// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------

//! \addtogroup fn_eigs_sym
//! @{

//! eigenvalues of symmetric real sparse matrix X
template <typename T1>
arma_warn_unused inline typename enable_if2<is_real<typename T1::elem_type>::value,
                                            Col<typename T1::pod_type> >::result
eigs_sym(const SpBase<typename T1::elem_type, T1>& X, const uword n_eigvals,
         const char* form = "lm", const eigs_opts opts = eigs_opts()) {
  arma_debug_sigprint();

  Mat<typename T1::elem_type> eigvec;
  Col<typename T1::pod_type> eigval;

  sp_auxlib::form_type form_val = sp_auxlib::interpret_form_str(form);

  const bool status = sp_auxlib::eigs_sym(eigval, eigvec, X, n_eigvals, form_val, opts);

  if (status == false) {
    eigval.soft_reset();
    arma_stop_runtime_error("eigs_sym(): decomposition failed");
  }

  return eigval;
}

//! this form is deprecated; use eigs_sym(X, n_eigvals, form, opts) instead
template <typename T1>
arma_deprecated inline typename enable_if2<is_real<typename T1::elem_type>::value,
                                           Col<typename T1::pod_type> >::result
eigs_sym(const SpBase<typename T1::elem_type, T1>& X, const uword n_eigvals,
         const char* form, const typename T1::elem_type tol) {
  arma_debug_sigprint();

  eigs_opts opts;
  opts.tol = tol;

  return eigs_sym(X, n_eigvals, form, opts);
}

template <typename T1>
arma_warn_unused inline typename enable_if2<is_real<typename T1::elem_type>::value,
                                            Col<typename T1::pod_type> >::result
eigs_sym(const SpBase<typename T1::elem_type, T1>& X, const uword n_eigvals,
         const double sigma, const eigs_opts opts = eigs_opts()) {
  arma_debug_sigprint();

  typedef typename T1::pod_type T;

  Mat<typename T1::elem_type> eigvec;
  Col<typename T1::pod_type> eigval;

  const bool status = sp_auxlib::eigs_sym(eigval, eigvec, X, n_eigvals, T(sigma), opts);

  if (status == false) {
    eigval.soft_reset();
    arma_stop_runtime_error("eigs_sym(): decomposition failed");
  }

  return eigval;
}

//! eigenvalues of symmetric real sparse matrix X
template <typename T1>
inline typename enable_if2<is_real<typename T1::elem_type>::value, bool>::result eigs_sym(
    Col<typename T1::pod_type>& eigval, const SpBase<typename T1::elem_type, T1>& X,
    const uword n_eigvals, const char* form = "lm", const eigs_opts opts = eigs_opts()) {
  arma_debug_sigprint();

  Mat<typename T1::elem_type> eigvec;

  sp_auxlib::form_type form_val = sp_auxlib::interpret_form_str(form);

  const bool status = sp_auxlib::eigs_sym(eigval, eigvec, X, n_eigvals, form_val, opts);

  if (status == false) {
    eigval.soft_reset();
    arma_warn(3, "eigs_sym(): decomposition failed");
  }

  return status;
}

//! this form is deprecated; use eigs_sym(eigval, X, n_eigvals, form, opts) instead
template <typename T1>
arma_deprecated inline
    typename enable_if2<is_real<typename T1::elem_type>::value, bool>::result
    eigs_sym(Col<typename T1::pod_type>& eigval,
             const SpBase<typename T1::elem_type, T1>& X, const uword n_eigvals,
             const char* form, const typename T1::elem_type tol) {
  arma_debug_sigprint();

  eigs_opts opts;
  opts.tol = tol;

  return eigs_sym(eigval, X, n_eigvals, form, opts);
}

template <typename T1>
inline typename enable_if2<is_real<typename T1::elem_type>::value, bool>::result eigs_sym(
    Col<typename T1::pod_type>& eigval, const SpBase<typename T1::elem_type, T1>& X,
    const uword n_eigvals, const double sigma, const eigs_opts opts = eigs_opts()) {
  arma_debug_sigprint();

  typedef typename T1::pod_type T;

  Mat<typename T1::elem_type> eigvec;

  const bool status = sp_auxlib::eigs_sym(eigval, eigvec, X, n_eigvals, T(sigma), opts);

  if (status == false) {
    eigval.soft_reset();
    arma_warn(3, "eigs_sym(): decomposition failed");
  }

  return status;
}

//! eigenvalues and eigenvectors of symmetric real sparse matrix X
template <typename T1>
inline typename enable_if2<is_real<typename T1::elem_type>::value, bool>::result eigs_sym(
    Col<typename T1::pod_type>& eigval, Mat<typename T1::elem_type>& eigvec,
    const SpBase<typename T1::elem_type, T1>& X, const uword n_eigvals,
    const char* form = "lm", const eigs_opts opts = eigs_opts()) {
  arma_debug_sigprint();

  arma_conform_check(void_ptr(&eigval) == void_ptr(&eigvec),
                     "eigs_sym(): parameter 'eigval' is an alias of parameter 'eigvec'");

  sp_auxlib::form_type form_val = sp_auxlib::interpret_form_str(form);

  const bool status = sp_auxlib::eigs_sym(eigval, eigvec, X, n_eigvals, form_val, opts);

  if (status == false) {
    eigval.soft_reset();
    eigvec.soft_reset();
    arma_warn(3, "eigs_sym(): decomposition failed");
  }

  return status;
}

//! this form is deprecated; use eigs_sym(eigval, eigvec, X, n_eigvals, form, opts)
//! instead
template <typename T1>
arma_deprecated inline
    typename enable_if2<is_real<typename T1::elem_type>::value, bool>::result
    eigs_sym(Col<typename T1::pod_type>& eigval, Mat<typename T1::elem_type>& eigvec,
             const SpBase<typename T1::elem_type, T1>& X, const uword n_eigvals,
             const char* form, const typename T1::elem_type tol) {
  arma_debug_sigprint();

  eigs_opts opts;
  opts.tol = tol;

  return eigs_sym(eigval, eigvec, X, n_eigvals, form, opts);
}

template <typename T1>
inline typename enable_if2<is_real<typename T1::elem_type>::value, bool>::result eigs_sym(
    Col<typename T1::pod_type>& eigval, Mat<typename T1::elem_type>& eigvec,
    const SpBase<typename T1::elem_type, T1>& X, const uword n_eigvals,
    const double sigma, const eigs_opts opts = eigs_opts()) {
  arma_debug_sigprint();

  typedef typename T1::pod_type T;

  arma_conform_check(void_ptr(&eigval) == void_ptr(&eigvec),
                     "eigs_sym(): parameter 'eigval' is an alias of parameter 'eigvec'");

  const bool status = sp_auxlib::eigs_sym(eigval, eigvec, X, n_eigvals, T(sigma), opts);

  if (status == false) {
    eigval.soft_reset();
    eigvec.soft_reset();
    arma_warn(3, "eigs_sym(): decomposition failed");
  }

  return status;
}

//! @}
