tentative fix

nifty5/minimization/metric_gaussian_kl_mpi.py

@@ -92,18 +92,18 @@ class MetricGaussianKL_MPI(Energy):
         v, g = None, None
         if len(self._samples) == 0:  # hack if there are too many MPI tasks
             tmp = self._hamiltonian(self._lin)
-            v = 0. * tmp.val.local_data[()]
+            v = 0. * tmp.val.local_data
             g = 0. * tmp.gradient
         else:
             for s in self._samples:
                 tmp = self._hamiltonian(self._lin+s)
                 if v is None:
-                    v = tmp.val.local_data[()]
+                    v = tmp.val.local_data.copy()
                     g = tmp.gradient
                 else:
-                    v += tmp.val.local_data[()]
+                    v += tmp.val.local_data
                     g = g + tmp.gradient
-        self._val = np_allreduce_sum(v) / self._n_samples
+        self._val = np_allreduce_sum(v)[()] / self._n_samples
         self._grad = allreduce_sum_field(g) / self._n_samples
         self._metric = None