Update Pollen.com to use numpy for trend analysis (#18107)

* Update Pollen.com to use numpy for trend analysis

* Hound

* Linting

homeassistant/components/sensor/pollen.py

@@ -18,7 +18,7 @@ from homeassistant.helpers import aiohttp_client
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
 
-REQUIREMENTS = ['pypollencom==2.2.2']
+REQUIREMENTS = ['numpy==1.15.3', 'pypollencom==2.2.2']
 _LOGGER = logging.getLogger(__name__)
 
 ATTR_ALLERGEN_AMOUNT = 'allergen_amount'
@@ -97,7 +97,6 @@ RATING_MAPPING = [{
     'maximum': 12
 }]
 
-TREND_FLAT = 'Flat'
 TREND_INCREASING = 'Increasing'
 TREND_SUBSIDING = 'Subsiding'
 
@@ -140,6 +139,23 @@ def calculate_average_rating(indices):
     return max(set(ratings), key=ratings.count)
 
 
+def calculate_trend(indices):
+    """Calculate the "moving average" of a set of indices."""
+    import numpy as np
+
+    def moving_average(data, samples):
+        """Determine the "moving average" (http://tinyurl.com/yaereb3c)."""
+        ret = np.cumsum(data, dtype=float)
+        ret[samples:] = ret[samples:] - ret[:-samples]
+        return ret[samples - 1:] / samples
+
+    increasing = np.all(np.diff(moving_average(np.array(indices), 4)) > 0)
+
+    if increasing:
+        return TREND_INCREASING
+    return TREND_SUBSIDING
+
+
 class BaseSensor(Entity):
     """Define a base Pollen.com sensor."""
 
@@ -217,19 +233,11 @@ class ForecastSensor(BaseSensor):
             if i['minimum'] <= average <= i['maximum']
         ]
 
-        slope = (data['periods'][-1]['Index'] - data['periods'][-2]['Index'])
-        if slope > 0:
-            trend = TREND_INCREASING
-        elif slope < 0:
-            trend = TREND_SUBSIDING
-        else:
-            trend = TREND_FLAT
-
         self._attrs.update({
             ATTR_CITY: data['City'].title(),
             ATTR_RATING: rating,
             ATTR_STATE: data['State'],
-            ATTR_TREND: trend,
+            ATTR_TREND: calculate_trend(indices),
             ATTR_ZIP_CODE: data['ZIP']
         })
 
@@ -256,19 +264,11 @@ class HistoricalSensor(BaseSensor):
         indices = [p['Index'] for p in data['periods']]
         average = round(mean(indices), 1)
 
-        slope = (data['periods'][-1]['Index'] - data['periods'][-2]['Index'])
-        if slope > 0:
-            trend = TREND_INCREASING
-        elif slope < 0:
-            trend = TREND_SUBSIDING
-        else:
-            trend = TREND_FLAT
-
         self._attrs.update({
             ATTR_CITY: data['City'].title(),
             ATTR_RATING: calculate_average_rating(indices),
             ATTR_STATE: data['State'],
-            ATTR_TREND: trend,
+            ATTR_TREND: calculate_trend(indices),
             ATTR_ZIP_CODE: data['ZIP']
         })
 

requirements_all.txt

@@ -669,6 +669,7 @@ nuheat==0.3.0
 
 # homeassistant.components.binary_sensor.trend
 # homeassistant.components.image_processing.opencv
+# homeassistant.components.sensor.pollen
 numpy==1.15.3
 
 # homeassistant.components.google

requirements_test_all.txt

@@ -118,6 +118,7 @@ mficlient==0.3.0
 
 # homeassistant.components.binary_sensor.trend
 # homeassistant.components.image_processing.opencv
+# homeassistant.components.sensor.pollen
 numpy==1.15.3
 
 # homeassistant.components.mqtt