Sharpe ratio is working

fincal/fincal.py

@@ -449,7 +449,7 @@ class TimeSeries(TimeSeriesCore):
         prior_match: str = "closest",
         closest: Literal["previous", "next", "exact"] = "previous",
         if_not_found: Literal["fail", "nan"] = "fail",
-        annual_compounded_returns: bool = False,
+        annual_compounded_returns: bool = None,
         date_format: str = None,
     ) -> float:
         """Calculates the volatility of the time series.add()
@@ -503,6 +503,12 @@ class TimeSeries(TimeSeriesCore):
             from_date = self.start_date + relativedelta(**{return_period_unit: return_period_value})
         if to_date is None:
             to_date = self.end_date
+        years = _interval_to_years(return_period_unit, return_period_value)
+        if annual_compounded_returns is None:
+            if years > 1:
+                annual_compounded_returns = True
+            else:
+                annual_compounded_returns = False
 
         rolling_returns = self.calculate_rolling_returns(
             from_date=from_date,
@@ -524,7 +530,7 @@ class TimeSeries(TimeSeriesCore):
             if return_period_unit == "months":
                 sd *= math.sqrt(12)
             elif return_period_unit == "days":
-                sd *= math.sqrt(traded_days)
+                sd *= math.sqrt(traded_days / return_period_value)
 
         return sd
 
@@ -544,19 +550,32 @@ class TimeSeries(TimeSeriesCore):
         ---------
         TimeSeries.calculate_rolling_returns()
         """
-
         kwargs["return_period_unit"] = kwargs.get("return_period_unit", self.frequency.freq_type)
         kwargs["return_period_value"] = kwargs.get("return_period_value", 1)
-        kwargs["to_date"] = kwargs.get("to_date", self.end_date)
 
-        if kwargs.get("from_date", None) is None:
-            start_date = self.start_date + relativedelta(
+        years = _interval_to_years(kwargs["return_period_unit"], kwargs["return_period_value"])
+        if kwargs.get("annual_compounded_returns", True):
+            if years >= 1:
+                kwargs["annual_compounded_returns"] = True
+                annualise_returns = False
+            else:
+                kwargs["annual_compounded_returns"] = False
+                annualise_returns = True
+        elif not kwargs["annual_compounded_returns"]:
+            annualise_returns = False
+
+        if kwargs.get("from_date") is None:
+            kwargs["from_date"] = self.start_date + relativedelta(
                 **{kwargs["return_period_unit"]: kwargs["return_period_value"]}
             )
-            kwargs["from_date"] = start_date
+        kwargs["to_date"] = kwargs.get("to_date", self.end_date)
 
         rr = self.calculate_rolling_returns(**kwargs)
-        return statistics.mean(rr.values)
+        mean_rr = statistics.mean(rr.values)
+        if annualise_returns:
+            mean_rr = (1 + mean_rr) ** (1 / years) - 1
+
+        return mean_rr
 
     def max_drawdown(self) -> MaxDrawdown:
         """Calculates the maximum fall the stock has taken between any two points.

fincal/statistics.py

@@ -21,10 +21,10 @@ def sharpe_ratio(
     closest: Literal["previous", "next"] = "previous",
     date_format: str = None,
 ):
-    pass
-
     if risk_free_data is None and risk_free_rate is None:
         raise ValueError("At least one of risk_free_data or risk_free rate is required")
+    elif risk_free_data is not None:
+        risk_free_rate = risk_free_data.mean()
 
     common_params = {
         "from_date": from_date,
@@ -37,18 +37,13 @@ def sharpe_ratio(
         "closest": closest,
         "date_format": date_format,
     }
-    returns_ts = time_series_data.calculate_rolling_returns(**common_params, annual_compounded_returns=True)
+    average_rr = time_series_data.average_rolling_return(**common_params, annual_compounded_returns=True)
 
-    if risk_free_data is not None:
-        risk_free_data = returns_ts.sync(risk_free_data)
-    else:
-        risk_free_data = risk_free_rate
-
-    excess_returns = returns_ts - risk_free_data
+    excess_returns = average_rr - risk_free_rate
     sd = time_series_data.volatility(
         **common_params,
         annualize_volatility=True,
     )
 
-    sharpe_ratio = excess_returns.mean() / sd
-    return sharpe_ratio
+    sharpe_ratio_value = excess_returns / sd
+    return sharpe_ratio_value

tests/test_fincal.py

@@ -206,6 +206,8 @@ class TestTimeSeriesCreation:
 
 
 class TestTimeSeriesBasics:
+    FincalOptions.get_closest = "exact"
+
     def test_fill(self):
         ts_data = create_test_data(frequency=AllFrequencies.D, num=50, skip_weekends=True)
         ts = TimeSeries(ts_data, frequency="D")