more fixes

nifty6/operators/convolution_operators.py

@@ -88,7 +88,7 @@ class _ApplicationWithoutMeanOperator(EndomorphicOperator):
 
     def apply(self, x, mode):
         self._check_input(x, mode)
-        mean = x.mean()
+        mean = x.s_mean()
         return mean + self._op.apply(x - mean, mode)
 
     def __repr__(self):

nifty6/sugar.py

@@ -92,7 +92,7 @@ def get_signal_variance(spec, space):
     field = PS_field(space, spec)
     dist = PowerDistributor(space.harmonic_partner, space)
     k_field = dist(field)
-    return k_field.weight(2).sum()
+    return k_field.weight(2).s_sum()
 
 
 def _single_power_analyze(field, idx, binbounds):