add count of masked values to debug output

goesr/rockfall.py

@@ -569,6 +569,8 @@ def debug(pvda):
     """
     for P, V, D, A in pvda:
         print("{}\n{}:\n\tdim: {}\n\tatt: {}\n\tdata: {}".format('_'*64, '/'.join(P), repr(D), repr(A), repr(V)))
+        if hasattr(V, 'mask'):
+            print("{}/{} values masked".format(np.sum(V.mask.ravel()), len(V.mask.ravel())))
         yield P, V, D, A