Specify stat uncertainty only once per stack

nnfwtbn/plot.py

@@ -235,6 +235,9 @@ def hist(dataframe, variable, bins, stacks, selection=None,
             uncertainty = stack.get_total_uncertainty(c_blind(dataframe),
                                                       bins, variable,
                                                       weight, False)
+            if i_process != 0:
+                # We want to add the uncertainty only once!
+                uncertainty *= 0
             uncertainty = uncertainty / density_norm
 
 

nnfwtbn/tests/test_hist.py

+
+import unittest
+import pandas as pd
+import nnfwtbn
+
+class HistTestBase(unittest.TestCase):
+    """
+    Test the implementation of hist().
+
+    The implementation is tested by inspecting the returned uhepp objects.
+    """
+
+    def setUp(self):
+        """Set up a toy dataframe and processes"""
+        self.data = pd.DataFrame({
+            "m": [10, 10, 10, 10, 10],
+            "w": [ 1,  2,  1,  3,  8],
+            "p": [ 1,  1,  1,  2,  3]
+        })
+
+        self.process_a = nnfwtbn.Process("a", lambda d: d.p == 1)
+        self.process_b = nnfwtbn.Process("b", lambda d: d.p == 2)
+        self.mc_stack = nnfwtbn.McStack(self.process_a, self.process_b)
+
+        self.process_x = nnfwtbn.Process("x", lambda d: d.p == 3)
+        self.data_stack = nnfwtbn.McStack(self.process_x)
+
+    def test_yield_base(self):
+        """Check the bin contents"""
+        hist = nnfwtbn.hist(self.data, variable="m", weight="w", bins=[0, 20],
+                            stacks=[self.mc_stack, self.data_stack],
+                            return_uhepp=True)
+        
+        self.assertEqual(hist.yields["s0_p0"].base, [0, 4, 0])
+        self.assertEqual(hist.yields["s0_p1"].base, [0, 3, 0])
+        self.assertEqual(hist.yields["s1_p0"].base, [0, 8, 0])
+
+    def test_yiele_stat(self):
+        """Check the statistical uncertainties"""
+        hist = nnfwtbn.hist(self.data, variable="m", weight="w", bins=[0, 20],
+                            stacks=[self.mc_stack, self.data_stack],
+                            return_uhepp=True)
+        
+        self.assertAlmostEqual(hist.yields["s0_p0"].stat[1]**2, 15)
+        self.assertAlmostEqual(hist.yields["s0_p1"].stat[1]**2,  0)
+        self.assertAlmostEqual(hist.yields["s1_p0"].stat[1]**2, 64)