Update import of graph_laplacian

src/AMBER/background.py

@@ -3,7 +3,7 @@ import scipy
 import os.path
 
 # graph Laplacian functions
-from graph_laplacian import laplacian, unnormalized_laplacian, unnormalized_laplacian_chain, \
+from AMBER.graph_laplacian import laplacian, unnormalized_laplacian, unnormalized_laplacian_chain, \
     laplacian_chain, remove_vertex
 
 import matplotlib.pyplot as plt