// 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_svd
//! @{

template <typename T1>
inline bool svd(
    Col<typename T1::pod_type>& S, const Base<typename T1::elem_type, T1>& X,
    const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename T1::elem_type eT;

  Mat<eT> A(X.get_ref());

  const bool status = auxlib::svd_dc(S, A);

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

  return status;
}

template <typename T1>
arma_warn_unused inline Col<typename T1::pod_type> svd(
    const Base<typename T1::elem_type, T1>& X,
    const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename T1::elem_type eT;
  typedef typename T1::pod_type T;

  Col<T> out;

  Mat<eT> A(X.get_ref());

  const bool status = auxlib::svd_dc(out, A);

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

  return out;
}

template <typename T1>
inline bool svd(
    Mat<typename T1::elem_type>& U, Col<typename T1::pod_type>& S,
    Mat<typename T1::elem_type>& V, const Base<typename T1::elem_type, T1>& X,
    const char* method = "dc",
    const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename T1::elem_type eT;

  arma_conform_check(
      (((void*)(&U) == (void*)(&S)) || (&U == &V) || ((void*)(&S) == (void*)(&V))),
      "svd(): two or more output objects are the same object");

  const char sig = (method != nullptr) ? method[0] : char(0);

  arma_conform_check(((sig != 's') && (sig != 'd')), "svd(): unknown method specified");

  Mat<eT> A(X.get_ref());

  const bool status = (sig == 'd') ? auxlib::svd_dc(U, S, V, A) : auxlib::svd(U, S, V, A);

  if (status == false) {
    U.soft_reset();
    S.soft_reset();
    V.soft_reset();
    arma_warn(3, "svd(): decomposition failed");
  }

  return status;
}

template <typename T1>
inline bool svd_econ(
    Mat<typename T1::elem_type>& U, Col<typename T1::pod_type>& S,
    Mat<typename T1::elem_type>& V, const Base<typename T1::elem_type, T1>& X,
    const char mode, const char* method = "dc",
    const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename T1::elem_type eT;

  arma_conform_check(
      (((void*)(&U) == (void*)(&S)) || (&U == &V) || ((void*)(&S) == (void*)(&V))),
      "svd_econ(): two or more output objects are the same object");

  arma_conform_check(((mode != 'l') && (mode != 'r') && (mode != 'b')),
                     "svd_econ(): parameter 'mode' is incorrect");

  const char sig = (method != nullptr) ? method[0] : char(0);

  arma_conform_check(((sig != 's') && (sig != 'd')),
                     "svd_econ(): unknown method specified");

  Mat<eT> A(X.get_ref());

  const bool status = ((mode == 'b') && (sig == 'd'))
                          ? auxlib::svd_dc_econ(U, S, V, A)
                          : auxlib::svd_econ(U, S, V, A, mode);

  if (status == false) {
    U.soft_reset();
    S.soft_reset();
    V.soft_reset();
    arma_warn(3, "svd_econ(): decomposition failed");
  }

  return status;
}

template <typename T1>
inline bool svd_econ(
    Mat<typename T1::elem_type>& U, Col<typename T1::pod_type>& S,
    Mat<typename T1::elem_type>& V, const Base<typename T1::elem_type, T1>& X,
    const char* mode = "both", const char* method = "dc",
    const typename arma_blas_type_only<typename T1::elem_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  return svd_econ(U, S, V, X, ((mode != nullptr) ? mode[0] : char(0)), method);
}

//! @}
