#23 Add distortion calculator

Author: pockerman

src/utils/distortion_calculator.py

@@ -0,0 +1,51 @@
+"""
+Utilities for dataset distortion calculation
+"""
+import enum
+from typing import TypeVar
+from src.utils.numeric_distance_type import NumericDistanceType
+from src.utils.numeric_distance_calculator import NumericDistanceCalculator
+from src.utils.string_distance_calculator import StringDistanceType, TextDistanceCalculator
+from src.exceptions.exceptions import InvalidParamValue
+
+Vector = TypeVar('Vector')
+
+
+class DistortionCalculationType(enum.IntEnum):
+    """
+
+    """
+
+    INVALID = -1
+    SUM = 0
+    AVG = 1
+
+
+class DistortionCalculator(object):
+
+    def __init__(self, numeric_column_distortion_metric_type: NumericDistanceType,
+                 string_column_distortion_metric_type: StringDistanceType,
+                 dataset_distortion_type: DistortionCalculationType):
+        self.numeric_column_distortion_metric_type = numeric_column_distortion_metric_type
+        self.string_column_distortion_metric_type = string_column_distortion_metric_type
+        self.dataset_distortion_type = dataset_distortion_type
+
+    def calculate(self, vec1: Vector, vec2: Vector, datatype: str) -> float:
+
+        if datatype == 'str':
+            return TextDistanceCalculator(dist_type=self.string_column_distortion_metric_type).calculate(txt1=vec1,
+                                                                                                         txt2=vec2)
+        elif datatype == 'float' or datatype == 'int':
+            return NumericDistanceCalculator(dist_type=self.numeric_column_distortion_metric_type).calculate(state1=vec1,
+                                                                                                             state2=vec2)
+        raise InvalidParamValue(param_name='datatype', param_value=datatype)
+
+    def total_distortion(self, distortions: Vector) -> float:
+
+        if self.dataset_distortion_type == DistortionCalculationType.SUM:
+            return float(sum(distortions))
+        elif self.dataset_distortion_type == DistortionCalculationType.AVG:
+            return float(sum(distortions) / len(distortions))
+
+        raise InvalidParamValue(param_name='dataset_distortion_type', param_value=self.dataset_distortion_type.name)
+