Model is unsuitably constrained (i.e. there were still some variables left to be computed, and some unusable equations left over).
At the time of the error, the following variables were found:
 * Undefined: v in component gating_If
 * Undefined: alpha_act in component gating_If
 * Undefined: beta_act in component gating_If
 * Undefined: xf_1 in component gating_If
 * Undefined: xf_2 in component gating_If
 * Undefined: xf_3 in component gating_If
 * Undefined: xf_4 in component gating_If
 * Undefined: xf_5 in component gating_If
 * Undefined: xf_6 in component gating_If
 * Undefined: xf_const in component gating_If
 * Undefined: x_f_inf_act in component gating_If
 * Undefined: tau_f_act in component gating_If
The following equations couldn't be used:
 * Equation with no id on the apply or math element.
 * Equation with no id on the apply or math element.
 * Equation with no id on the apply or math element.
 * Equation with no id on the apply or math element.
 * Equation with no id on the apply or math element.
 * Equation with no id on the apply or math element.