class PCBCGSolver{ public:   int N;  unsigned long *ija;  double *sa;  PCBCGSolver(int nonzeroelement){    ija = new unsigned long[nonzeroelement+2];    sa = new double[nonzeroelement+2];  }  virtual ~PCBCGSolver(){    delete [] ija;    delete [] sa;  }  void PCBCGSolver::linbcg(unsigned long n, double b[], double x[], int itol, double tol,int itmax, int *iter, double *err);   private:  PCBCGSolver(const PCBCGSolver& rhs);  const PCBCGSolver &operator=(const PCBCGSolver& rhs);  void PCBCGSolver::dsprsax(double sa[], unsigned long ija[], double x[], double b[], unsigned long n);  void PCBCGSolver::asolve(unsigned long n, double b[], double x[], int itrnsp);  void PCBCGSolver::atimes(unsigned long n, double x[], double r[], int itrnsp);  void PCBCGSolver::dsprstx(double sa[], unsigned long ija[], double x[], double b[], unsigned long n);  double PCBCGSolver::snrm(unsigned long n, double sx[], int itol);  };