Fix transformation of rate matrix

tardis/plasma/equilibrium/level_populations.py

@@ -61,7 +61,7 @@ def solve(self):
                 )
             )
             normalized_level_populations.loc[species_id, :].update(
-                np.hstack(solved_matrices.values)
+                np.vstack(solved_matrices.values).T
             )
 
         return normalized_level_populations