fix residual stack (#772)

GiovanniCanali · web-flow · commit bfb9928cd3f2 · 2026-02-25T15:49:35.000+01:00
diff --git a/pina/_src/equation/system_equation.py b/pina/_src/equation/system_equation.py
@@ -105,11 +105,12 @@ def residual(self, input_, output_, params_=None):
         self.to(input_.device)
 
         # Compute the residual for each equation
-        residual = torch.hstack(
+        residual = torch.cat(
             [
                 equation.residual(input_, output_, params_)
                 for equation in self.equations
-            ]
+            ],
+            dim=-1,
         )
 
         # Skip reduction if not specified

Original file line number	Diff line number	Diff line change
`@@ -105,11 +105,12 @@ def residual(self, input_, output_, params_=None):`
`105`	`105`	`self.to(input_.device)`
`106`	`106`
`107`	`107`	`# Compute the residual for each equation`
`108`		`- residual = torch.hstack(`
	`108`	`+ residual = torch.cat(`
`109`	`109`	`[`
`110`	`110`	`equation.residual(input_, output_, params_)`
`111`	`111`	`for equation in self.equations`
`112`		`- ]`
	`112`	`+ ],`
	`113`	`+ dim=-1,`
`113`	`114`	`)`
`114`	`115`
`115`	`116`	`# Skip reduction if not specified`