Merge pull request #25405 from haval0/issue/24092

jklymak · web-flow · commit 9e52bc821574 · 2023-03-28T13:41:29.000-07:00
Fix incorrect stride calculations in LogLocator.tick_values()
diff --git a/lib/matplotlib/tests/test_ticker.py b/lib/matplotlib/tests/test_ticker.py
@@ -239,6 +239,26 @@ def test_set_params(self):
         assert loc._base == 4
         assert list(loc._subs) == [2.0]
 
+    def test_tick_values_correct(self):
+        ll = mticker.LogLocator(subs=(1, 2, 5))
+        test_value = np.array([1.e-01, 2.e-01, 5.e-01, 1.e+00, 2.e+00, 5.e+00,
+                               1.e+01, 2.e+01, 5.e+01, 1.e+02, 2.e+02, 5.e+02,
+                               1.e+03, 2.e+03, 5.e+03, 1.e+04, 2.e+04, 5.e+04,
+                               1.e+05, 2.e+05, 5.e+05, 1.e+06, 2.e+06, 5.e+06,
+                               1.e+07, 2.e+07, 5.e+07, 1.e+08, 2.e+08, 5.e+08])
+        assert_almost_equal(ll.tick_values(1, 1e7), test_value)
+
+    def test_tick_values_not_empty(self):
+        mpl.rcParams['_internal.classic_mode'] = False
+        ll = mticker.LogLocator(subs=(1, 2, 5))
+        test_value = np.array([1.e-01, 2.e-01, 5.e-01, 1.e+00, 2.e+00, 5.e+00,
+                               1.e+01, 2.e+01, 5.e+01, 1.e+02, 2.e+02, 5.e+02,
+                               1.e+03, 2.e+03, 5.e+03, 1.e+04, 2.e+04, 5.e+04,
+                               1.e+05, 2.e+05, 5.e+05, 1.e+06, 2.e+06, 5.e+06,
+                               1.e+07, 2.e+07, 5.e+07, 1.e+08, 2.e+08, 5.e+08,
+                               1.e+09, 2.e+09, 5.e+09])
+        assert_almost_equal(ll.tick_values(1, 1e8), test_value)
+
 
 class TestNullLocator:
     def test_set_params(self):
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -2336,7 +2336,7 @@ def tick_values(self, vmin, vmax):
         # Get decades between major ticks.
         stride = (max(math.ceil(numdec / (numticks - 1)), 1)
                   if mpl.rcParams['_internal.classic_mode'] else
-                  (numdec + 1) // numticks + 1)
+                  numdec // numticks + 1)
 
         # if we have decided that the stride is as big or bigger than
         # the range, clip the stride back to the available range - 1
