seed: use Ellipsis to indicate keeping the seed

src/gstools/field/cond_srf.py

@@ -65,7 +65,7 @@ def __init__(self, krige, generator="RandMeth", **generator_kwargs):
     def __call__(
         self,
         pos=None,
-        seed=np.nan,
+        seed=...,
         mesh_type="unstructured",
         post_process=True,
         store=True,
@@ -81,8 +81,10 @@ def __call__(
         pos : :class:`list`, optional
             the position tuple, containing main direction and transversal
             directions
-        seed : :class:`int`, optional
-            seed for RNG for resetting. Default: keep seed from generator
+        seed : :class:`int` or :any:`None` or :any:`Ellipsis`, optional
+            the seed of the random number generator.
+            If :any:`None`, a random seed is used. If :any:`Ellipsis`,
+            the actual seed will be kept. Default: :any:`Ellipsis`
         mesh_type : :class:`str`
             'structured' / 'unstructured'
         post_process : :class:`bool`, optional

src/gstools/field/generator.py

@@ -51,7 +51,7 @@ def __init__(self, model, **kwargs):
         pass
 
     @abstractmethod
-    def update(self, model=None, seed=np.nan):
+    def update(self, model=None, seed=...):
         """Update the model and the seed.
 
         If model and seed are not different, nothing will be done.
@@ -60,10 +60,10 @@ def update(self, model=None, seed=np.nan):
         ----------
         model : :any:`CovModel` or :any:`None`, optional
             covariance model. Default: :any:`None`
-        seed : :class:`int` or :any:`None` or :any:`numpy.nan`, optional
+        seed : :class:`int` or :any:`None` or :any:`Ellipsis`, optional
             the seed of the random number generator.
-            If :any:`None`, a random seed is used. If :any:`numpy.nan`,
-            the actual seed will be kept. Default: :any:`numpy.nan`
+            If :any:`None`, a random seed is used. If :any:`Ellipsis`,
+            the actual seed will be kept. Default: :any:`Ellipsis`
         """
 
     @abstractmethod
@@ -238,7 +238,7 @@ def get_nugget(self, shape):
             nugget = 0.0
         return nugget
 
-    def update(self, model=None, seed=np.nan):
+    def update(self, model=None, seed=...):
         """Update the model and the seed.
 
         If model and seed are not different, nothing will be done.
@@ -247,32 +247,32 @@ def update(self, model=None, seed=np.nan):
         ----------
         model : :any:`CovModel` or :any:`None`, optional
             covariance model. Default: :any:`None`
-        seed : :class:`int` or :any:`None` or :any:`numpy.nan`, optional
+        seed : :class:`int` or :any:`None` or :any:`Ellipsis`, optional
             the seed of the random number generator.
-            If :any:`None`, a random seed is used. If :any:`numpy.nan`,
-            the actual seed will be kept. Default: :any:`numpy.nan`
+            If :any:`None`, a random seed is used. If :any:`Ellipsis`,
+            the actual seed will be kept. Default: :any:`Ellipsis`
         """
         # check if a new model is given
         if isinstance(model, CovModel):
             if self.model != model:
                 self._model = dcp(model)
-                if seed is None or not np.isnan(seed):
+                if seed is None or seed is not Ellipsis:
                     self.reset_seed(seed)
                 else:
                     self.reset_seed(self._seed)
             # just update the seed, if its a new one
-            elif seed is None or not np.isnan(seed):
+            elif seed is None or seed is not Ellipsis:
                 self.seed = seed
         # or just update the seed, when no model is given
-        elif model is None and (seed is None or not np.isnan(seed)):
+        elif model is None and (seed is None or seed is not Ellipsis):
             if isinstance(self._model, CovModel):
                 self.seed = seed
             else:
                 raise ValueError(
                     "gstools.field.generator.RandMeth: no 'model' given"
                 )
         # if the user tries to trick us, we beat him!
-        elif model is None and np.isnan(seed):
+        elif model is None and seed is Ellipsis:
             if (
                 isinstance(self._model, CovModel)
                 and self._z_1 is not None
@@ -293,22 +293,22 @@ def update(self, model=None, seed=np.nan):
                 "instance of 'gstools.CovModel'"
             )
 
-    def reset_seed(self, seed=np.nan):
+    def reset_seed(self, seed=...):
         """
         Recalculate the random amplitudes and wave numbers with the given seed.
 
         Parameters
         ----------
-        seed : :class:`int` or :any:`None` or :any:`numpy.nan`, optional
+        seed : :class:`int` or :any:`None` or :any:`Ellipsis`, optional
             the seed of the random number generator.
-            If :any:`None`, a random seed is used. If :any:`numpy.nan`,
-            the actual seed will be kept. Default: :any:`numpy.nan`
+            If :any:`None`, a random seed is used. If :any:`Ellipsis`,
+            the actual seed will be kept. Default: :any:`Ellipsis`
 
         Notes
         -----
         Even if the given seed is the present one, modes will be recalculated.
         """
-        if seed is None or not np.isnan(seed):
+        if seed is None or seed is not Ellipsis:
             self._seed = seed
         self._rng = RNG(self._seed)
         # normal distributed samples for randmeth

src/gstools/field/srf.py

@@ -104,7 +104,7 @@ def __init__(
     def __call__(
         self,
         pos=None,
-        seed=np.nan,
+        seed=...,
         point_volumes=0.0,
         mesh_type="unstructured",
         post_process=True,
@@ -119,8 +119,10 @@ def __call__(
         pos : :class:`list`, optional
             the position tuple, containing main direction and transversal
             directions
-        seed : :class:`int`, optional
-            seed for RNG for resetting. Default: keep seed from generator
+        seed : :class:`int` or :any:`None` or :any:`Ellipsis`, optional
+            the seed of the random number generator.
+            If :any:`None`, a random seed is used. If :any:`Ellipsis`,
+            the actual seed will be kept. Default: :any:`Ellipsis`
         point_volumes : :class:`float` or :class:`numpy.ndarray`
             If your evaluation points for the field are coming from a mesh,
             they are probably representing a certain element volume.