text: /**
   * 2014--6--18
   * ode.h
   */
  #ifndef _ODE_H_
  #define _ODE_H_
  
  /**
   * Requires at least
   * dt - delta t
   * neq - number of equations
   */
  struct PARAMETER {
      int neq;
      int nt;
      double ti;
      double tf;
      double dt;
  };
  
  struct BUTCHER {
    int S;
    double * b;
    double * c;
    double ** A;
    
  };
  
  void rhs(double t, double *u, PARAMETER param, double* f);
  void newt(double t, double *uprev, double * Kguess,
  	  double *g, PARAMETER param, BUTCHER rk);
  void jac(double t, double *uprev, double * Kguess,
  	 double *J, PARAMETER param, BUTCHER rk);
  void step(double t, double* u, PARAMETER param, double* unew, BUTCHER rk);
  
  #endif // _ODE_H_
  