fix bugs for helmholtz and advection

Author: GiovanniCanali

pina/equation/equation_factory.py

@@ -246,12 +246,12 @@ def equation(input_, output_):
                 )
 
             # Repeat c to ensure consistent shape for advection
-            self.c = self.c.repeat(output_.shape[0], 1)
-            if self.c.shape[1] != (len(input_lbl) - 1):
-                self.c = self.c.repeat(1, len(input_lbl) - 1)
+            c = self.c.repeat(output_.shape[0], 1)
+            if c.shape[1] != (len(input_lbl) - 1):
+                c = c.repeat(1, len(input_lbl) - 1)
 
             # Add a dimension to c for the following operations
-            self.c = self.c.unsqueeze(-1)
+            c = c.unsqueeze(-1)
 
             # Compute the time derivative and the spatial gradient
             time_der = grad(output_, input_, components=None, d="t")
@@ -262,7 +262,7 @@ def equation(input_, output_):
             tmp = tmp.transpose(-1, -2)
 
             # Compute advection term
-            adv = (tmp * self.c).sum(dim=tmp.tensor.ndim - 2)
+            adv = (tmp * c).sum(dim=tmp.tensor.ndim - 2)
 
             return time_der + adv
 

pina/problem/zoo/helmholtz.py

@@ -48,11 +48,10 @@ def __init__(self, alpha=3.0):
         :type alpha: float | int
         """
         super().__init__()
-
-        self.alpha = alpha
         check_consistency(alpha, (int, float))
+        self.alpha = alpha
 
-        def forcing_term(self, input_):
+        def forcing_term(input_):
             """
             Implementation of the forcing term.
             """