Fix Rician arguments

comyx/network/links.py

@@ -8,14 +8,16 @@
 from ..fading import get_rvs
 from ..propagation import get_pathloss
 from ..utils import db2pow, ensure_list, get_distance
+from .ris import RIS, STAR_RIS
 
 if TYPE_CHECKING:
-    from .ris import RIS
     from .transceiver import Transceiver
 
 NDArrayFloat = npt.NDArray[np.floating[Any]]
 NDArrayComplex = npt.NDArray[np.complexfloating[Any, Any]]
 
+EPSILON = np.finfo(float).eps
+
 
 class Link:
     r"""Represents a link in the modelled environment.
@@ -129,7 +131,7 @@ def generate_rvs(
         Not private to allow for the generation of new channel gains for more
         flexible simulations.
         """
-        if custom_rvs is None:
+        if custom_rvs is None and self._rician_args is None:
             self.rvs = get_rvs(self.shape, **self._fading_args, seed=seed)
         elif self._rician_args is not None:
             self.rvs = self.rician_fading(**self._rician_args)
@@ -207,12 +209,12 @@ def rician_fading(
         los = []
         if order == "post":
             assert isinstance(
-                self.rx, RIS
+                self.rx, (RIS, STAR_RIS)
             ), "The receiver must be an RIS for the post-order Rician fading."
             n_elements = self.rx.n_elements
         elif order == "pre":
             assert isinstance(
-                self.tx, RIS
+                self.tx, (RIS, STAR_RIS)
             ), "The transmitter must be an RIS for the pre-order Rician fading."
             n_elements = self.tx.n_elements
         else:
@@ -226,15 +228,15 @@ def rician_fading(
                     * np.pi
                     * (self.rx.position[1] - self.tx.position[1])
                     / (
-                        np.sqrt(
-                            (self.rx.position[0] - self.tx.position[0]) ** 2
-                            + (self.rx.position[1] - self.tx.position[1]) ** 2
+                        np.sqrt(  # EPSILON is a small value to avoid division by zero
+                            (self.rx.position[0] - self.tx.position[0] + EPSILON) ** 2
+                            + (self.rx.position[1] - self.tx.position[1] + EPSILON) ** 2
                         )
                     )
                 )
             )
 
-        los = np.array(los).reshape(self.shape)
+        los = np.array(np.repeat(los, self.shape[-1])).reshape(self.shape)
         nlos = get_rvs(self.shape, **self._fading_args, seed=self.seed)
         rvs = los * (np.sqrt(K / (K + 1))) + nlos * (1 / (np.sqrt(K + 1)))