Merge pull request #92 from jvkersch/fix-random-seed

fix: correct inverted random seed logic in _CCtsp_solve_dat

Author: jvkersch

concorde/_concorde.pyx

@@ -106,7 +106,7 @@ def _CCtsp_solve_dat(
 
     out_tour = np.zeros(ncount, dtype=np.int32)
 
-    if seed != 0:
+    if seed == 0:
         seed = <int>CCutil_real_zeit()
     CCutil_sprand (seed, &rstate)
 

concorde/tests/data_utils.py

@@ -1,6 +1,7 @@
 from os.path import dirname, join as pjoin
 
 import numpy as np
+import numpy.testing as nptest
 
 
 BERLIN_TOUR = np.array(
@@ -72,3 +73,17 @@ def get_dataset_path(tspname):
 
 def get_solution_data(tspname):
     return SOLUTION_DATA[tspname]
+
+
+def assert_tour_equal(actual, expected):
+    """Assert two TSP tours are equal, allowing for reverse direction.
+
+    A TSP tour is a cycle, so the same optimal tour starting at node 0
+    can be traversed in either direction.
+    """
+    try:
+        nptest.assert_array_equal(actual, expected)
+    except AssertionError:
+        # Try reversed direction: keep node 0 first, reverse the rest
+        reversed_tour = np.concatenate([[expected[0]], expected[1:][::-1]])
+        nptest.assert_array_equal(actual, reversed_tour)

concorde/tests/test_concorde_core.py

@@ -5,7 +5,7 @@
 import numpy.testing as nptest
 
 from concorde._concorde import _CCutil_gettsplib, _CCtsp_solve_dat
-from concorde.tests.data_utils import get_dataset_path, get_solution_data
+from concorde.tests.data_utils import get_dataset_path, get_solution_data, assert_tour_equal
 
 
 class TestCCutil_gettsplib(unittest.TestCase):
@@ -45,7 +45,7 @@ def test_solve_berlin_normal(self):
         )
 
         # Then
-        nptest.assert_array_equal(tour, expected_tour)
+        assert_tour_equal(tour, expected_tour)
         self.assertAlmostEqual(val, expected_opt_value)
         self.assertTrue(success)
         self.assertTrue(foundtour)

concorde/tests/test_concorde_datagroup.py

@@ -4,7 +4,7 @@
 import numpy.testing as nptest
 
 from concorde.tsp import TSPSolver
-from concorde.tests.data_utils import get_dataset_path, get_solution_data
+from concorde.tests.data_utils import get_dataset_path, get_solution_data, assert_tour_equal
 
 
 class TestTSPSolver(unittest.TestCase):
@@ -75,7 +75,7 @@ def test_solve(self):
         tour, val, success, foundtour, hit_timebound = datagroup.solve()
 
         # Then
-        nptest.assert_array_equal(tour, expected_tour)
+        assert_tour_equal(tour, expected_tour)
         self.assertAlmostEqual(val, expected_opt_value)
         self.assertTrue(success)
         self.assertTrue(foundtour)