Model is underconstrained. The following variables couldn't be defined: * V_initial in component action_potential * n_initial in component action_potential * m_initial in component action_potential * h_initial in component action_potential * Istim in component action_potential * INa in component INa * IK in component IK * Ileak in component Ileak * gK in component IK * gNa in component INa * g in component action_potential * X in component hh_gating_variable * T in component action_potential * minus_V in component action_potential * VNa in component action_potential * VK in component action_potential * Vleak in component action_potential * gNa_max in component action_potential * gK_max in component action_potential * gleak_max in component action_potential * Cm in component action_potential * alpha in component alpha_m * phi in component temperature_factor * beta in component beta_m * alpha in component alpha_h * beta in component beta_h * alpha in component alpha_n * phi in component temperature_factor * beta in component beta_n * d/dt V in component action_potential * d/dt X in component hh_gating_variable * d/dt X in component hh_gating_variable * d/dt X in component hh_gating_variable