function [out1,out2,out3] = ode1_file(t,y,flag,p1,p2)
if nargin < 3 | isempty(flag)
  % Return dy/dt = F(t,y).
  out1 = < Insert a function of t and/or y, p1, and p2 here. >
  
  else
      switch(flag)
      case 'init'                       % Return default [tspan,y0,options].
        out1 = < Insert tspan here. >;
        out2 = < Insert y0 here. >;
        out3 = < Insert options = odeset(...) or [] here. >;
      
      case 'jacobian'                   % Return matrix J(t,y) = dF/dy.
        out1 = < Insert Jacobian matrix here. >;
    
      case 'jpattern'                   % Return sparsity pattern matrix S.
        out1 = < Insert Jacobian matrix sparsity pattern here. >;
    
      case 'mass'                       % Return mass matrix M(t) or M.
        out1 = < Insert mass matrix here. >;
    
      case 'events'                     % Return event vector and information.
        out1 = < Insert event function vector here. >
        out2 = < Insert logical ISTERMINAL vector here.>;
        out3 = < Insert DIRECTION vector here.>;
    
      otherwise
    error(['Unknown flag ''' flag '''.']);
      end
end