refactor infectionswithfeedback.py to allow shared infection feedback…

… strength across sites (#470)

pyrenew/latent/infectionswithfeedback.py

@@ -5,7 +5,6 @@
 import jax.numpy as jnp
 from numpy.typing import ArrayLike
 
-import pyrenew.arrayutils as au
 import pyrenew.latent.infection_functions as inf
 from pyrenew.metaclass import RandomVariable
 
@@ -168,23 +167,17 @@ def sample(
             )
         )
 
-        if inf_feedback_strength.ndim == Rt.ndim - 1:
-            inf_feedback_strength = inf_feedback_strength[jnp.newaxis]
-
-        # Making sure inf_feedback_strength spans the Rt length
-        if inf_feedback_strength.shape[0] == 1:
-            inf_feedback_strength = au.pad_edges_to_match(
-                x=inf_feedback_strength,
-                y=Rt,
-                axis=0,
-            )[0]
-        if inf_feedback_strength.shape != Rt.shape:
-            raise ValueError(
-                "Infection feedback strength must be of length 1 "
-                "or the same length as the reproduction number array. "
-                f"Got {inf_feedback_strength.shape} "
-                f"and {Rt.shape} respectively."
+        try:
+            inf_feedback_strength = jnp.broadcast_to(
+                inf_feedback_strength, Rt.shape
             )
+        except Exception as e:
+            raise ValueError(
+                "Could not broadcast inf_feedback_strength "
+                f"(shape {inf_feedback_strength.shape}) "
+                "to the shape of Rt"
+                f"{Rt.shape}"
+            ) from e
 
         # Sampling inf feedback pmf
         inf_feedback_pmf = self.infection_feedback_pmf(**kwargs)