fjt.h

//
// fjt.h
//
// Copyright (C) 2001 Edward Valeev
//
// Author: Edward Valeev <evaleev@vt.edu>
// Maintainer: EV
//
// This file is part of the SC Toolkit.
//
// The SC Toolkit is free software; you can redistribute it and/or modify
// it under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// The SC Toolkit is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public License
// along with the SC Toolkit; see the file COPYING.LIB.  If not, write to
// the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
//
// The U.S. Government is granted a limited license as per AL 91-7.
//
 
#ifndef _chemistry_qc_basis_fjt_h
#define _chemistry_qc_basis_fjt_h
 
#include <util/ref/ref.h>
 
namespace sc {
 
    class Fjt: virtual public RefCount {
    public:
        Fjt();
        ~Fjt();
    virtual double *values(int J, double T) =0;
    };
 
#define TAYLOR_INTERPOLATION_ORDER 6
#define TAYLOR_INTERPOLATION_AND_RECURSION 0  // compute F_lmax(T) and then iterate down to F_0(T)? Else use interpolation only
    class Taylor_Fjt : public Fjt {
    static double relative_zero_;
    public:
    static const int max_interp_order = 8;
    
    Taylor_Fjt(unsigned int jmax, double accuracy);
    ~Taylor_Fjt();
    double *values(int J, double T);
    private:
    double **grid_;            /* Table of "exact" Fm(T) values. Row index corresponds to
                      values of T (max_T+1 rows), column index to values
                      of m (max_m+1 columns) */
    double delT_;              /* The step size for T, depends on cutoff */
    double oodelT_;            /* 1.0 / delT_, see above */
    double cutoff_;            /* Tolerance cutoff used in all computations of Fm(T) */
    int interp_order_;         /* Order of (Taylor) interpolation */
    int max_m_;                /* Maximum value of m in the table, depends on cutoff
                      and the number of terms in Taylor interpolation */
    int max_T_;                /* Maximum index of T in the table, depends on cutoff
                      and m */
    double *T_crit_;           /* Maximum T for each row, depends on cutoff;
                      for a given m and T_idx <= max_T_idx[m] use Taylor interpolation,
                      for a given m and T_idx > max_T_idx[m] use the asymptotic formula */
    double *F_;                /* Here computed values of Fj(T) are stored */
 
    class ExpensiveMath {
    public:
        ExpensiveMath(int ifac, int idf);
        ~ExpensiveMath();
        double *fac;
        double *df;
    };
    ExpensiveMath ExpMath_;
    };
 
    class FJT: public Fjt {
    private:
    double **gtable;
    
    int maxj;
    double *denomarray;
    double wval_infinity;
    int itable_infinity;
    
    double *int_fjttable;
    
    int ngtable() const { return maxj + 7; }
    public:
    FJT(int n);
    ~FJT();
    double *values(int J, double T);
    };
 
} // end of namespace sc
 
#endif // header guard
 
// Local Variables:
// mode: c++
// c-file-style: "CLJ"
// End: