@@ -299,7 +306,7 @@ static void bidir_dijkstra(struct graph_vertex *v_src, struct graph_vertex *v_de
 	      x->state[dir] = 1;
 	      x->dist[dir] = d;
 	      x->via_edge[dir] = e;
-	      open[dir]++;
+	      opened[dir]++;
 	    }
 	}
     }
@@ -333,6 +340,7 @@ static void bidir_dijkstra(struct graph_vertex *v_src, struct graph_vertex *v_de
       w = ev;
     }
 
+  msg(L_DEBUG, "Dijkstra: Stats: %u/%u opened, %u/%u closed", opened[0], opened[1], closed[0], closed[1]);
   visualize_states(v_src, v_dest);
   visualize_path(w, 0);
   visualize_path(w, 1);
@@ -345,10 +353,13 @@ static void dijkstra(struct graph_vertex *v_src, struct graph_vertex *v_dest)
   v_src->state[0] = 1;
   v_src->dist[0] = 0;
 
+  uint opened = 1, closed = 0;
+  struct graph_vertex *w;
+
   for (;;)
     {
-      struct graph_vertex *w = NULL;
       double best_d = 0;
+      w = NULL;
 
       CLIST_FOR_EACH(struct graph_vertex *, v, graph_vertices)
 	if (v->state[0] == 1)
@@ -364,14 +375,10 @@ static void dijkstra(struct graph_vertex *v_src, struct graph_vertex *v_dest)
 	die("Path not found");
 
       // msg(L_DEBUG, "Dijkstra: closing vertex #%jd", w->node->o.id);
+      closed++;
 
       if (w == v_dest)
-	{
-	  msg(L_INFO, "Found path: dist=%f", w->dist[0]);
-	  visualize_states(v_src, v_dest);
-	  visualize_path(v_dest, 0);
-	  return;
-	}
+	break;
 
       w->state[0] = 2;
       CLIST_FOR_EACH(struct graph_edge *, e, w->edges)
@@ -386,9 +393,15 @@ static void dijkstra(struct graph_vertex *v_src, struct graph_vertex *v_dest)
 	      x->state[0] = 1;
 	      x->dist[0] = d;
 	      x->via_edge[0] = e;
+	      opened++;
 	    }
 	}
     }
+
+  msg(L_INFO, "Dijkstra: Found path: dist=%f", w->dist[0]);
+  msg(L_INFO, "Dijkstra: Stats: %u opened, %u closed", opened, closed);
+  visualize_states(v_src, v_dest);
+  visualize_path(v_dest, 0);
 }
 
 void graph_build(void)
diff --git a/mk-all b/mk-all
index 82cde3a..3c57720 100755
--- a/mk-all
+++ b/mk-all
@@ -2,7 +2,7 @@
 set -e
 make
 for a in 0 1 ; do
-	for b in 0 1 ; do
+	for b in 0 1 2 ; do
 		out="output"
 		case $a in
 			0)	out="$out-dijk" ;;
@@ -12,6 +12,7 @@ for a in 0 1 ; do
 		case $b in
 			0)	out="$out-unidir" ;;
 			1)	out="$out-bidir" ;;
+			2)	out="$out-bidir2" ;;
 			*)	exit 1 ;;
 		esac
 		echo "### Running with astar=$a bidir=$b ($out) ###"