diff --git a/src/specFunctions.py b/src/specFunctions.py
index 0f097f7..236a099 100644
--- a/src/specFunctions.py
+++ b/src/specFunctions.py
@@ -135,7 +135,7 @@ def savitzky_golay(y, window_size, order, deriv=0, rate=1):
 	order_range = range(order+1)
 	half_window = (window_size -1) // 2
 	# precompute coefficients
-	b = np.mat([[k**i for i in order_range] for k in range(-half_window, half_window+1)])
+	b = np.asmatrix([[k**i for i in order_range] for k in range(-half_window, half_window+1)])
 	m = np.linalg.pinv(b).A[deriv] * rate**deriv * factorial(deriv)
 	# pad the signal at the extremes with
 	# values taken from the signal itself