namespace NumericMethods

class Gear;
class GearUserProc;
struct GearEngineContext;
class GearEngineCallback;
class GearAssistant;
typedef DoubleParamsMap GearParams;
class GearStatistics;
class GearAllocator;

class Gear
{
public:
  void set(int n, GearUserProc* derFunc, GearUserProc* jacFunc);
  void setCallback(GearEngineCallback& f) { callback = &f;}
  Message solve(const double t_begin, const double t_end, const double* y0);
  GearEngineContext engineContext;
  GearAssistant assistant;

};

class GearEngineCallback   // hook/callback object in Gear::solve()
{
 public:
  virtual bool call(const GearEngineContext&) {
    return true;  // return 'false' to cancel caller proc
  }
};

class GearAssistant
{
 public:
  GearParams     params;
  GearStatistics statistics;
};

class GearAllocator
{
 public:
  GearAllocator(Gear& owner);
  ~GearAllocator();
  bool allocateMemory(int task_dimension);
};