arpack_d.h

// -*- mode: c++; fill-column: 80; c-basic-offset: 2; indent-tabs-mode: nil -*-
/*
    Copyright (c) 2010 Juan Jose Garcia Ripoll

    Tensor 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 of the License, or
    (at your option) any later version.

    This program 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 General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#ifndef TENSOR_ARPACK_D_H
#define TENSOR_ARPACK_D_H

#include <tensor/tensor_blas.h>
#include <tensor/linalg.h>

namespace linalg {

class RArpack {
 public:
    typedef double elt_t;
    typedef blas::integer integer;

    enum Status {
        Uninitialized = 0,
        Initialized = 1,
        Running = 2,
        Finished = 3,
        Error = 4,
        TooManyIterations = 5,
        NoConvergence = 6,
    };

    RArpack(size_t n, enum EigType t, size_t neig);
    ~RArpack();
    void set_random_start_vector();
    void set_start_vector(const elt_t *v);
    void set_tolerance(double tol);
    void set_maxiter(size_t maxiter);
    enum Status update();
    elt_t *get_x_vector();
    elt_t *get_y_vector();
    const tensor::RTensor get_x();
    tensor::RTensor get_y();
    void set_y(const tensor::RTensor &y);
    tensor::RTensor get_data(tensor::RTensor *vectors);
    tensor::RTensor get_data(double *z);
    std::string error_message() { return std::string(error); };
    enum Status get_status() { return status; };
    size_t get_vector_size() { return n; };

    void prepare();
    void clear();

    static tensor::Indices sort_values(const tensor::CTensor &t, EigType selector);

 protected:
    enum Status status;
    enum EigType which_eig;

    integer n;          // Dimension of the eigenproblem.
    integer nev;        // Number of eigenvalues to be computed. 0 < nev < n-1.
    integer ncv;        // Number of Arnoldi vectors generated at each iteration.
    integer maxit;      // Maximum number of Arnoldi update iterations allowed.
    const char* which;  // Specify which of the Ritz values of OP to compute.
    double  tol;        // Stopping criterion (relative accuracy of Ritz values).
    elt_t   sigma;      // Shift (for nonsymmetric problems).
    elt_t   *resid;     // Initial residual vector.

    // a.2) Internal variables.

    bool    symmetric;  // Symmetric matrix, or not
    bool    rvec;       // Indicates if eigenvectors/Schur vectors were
                        // requested (or only eigenvalues will be determined).
    char    bmat;       // Indicates if the problem is a standard ('I') or
                        // generalized ('G") eigenproblem.
    char    hwmny;      // Indicates if eigenvectors ('A') or Schur vectors ('P')
                        // were requested (not referenced if rvec = false).
    integer ido;        // Original ARPACK reverse communication flag.
    integer info;       // Original ARPACK error flag.
    integer mode;       // Indicates the type of the eigenproblem (regular,
                        // shift and invert, etc).
    integer lworkl;     // Dimension of array workl.
    integer lworkv;     // Dimension of array workv.
    integer lrwork;     // Dimension of array rwork.
    integer iparam[12]; // RVector that handles original ARPACK parameters.
    integer ipntr[15];  // RVector that handles original ARPACK pointers.
    double  *rwork;     // Original ARPACK internal vector.
    elt_t   *workl;     // Original ARPACK internal vector.
    elt_t   *workd;     // Original ARPACK internal vector.
    elt_t   *workv;     // Original ARPACK internal vector.
    elt_t   *V;         // Arnoldi basis / Schur vectors.

    // a.3) Pure output variables.

    integer nconv;      // Number of "converged" Ritz values.

    const char *error;
};

}

#endif /* !TENSOR_ARPACK_D_H */