Make get_instance_features return np.ndarray

miplearn/instance/base.py

@@ -6,6 +6,8 @@ import logging
 from abc import ABC, abstractmethod
 from typing import Any, List, TYPE_CHECKING, Dict
 
+import numpy as np
+
 from miplearn.features.sample import Sample, MemorySample
 
 logger = logging.getLogger(__name__)
@@ -37,7 +39,7 @@ class Instance(ABC):
         """
         pass
 
-    def get_instance_features(self) -> List[float]:
+    def get_instance_features(self) -> np.ndarray:
         """
         Returns a 1-dimensional array of (numerical) features describing the
         entire instance.
@@ -59,7 +61,7 @@ class Instance(ABC):
 
         By default, returns [0.0].
         """
-        return [0.0]
+        return np.zeros(1)
 
     def get_variable_features(self) -> Dict[str, List[float]]:
         """

miplearn/instance/file.py

@@ -6,6 +6,7 @@ import os
 from typing import Any, Optional, List, Dict, TYPE_CHECKING
 import pickle
 
+import numpy as np
 from overrides import overrides
 
 from miplearn.features.sample import Hdf5Sample, Sample
@@ -30,7 +31,7 @@ class FileInstance(Instance):
         return self.instance.to_model()
 
     @overrides
-    def get_instance_features(self) -> List[float]:
+    def get_instance_features(self) -> np.ndarray:
         assert self.instance is not None
         return self.instance.get_instance_features()
 

miplearn/instance/picklegz.py

@@ -8,6 +8,7 @@ import os
 import pickle
 from typing import Optional, Any, List, cast, IO, TYPE_CHECKING, Dict
 
+import numpy as np
 from overrides import overrides
 
 from miplearn.features.sample import Sample
@@ -42,7 +43,7 @@ class PickleGzInstance(Instance):
         return self.instance.to_model()
 
     @overrides
-    def get_instance_features(self) -> List[float]:
+    def get_instance_features(self) -> np.ndarray:
         assert self.instance is not None
         return self.instance.get_instance_features()