Add total entities metric

Author: LadyChristina

config.yaml

@@ -12,6 +12,7 @@ metrics:
   tau_index:
     - 0.33
     - 0.66
+  total_entities:
 
 # The ledgers for which an analysis should be performed.
 ledgers:

consensus_decentralization/analyze.py

@@ -8,6 +8,7 @@
 from consensus_decentralization.metrics.theil_index import compute_theil_index  # noqa: F401
 from consensus_decentralization.metrics.max_power_ratio import compute_max_power_ratio  # noqa: F401
 from consensus_decentralization.metrics.tau_index import compute_tau_index  # noqa: F401
+from consensus_decentralization.metrics.total_entities import compute_total_entities  # noqa: F401
 
 
 def analyze(projects, aggregated_data_filename, output_dir):

consensus_decentralization/metrics/entropy.py

@@ -1,4 +1,5 @@
 from math import log
+from consensus_decentralization.metrics.total_entities import compute_total_entities
 
 
 def compute_entropy(block_distribution, alpha):
@@ -41,6 +42,8 @@ def compute_entropy_percentage(block_distribution, alpha):
     if sum(block_distribution) == 0:
         return None
     try:
-        return compute_entropy(block_distribution, alpha) / compute_max_entropy(len(block_distribution), alpha)
+        total_entities = compute_total_entities(block_distribution)
+        return compute_entropy(block_distribution, alpha) / compute_max_entropy(total_entities, alpha)
     except ZeroDivisionError:
         return 0
+

consensus_decentralization/metrics/total_entities.py

@@ -0,0 +1,7 @@
+def compute_total_entities(block_distribution):
+    """
+    Computes the number of entities that have produced blocks in the given timeframe.
+    :param block_distribution: list of integers, each being the blocks that an entity has produced
+    :returns: an integer that represents the number of entities that have produced blocks
+    """
+    return len([v for v in block_distribution if v > 0])

tests/test_metrics.py

@@ -1,5 +1,5 @@
 from consensus_decentralization.metrics import (entropy, gini, nakamoto_coefficient, herfindahl_hirschman_index,
-                                                theil_index, max_power_ratio, tau_index)
+                                                theil_index, max_power_ratio, tau_index, total_entities)
 import numpy as np
 
 
@@ -177,3 +177,14 @@ def test_tau_66():
 
     tau_idx = tau_index.compute_tau_index([1], threshold=0.66)
     assert tau_idx == 1
+
+
+def test_total_entities():
+    entity_count = total_entities.compute_total_entities(block_distribution=[1, 2, 3])
+    assert entity_count == 3
+
+    entity_count = total_entities.compute_total_entities(block_distribution=[0])
+    assert entity_count == 0
+
+    entity_count = total_entities.compute_total_entities(block_distribution=[5, 0, 0])
+    assert entity_count == 1