2 files changed, 16 insertions, 13 deletions
diff --git a/Wrappers/Python/ccpi/processors/CenterOfRotationFinder.py b/Wrappers/Python/ccpi/processors/CenterOfRotationFinder.py
index 11b640f..f9ed19d 100755
--- a/Wrappers/Python/ccpi/processors/CenterOfRotationFinder.py
+++ b/Wrappers/Python/ccpi/processors/CenterOfRotationFinder.py
@@ -43,9 +43,9 @@ class CenterOfRotationFinder(DataProcessor):
         #DataProcessor.__init__(self, **kwargs)
         super(CenterOfRotationFinder, self).__init__(**kwargs)
         
-    def set_slice(self, slice):
+    def set_slice(self, slice_index='centre'):
         """
-        Set the slice to run over in a 3D data set.
+        Set the slice to run over in a 3D data set. The default will use the centre slice.
 
         Input is any valid slice index or 'centre'
         """
@@ -53,21 +53,21 @@ class CenterOfRotationFinder(DataProcessor):
 
         if dataset is None:
             raise ValueError('Please set input data before slice selection')    
+        
+        if dataset.number_of_dimensions == 2:
+            print('Slice number not a valid parameter of a 2D data set')
 
         #check slice number is valid
-        if dataset.number_of_dimensions == 3:
-            if slice == 'centre':
-                slice = dataset.get_dimension_size('vertical')//2 
-
-            elif slice >= dataset.get_dimension_size('vertical'):
+        elif dataset.number_of_dimensions == 3:
+            if slice_index == 'centre':
+                slice_index = dataset.get_dimension_size('vertical')//2 
+            elif not isinstance(slice_index, (int)):
+                raise TypeError("Invalid input. Expect integer slice index.")               
+            elif slice_index >= dataset.get_dimension_size('vertical'):
                 raise ValueError("Slice out of range must be less than {0}"\
                     .format(dataset.get_dimension_size('vertical')))
 
-        elif dataset.number_of_dimensions == 2:
-            if slice is not None:
-                raise ValueError('Slice number not a valid parameter of a 2D data set')
-
-        self.slice_number = slice
+            self.slice_number = slice_index
 
     def check_input(self, dataset):
         #check dataset
diff --git a/Wrappers/Python/test/test_DataProcessor.py b/Wrappers/Python/test/test_DataProcessor.py
index 55f38d3..1666ea8 100755
--- a/Wrappers/Python/test/test_DataProcessor.py
+++ b/Wrappers/Python/test/test_DataProcessor.py
@@ -64,7 +64,7 @@ class TestDataProcessor(unittest.TestCase):
         print ("Center of rotation", cf.get_output())
         self.assertAlmostEqual(86.25, cf.get_output())
 
-    #def test_CenterOfRotation_slice(self):
+    #def test_CenterOfRotation_singleslice(self):
         #reader = NexusReader(self.filename)
         #data = reader.get_acquisition_data_whole()
         
@@ -87,6 +87,9 @@ class TestDataProcessor(unittest.TestCase):
         cf.set_slice(80)
         print ("Center of rotation", cf.get_output())
         self.assertAlmostEqual(86.25, cf.get_output())
+        cf.set_slice()
+        print ("Center of rotation", cf.get_output())
+        self.assertAlmostEqual(86.25, cf.get_output())       
         cf.set_slice('centre')
         print ("Center of rotation", cf.get_output())
         self.assertAlmostEqual(86.25, cf.get_output())