[FIX] Classification models output correct shapes

Orange/base.py

@@ -320,6 +320,39 @@ def backmap_probs(self, probs, n_values, backmappers):
         new_probs = new_probs / tots[:, None]
         return new_probs
 
+    def data_to_model_domain(self, data: Table) -> Table:
+        """
+        Transforms data to the model domain if possible.
+
+        Parameters
+        ----------
+        data
+            Data to be transformed to the model domain
+
+        Returns
+        -------
+        Transformed data table
+
+        Raises
+        ------
+        DomainTransformationError
+            Error indicates that transformation is not possible since domains
+            are not compatible
+        """
+        if data.domain == self.domain:
+            return data
+
+        if self.original_domain.attributes != data.domain.attributes \
+                and data.X.size \
+                and not all_nan(data.X):
+            new_data = data.transform(self.original_domain)
+            if all_nan(new_data.X):
+                raise DomainTransformationError(
+                    "domain transformation produced no defined values")
+            return new_data.transform(self.domain)
+
+        return data.transform(self.domain)
+
     def __call__(self, data, ret=Value):
         multitarget = len(self.domain.class_vars) > 1
 
@@ -336,21 +369,6 @@ def one_hot_probs(value):
         def fix_dim(x):
             return x[0] if one_d else x
 
-        def data_to_model_domain():
-            if data.domain == self.domain:
-                return data
-
-            if self.original_domain.attributes != data.domain.attributes \
-                    and data.X.size \
-                    and not all_nan(data.X):
-                new_data = data.transform(self.original_domain)
-                if all_nan(new_data.X):
-                    raise DomainTransformationError(
-                        "domain transformation produced no defined values")
-                return new_data.transform(self.domain)
-
-            return data.transform(self.domain)
-
         if not 0 <= ret <= 2:
             raise ValueError("invalid value of argument 'ret'")
         if ret > 0 and any(v.is_continuous for v in self.domain.class_vars):
@@ -368,14 +386,18 @@ def data_to_model_domain():
         else:
             one_d = False
 
+        # if sparse convert to csr_matrix
+        if scipy.sparse.issparse(data):
+            data = data.tocsr()
+
         # Call the predictor
         backmappers = None
         n_values = []
         if isinstance(data, (np.ndarray, scipy.sparse.csr.csr_matrix)):
             prediction = self.predict(data)
         elif isinstance(data, Table):
             backmappers, n_values = self.get_backmappers(data)
-            data = data_to_model_domain()
+            data = self.data_to_model_domain(data)
             prediction = self.predict_storage(data)
         elif isinstance(data, (list, tuple)):
             data = Table.from_list(self.original_domain, data)

Orange/classification/svm.py

@@ -8,13 +8,8 @@
 svm_pps = SklLearner.preprocessors + [AdaptiveNormalize()]
 
 
-class SVMClassifier(SklModel):
-    pass
-
-
 class SVMLearner(SklLearner):
     __wraps__ = skl_svm.SVC
-    __returns__ = SVMClassifier
     preprocessors = svm_pps
 
     def __init__(self, C=1.0, kernel='rbf', degree=3, gamma="auto",

Orange/classification/tests/test_base.py

@@ -186,6 +186,17 @@ def test_no_common_values(self):
             self.assertTrue(np.all(val <= 2))
             np.testing.assert_array_equal(prob, 1 / 3)
 
+    def test_sparse_matrix(self):
+        iris_sparse = self.iris.to_sparse()
+        for lrn in [LogisticRegressionLearner, TreeLearner]:  # skl and non-skl
+            model = lrn()(iris_sparse)
+            pred = model(iris_sparse.X.tocsc())
+            self.assertTupleEqual((len(self.iris),), pred.shape)
+            pred = model(iris_sparse.X.tolil())
+            self.assertTupleEqual((len(self.iris),), pred.shape)
+            pred = model(iris_sparse.X.tocoo())
+            self.assertTupleEqual((len(self.iris),), pred.shape)
+
 
 if __name__ == '__main__':
     unittest.main()

Orange/tests/test_classification.py

@@ -24,7 +24,7 @@
     SimpleRandomForestLearner, EllipticEnvelopeLearner)
 from Orange.classification.rules import _RuleLearner
 from Orange.data import (ContinuousVariable, DiscreteVariable,
-                         Domain, Table, Variable)
+                         Domain, Table)
 from Orange.data.table import DomainTransformationError
 from Orange.evaluation import CrossValidation
 from Orange.tests.dummy_learners import DummyLearner, DummyMulticlassLearner