Fix Issue #2577 - Zero Division Error in diagnostics.performance_metr…

…ics() causing failed assertion (#2578)

python/prophet/diagnostics.py

@@ -630,6 +630,7 @@ def smape(df, w):
  Dataframe with columns horizon and smape.
  """
  sape = np.abs(df['y'] - df['yhat']) / ((np.abs(df['y']) + np.abs(df['yhat'])) / 2)
+ sape = sape.fillna(0)
  if w < 0:
  return pd.DataFrame({'horizon': df['horizon'], 'smape': sape})
  return rolling_mean_by_h(

python/prophet/tests/test_diagnostics.py

@@ -241,6 +241,13 @@ def test_performance_metrics(self, ts_short, backend):
  metrics=["coverage", "mape"],
  )
  assert set(df_horizon.columns) == {"coverage", "horizon"}
+ # Handle zero y and yhat
+ df_cv["y"] = 0.0
+ df_cv["yhat"] = 0.0
+ df_horizon = diagnostics.performance_metrics(
+ df_cv,
+ )
+ assert set(df_horizon.columns) == {"coverage", "horizon", "mae", "mdape", "mse", "rmse", "smape"}
  df_horizon = diagnostics.performance_metrics(
  df_cv,
  metrics=["mape"],