[bugfix] Fix horizontal_index extraction

python/dune/perftool/sumfact/symbolic.py

@@ -569,10 +569,11 @@ class VectorizedSumfactKernel(SumfactKernelBase, ImmutableRecord, prim.Variable)
         return True
 
     def horizontal_index(self, sf):
-        key = tuple(mat.derivative for mat in sf.matrix_sequence)
         for i, k in enumerate(self.kernels):
-            if tuple(mat.derivative for mat in k.matrix_sequence) == key:
-                return i
+            if sf.input_key == k.input_key:
+                if tuple(mat.derivative for mat in sf.matrix_sequence) == tuple(mat.derivative for mat in k.matrix_sequence):
+                    return i
+
         return 0
 
     def _quadrature_index(self, sf, visitor):