Add a new class for Absolute Bias involving the function

ocw/metrics.py

@@ -89,6 +89,28 @@ def run(self, ref_dataset, target_dataset):
         :rtype: :class:`numpy.ndarray`
         '''
         return calc_bias(target_dataset.values, ref_dataset.values)
+
+
+class AbsoluteBias(BinaryMetric):
+    '''Calculate the absolute bias between a reference and target dataset.'''
+
+    def run(self, ref_dataset, target_dataset):
+        '''Calculate the absolute bias between a reference and target dataset.
+
+        .. note::
+           Overrides BinaryMetric.run()
+
+        :param ref_dataset: The reference dataset to use in this metric run.
+        :type ref_dataset: :class:`dataset.Dataset`
+
+        :param target_dataset: The target dataset to evaluate against the
+            reference dataset in this metric run.
+        :type target_dataset: :class:`dataset.Dataset`
+
+        :returns: The absolute difference between the reference and target datasets.
+        :rtype: :class:`numpy.ndarray`
+        '''
+        return calc_absbias(target_dataset.values, ref_dataset.values)
 
 
 class SpatialPatternTaylorDiagram(BinaryMetric):