fix(model): begin interval audit at start of data collection period (rather than start of warm-up period) (plus re-run notebooks)

Author: amyheather

notebooks/analysis.ipynb

@@ -521,6 +521,7 @@ def attend_clinic(self, patient):
     def interval_audit(self, interval):
         """
         Audit waiting times and resource utilisation at regular intervals.
+        This is set-up to start when the warm-up period has ended.
 
         The running mean wait time is calculated using Welford's Running
         Average, which is a method that avoids the need to store previous wait
@@ -531,6 +532,10 @@ def interval_audit(self, interval):
             interval (int, optional):
                 Time between audits in minutes.
         """
+        # Wait until warm-up period has passed
+        yield self.env.timeout(self.param.warm_up_period)
+
+        # Begin interval auditor
         while True:
             self.audit_list.append({
                 'resource_name': 'nurse',

notebooks/choosing_parameters.ipynb

@@ -221,15 +221,17 @@ def helper_warmup(warm_up_period):
     )
 
     # Check that the first interval audit entry with no warm-up has time and
-    # results of 0
+    # no queue or wait time. However, as our first patient arrives at time 0,
+    # we do expect to have utilisation over 0.
     first_interval = results_none['interval_audit'].iloc[0]
     assert first_interval['simulation_time'] == 0, (
         'With no warm-up, expect first entry in interval audit to be ' +
         f'at time 0, but it was at time {first_interval['simulation_time']}.'
     )
-    assert first_interval['utilisation'] == 0, (
+    assert first_interval['utilisation'] > 0, (
         'With no warm-up, expect first entry in interval audit to ' +
-        f'have 0 utilisation, but it was {first_interval['utilisation']}.'
+        'have utilisation greater than 0 (as first patient arrives at time ' +
+        f'0), but utilisation was {first_interval['utilisation']}.'
     )
     assert first_interval['queue_length'] == 0, (
         'With no warm-up, expect first entry in interval audit to ' +
@@ -242,6 +244,16 @@ def helper_warmup(warm_up_period):
         f'{first_interval['running_mean_wait_time']}.'
     )
 
+    # Check that first interval audit entry with a warm-up has time 500
+    # (matching length of warm-up period) - and so ensuring the first entry
+    # in the interval audit, which occurs at the end of the warm-up period,
+    # has not been deleted.
+    first_interval_warmup = results_warmup['interval_audit'].iloc[0]
+    assert first_interval_warmup['simulation_time'] == 500, (
+        'With warm-up of 500, expect first entry in interval audit to be ' +
+        f'at time 500, but it was at time {first_interval['simulation_time']}.'
+    )
+
 
 def test_arrivals():
     """