JacobianStates.h

#ifndef JACOBIAN_STATES_H
#define JACOBIAN_STATES_H
 
class StateFrame
{
public:
   StateFrame(const double* localStates, int firstStateIndex)
       : m_localStates(localStates)
       , m_firstStateIndex(firstStateIndex)
   {
   }
 
   explicit StateFrame(int firstStateIndex)
       : StateFrame(nullptr, firstStateIndex)
   {
   }
 
   int Local(int globalIndex) const { return globalIndex - m_firstStateIndex; }
 
   const double* State(int globalIndex) const { return m_localStates + Local(globalIndex); }
 
   const double* Global() const { return m_localStates - m_firstStateIndex; }
 
private:
   const double* m_localStates;
   int           m_firstStateIndex;
};
 
#endif