// 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_lu
//! @{

//! immediate lower upper decomposition, permutation info is embedded into L (similar to
//! Matlab/Octave)
template <typename T1>
inline bool lu(
    Mat<typename T1::elem_type>& L, Mat<typename T1::elem_type>& U,
    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);

  arma_conform_check((&L == &U), "lu(): L and U are the same object");

  const bool status = auxlib::lu(L, U, X);

  if (status == false) {
    L.soft_reset();
    U.soft_reset();
    arma_warn(3, "lu(): decomposition failed");
  }

  return status;
}

//! immediate lower upper decomposition, also providing the permutation matrix
template <typename T1>
inline bool lu(
    Mat<typename T1::elem_type>& L, Mat<typename T1::elem_type>& U,
    Mat<typename T1::elem_type>& P, 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);

  arma_conform_check(((&L == &U) || (&L == &P) || (&U == &P)),
                     "lu(): two or more output objects are the same object");

  const bool status = auxlib::lu(L, U, P, X);

  if (status == false) {
    L.soft_reset();
    U.soft_reset();
    P.soft_reset();
    arma_warn(3, "lu(): decomposition failed");
  }

  return status;
}

//! @}
