Change the way ani. fields are handled by Fourier

src/gstools/field/generator.py

@@ -678,7 +678,8 @@ def update(self, model=None, seed=np.nan, period=None, mode_no=None):
         tmp_model = model if model is not None else self._model
         if period is not None:
             self._period = self._fill_to_dim(period, tmp_model.dim)
-            self._delta_k = 2.0 * np.pi / self._period
+            anis = np.insert(tmp_model.anis.copy(), 0, 1.0)
+            self._delta_k = 2. * np.pi / self._period * anis
             if mode_no is None:
                 self._set_modes(self._mode_no, tmp_model)
         if mode_no is not None:
@@ -791,11 +792,10 @@ def _set_modes(self, mode_no, model):
         -----
         `self._reset_seed` *has* to be called after this method!
         """
-        anis = np.insert(model.anis.copy(), 0, 1.0)
         modes = [
             np.arange(
-                -mode_no[d] / 2.0 * self._delta_k[d] / anis[d],
-                mode_no[d] / 2.0 * self._delta_k[d] / anis[d],
+                -mode_no[d] / 2.0 * self._delta_k[d],
+                mode_no[d] / 2.0 * self._delta_k[d],
                 self._delta_k[d],
             )
             for d in range(model.dim)