src/lib/chemistry/qc/basis/orthog.h

//
// orthog.h -- orthogonalize the basis set
//
// Copyright (C) 1996 Limit Point Systems, Inc.
//
// Author: Curtis Janssen <cljanss@ca.sandia.gov>
// Maintainer: LPS
//
// 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_orthog_h
#define _chemistry_qc_basis_orthog_h

#include <util/state/state.h>
#include <math/scmat/matrix.h>

namespace sc {

class OverlapOrthog: virtual public SavableState {
  public:

    enum OrthogMethod { Symmetric=1, Canonical=2, GramSchmidt=3 };
    static OrthogMethod default_orthog_method() { return Symmetric; }
    static double default_lindep_tol() { return 1e-8; }

  private:
    int debug_;

    RefSCDimension dim_;
    RefSCDimension orthog_dim_;

    // The tolerance for linearly independent basis functions.
    // The intepretation depends on the orthogonalization method.
    double lindep_tol_;
    // The number of linearly dependent functions
    int nlindep_;
    // The orthogonalization method
    OrthogMethod orthog_method_;
    // The orthogonalization matrices
    RefSCMatrix orthog_trans_;
    RefSCMatrix orthog_trans_inverse_;
    // The maximum and minimum residuals from the orthogonalization
    // procedure.  The interpretation depends on the method used.
    // For symmetry and canonical, these are the min and max overlap
    // eigenvalues.  These are the residuals for the basis functions
    // that actually end up being used.
    double min_orthog_res_;
    double max_orthog_res_;

    void compute_overlap_eig(RefSCMatrix& overlap_eigvec,
                             RefDiagSCMatrix& overlap_isqrt_eigval,
                             RefDiagSCMatrix& overlap_sqrt_eigval);
    void compute_symmetric_orthog();
    void compute_canonical_orthog();
    void compute_gs_orthog();
    void compute_orthog_trans();

    // WARNING: after a SavableState save/restore, these two members will
    // be null.  There is really no need to store these anyway--should be
    // removed.
    RefSymmSCMatrix overlap_;
    Ref<SCMatrixKit> result_kit_; // this kit is used for the result matrices

  public:
    OverlapOrthog(OrthogMethod method,
                  const RefSymmSCMatrix &overlap,
                  const Ref<SCMatrixKit> &result_kit,
                  double lindep_tolerance,
                  int debug = 0);

    OverlapOrthog(StateIn&);

    virtual ~OverlapOrthog();

    void save_data_state(StateOut&);

    void reinit(OrthogMethod method,
                const RefSymmSCMatrix &overlap,
                const Ref<SCMatrixKit> &result_kit,
                double lindep_tolerance,
                int debug = 0);

    double min_orthog_res() const { return min_orthog_res_; }
    double max_orthog_res() const { return max_orthog_res_; }

    Ref<OverlapOrthog> copy() const;

    OrthogMethod orthog_method() const { return orthog_method_; }

    double lindep_tol() const { return lindep_tol_; }

    RefSCMatrix basis_to_orthog_basis();

    RefSCMatrix basis_to_orthog_basis_inverse();

    RefSymmSCMatrix overlap_inverse();

    RefSCDimension dim();
    RefSCDimension orthog_dim();

    int nlindep();
};

}

#endif

---