Update docstrings of functions that convert between simple and log re…

…turns (#128)

deepdow/losses.py

@@ -36,38 +36,38 @@ def covariance(x, y):
 
 
 def log2simple(x):
-    """Turn simple returns into log returns.
+    """Turn log returns into simple returns.
 
     r_simple = exp(r_log) - 1.
 
     Parameters
     ----------
     x : torch.Tensor
-        Tensor of any shape where each entry represents a simple return.
+        Tensor of any shape where each entry represents a logarithmic return.
 
     Returns
     -------
     torch.Tensor
-        Logarithmic returns.
+        Simple returns.
 
     """
     return torch.exp(x) - 1
 
 
 def simple2log(x):
-    """Turn log returns into simple returns.
+    """Turn simple returns into log returns.
 
     r_log = ln(r_simple + 1).
 
     Parameters
     ----------
     x : torch.Tensor
-        Tensor of any shape where each entry represents a logarithmic return.
+        Tensor of any shape where each entry represents a simple return.
 
     Returns
     -------
     torch.Tensor
-        Simple returns.
+        Logarithmic returns.
 
     """
     return torch.log(x + 1)