automatically coerce coerce coefficients for SV smoothing

larch/math/utils.py

@@ -409,11 +409,11 @@ def savitzky_golay(y, window_size, order, deriv=0):
         window_size = abs(int(window_size))
         order = abs(int(order))
     except ValueError:
-        raise ValueError("window_size and order have to be of type int")
-    if window_size % 2 != 1 or window_size < 1:
-        raise TypeError("window_size size must be a positive odd number")
+        raise ValueError("window_size and order must be integers")
     if window_size < order + 2:
-        raise TypeError("window_size is too small for the polynomials order")
+        window_size = order + 3
+    if window_size % 2 != 1 or window_size < 1:
+        window_size = window_size + 1
     order_range = range(order+1)
     half_window = (window_size -1) // 2
     # precompute coefficients