relax DSO solver route search

Author: toruseo

uxsim/DTAsolvers/DTAsolvers.py

@@ -416,7 +416,7 @@ def solve(s, max_iter, n_routes_per_od=4, beta_coef=100, beta_coef2=5000, print_
                     break
 
                 tmp_counter += 1
-                if tmp_counter>10000:
+                if tmp_counter > 1000000:
                     raise Exception("DSO error: No alternative routes.")
 
             routes_specified = {}