Bug fix: traverse the graph in chronological order

So that segments in a trajectory are in chronological order.

gt_matlab_trajs.py

@@ -18,9 +18,16 @@ import graph_tool
 from os import path
 import json
 import csv
-from graph_tool import util
+from graph_tool import util, search
 import sys
 
+class Visitor(search.BFSVisitor):
+    def discover_vertex(self, u):
+        if g.vp.traj[u] not in trajectories:
+            trajectories[g.vp.traj[u]] = [g.vp.name[u]]
+        else:
+            trajectories[g.vp.traj[u]].append(g.vp.name[u])
+
 g = graph_tool.load_graph(sys.argv[1])
 g.vp['traj'] = g.new_vp('int')
 
@@ -59,12 +66,7 @@ print('Algorithm done, saving...')
 # Make a dictionary of trajectories:
 
 trajectories = {}
-
-for node in g.vertices():
-    if g.vp.traj[node] not in trajectories:
-        trajectories[g.vp.traj[node]] = [g.vp.name[node]]
-    else:
-        trajectories[g.vp.traj[node]].append(g.vp.name[node])
+search.bfs_search(g, visitor = Visitor())
 
 with open("trajectories.json", "w") as outfile:
     json.dump(trajectories, outfile, indent = 4)