Merge pull request #337 from rasbt/float32

Allow lower precision array types in plot_decision_regions function

docs/sources/CHANGELOG.md

@@ -39,6 +39,7 @@ The CHANGELOG for the current development version is available at
 ##### Bug Fixes
 
 - Fixed issue when class labels were provided to the `EnsembleVoteClassifier` when `refit` was set to `false`. ([#322](https://github.com/rasbt/mlxtend/issues/322))
+- Allow arrays with 16-bit and 32-bit precision in `plot_decision_regions` function. ([#337](https://github.com/rasbt/mlxtend/issues/337))
 
 
 

mlxtend/plotting/decision_regions.py

@@ -201,7 +201,7 @@ def plot_decision_regions(X, y, clf,
         if dim > 2:
             for feature_idx in filler_feature_values:
                 X_predict[:, feature_idx] = filler_feature_values[feature_idx]
-    Z = clf.predict(X_predict)
+    Z = clf.predict(X_predict.astype(X.dtype))
     Z = Z.reshape(xx.shape)
     # Plot decisoin region
     ax.contourf(xx, yy, Z,

mlxtend/utils/checking.py

@@ -17,12 +17,12 @@ def check_Xy(X, y, y_int=True):
     if not isinstance(y, np.ndarray):
         raise ValueError('y must be a NumPy array. Found %s' % type(y))
 
-    if y_int and not np.issubdtype(y.dtype, np.integer):
+    if 'int' not in str(y.dtype):
         raise ValueError('y must be an integer array. Found %s. '
                          'Try passing the array as y.astype(np.integer)'
                          % y.dtype)
 
-    if X.dtype not in (np.float, np.int):
+    if not ('float' in str(X.dtype) or 'int' in str(X.dtype)):
         raise ValueError('X must be an integer or float array. Found %s.'
                          % X.dtype)
 

mlxtend/utils/tests/test_checking_inputs.py

@@ -29,6 +29,14 @@ def test_invalid_type_X():
                   y)
 
 
+def test_float16_X():
+    check_Xy(X.astype(np.float16), y)
+
+
+def test_float16_y():
+    check_Xy(X, y.astype(np.int16))
+
+
 def test_invalid_type_y():
     expect = "y must be a NumPy array. Found <class 'list'>"
     if (sys.version_info < (3, 0)):