fix: reaction bounds in _add_cycle_free function are assigned accordi…

…ng to the description in CycleFreeFlux paper

src/cobra/flux_analysis/loopless.py

@@ -112,10 +112,10 @@ def _add_cycle_free(model: "Model", fluxes: Dict[str, float]) -> None:
             rxn.bounds = (flux, flux)
             continue
         if flux >= 0:
-            rxn.bounds = max(0, rxn.lower_bound), max(flux, rxn.upper_bound)
+            rxn.bounds = max(0, rxn.lower_bound), min(flux, rxn.upper_bound)
             objective_vars.append(rxn.forward_variable)
         else:
-            rxn.bounds = min(flux, rxn.lower_bound), min(0, rxn.upper_bound)
+            rxn.bounds = max(flux, rxn.lower_bound), min(0, rxn.upper_bound)
             objective_vars.append(rxn.reverse_variable)
 
     model.objective.set_linear_coefficients({v: 1.0 for v in objective_vars})