BUG: Fixed object type missmatch in SymLogNorm

Carwyn Pelley · pelson · commit e4b768c985c7 · 2013-10-08T09:07:30.000+01:00
Currently SymLogNorm accepts both linthresh and vmin, vmax with their
native dtype, meaning that the contents of one object cannot be updated
with another due to a mismatch of types.
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -1050,7 +1050,7 @@ def __init__(self,  linthresh, linscale=1.0,
         the logarithmic range. Defaults to 1.
         """
         Normalize.__init__(self, vmin, vmax, clip)
-        self.linthresh = linthresh
+        self.linthresh = float(linthresh)
         self._linscale_adj = (linscale / (1.0 - np.e ** -1))
 
     def __call__(self, value, clip=None):
@@ -1108,7 +1108,7 @@ def _transform_vmin_vmax(self):
         Calculates vmin and vmax in the transformed system.
         """
         vmin, vmax = self.vmin, self.vmax
-        arr = np.array([vmax, vmin])
+        arr = np.array([vmax, vmin]).astype(np.float)
         self._upper, self._lower = self._transform(arr)
 
     def inverse(self, value):
diff --git a/lib/matplotlib/tests/test_colors.py b/lib/matplotlib/tests/test_colors.py
@@ -72,6 +72,11 @@ def test_SymLogNorm():
     _scalar_tester(norm, vals)
     _mask_tester(norm, vals)
 
+    # Ensure that specifying vmin returns the same result as above
+    norm = mcolors.SymLogNorm(3, vmin=-30, vmax=5, linscale=1.2)
+    normed_vals = norm(vals)
+    assert_array_almost_equal(normed_vals, expected)
+
 
 def _inverse_tester(norm_instance, vals):
     """
