// 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 op_trimat
//! @{

template <typename eT>
inline void op_trimat::fill_zeros(Mat<eT>& out, const bool upper) {
  arma_debug_sigprint();

  const uword N = out.n_rows;

  if (upper) {
    // upper triangular: set all elements below the diagonal to zero

    for (uword i = 0; i < N; ++i) {
      eT* data = out.colptr(i);

      arrayops::fill_zeros(&data[i + 1], (N - (i + 1)));
    }
  } else {
    // lower triangular: set all elements above the diagonal to zero

    for (uword i = 1; i < N; ++i) {
      eT* data = out.colptr(i);

      arrayops::fill_zeros(data, i);
    }
  }
}

template <typename T1>
inline void op_trimat::apply(Mat<typename T1::elem_type>& out,
                             const Op<T1, op_trimat>& in) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const bool upper = (in.aux_uword_a == 0);

  // allow detection of in-place operation
  if (is_Mat<T1>::value || (arma_config::openmp && Proxy<T1>::use_mp)) {
    const unwrap<T1> U(in.m);

    op_trimat::apply_unwrap(out, U.M, upper);
  } else {
    const Proxy<T1> P(in.m);

    const bool is_alias = P.is_alias(out);

    if (is_Mat<typename Proxy<T1>::stored_type>::value) {
      const quasi_unwrap<typename Proxy<T1>::stored_type> U(P.Q);

      if (is_alias) {
        Mat<eT> tmp;

        op_trimat::apply_unwrap(tmp, U.M, upper);

        out.steal_mem(tmp);
      } else {
        op_trimat::apply_unwrap(out, U.M, upper);
      }
    } else {
      if (is_alias) {
        Mat<eT> tmp;

        op_trimat::apply_proxy(tmp, P, upper);

        out.steal_mem(tmp);
      } else {
        op_trimat::apply_proxy(out, P, upper);
      }
    }
  }
}

template <typename eT>
inline void op_trimat::apply_unwrap(Mat<eT>& out, const Mat<eT>& A, const bool upper) {
  arma_debug_sigprint();

  arma_conform_check((A.is_square() == false),
                     "trimatu()/trimatl(): given matrix must be square sized");

  if (&out != &A) {
    out.copy_size(A);

    const uword N = A.n_rows;

    if (upper) {
      // upper triangular: copy the diagonal and the elements above the diagonal
      for (uword i = 0; i < N; ++i) {
        const eT* A_data = A.colptr(i);
        eT* out_data = out.colptr(i);

        arrayops::copy(out_data, A_data, i + 1);
      }
    } else {
      // lower triangular: copy the diagonal and the elements below the diagonal
      for (uword i = 0; i < N; ++i) {
        const eT* A_data = A.colptr(i);
        eT* out_data = out.colptr(i);

        arrayops::copy(&out_data[i], &A_data[i], N - i);
      }
    }
  }

  op_trimat::fill_zeros(out, upper);
}

template <typename T1>
inline void op_trimat::apply_proxy(Mat<typename T1::elem_type>& out, const Proxy<T1>& P,
                                   const bool upper) {
  arma_debug_sigprint();

  arma_conform_check((P.get_n_rows() != P.get_n_cols()),
                     "trimatu()/trimatl(): given matrix must be square sized");

  const uword N = P.get_n_rows();

  out.set_size(N, N);

  if (upper) {
    for (uword j = 0; j < N; ++j)
      for (uword i = 0; i < (j + 1); ++i) {
        out.at(i, j) = P.at(i, j);
      }
  } else {
    for (uword j = 0; j < N; ++j)
      for (uword i = j; i < N; ++i) {
        out.at(i, j) = P.at(i, j);
      }
  }

  op_trimat::fill_zeros(out, upper);
}

//

template <typename T1>
inline void op_trimatu_ext::apply(Mat<typename T1::elem_type>& out,
                                  const Op<T1, op_trimatu_ext>& in) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const unwrap<T1> tmp(in.m);
  const Mat<eT>& A = tmp.M;

  arma_conform_check((A.is_square() == false),
                     "trimatu(): given matrix must be square sized");

  const uword row_offset = in.aux_uword_a;
  const uword col_offset = in.aux_uword_b;

  const uword n_rows = A.n_rows;
  const uword n_cols = A.n_cols;

  arma_conform_check_bounds(((row_offset > 0) && (row_offset >= n_rows)) ||
                                ((col_offset > 0) && (col_offset >= n_cols)),
                            "trimatu(): requested diagonal is out of bounds");

  if (&out != &A) {
    out.copy_size(A);

    const uword N = (std::min)(n_rows - row_offset, n_cols - col_offset);

    for (uword i = 0; i < n_cols; ++i) {
      const uword col = i + col_offset;

      if (i < N) {
        const uword end_row = i + row_offset;

        for (uword row = 0; row <= end_row; ++row) {
          out.at(row, col) = A.at(row, col);
        }
      } else {
        if (col < n_cols) {
          arrayops::copy(out.colptr(col), A.colptr(col), n_rows);
        }
      }
    }
  }

  op_trimatu_ext::fill_zeros(out, row_offset, col_offset);
}

template <typename eT>
inline void op_trimatu_ext::fill_zeros(Mat<eT>& out, const uword row_offset,
                                       const uword col_offset) {
  arma_debug_sigprint();

  const uword n_rows = out.n_rows;
  const uword n_cols = out.n_cols;

  const uword N = (std::min)(n_rows - row_offset, n_cols - col_offset);

  for (uword col = 0; col < col_offset; ++col) {
    arrayops::fill_zeros(out.colptr(col), n_rows);
  }

  for (uword i = 0; i < N; ++i) {
    const uword start_row = i + row_offset + 1;
    const uword col = i + col_offset;

    for (uword row = start_row; row < n_rows; ++row) {
      out.at(row, col) = eT(0);
    }
  }
}

//

template <typename T1>
inline void op_trimatl_ext::apply(Mat<typename T1::elem_type>& out,
                                  const Op<T1, op_trimatl_ext>& in) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const unwrap<T1> tmp(in.m);
  const Mat<eT>& A = tmp.M;

  arma_conform_check((A.is_square() == false),
                     "trimatl(): given matrix must be square sized");

  const uword row_offset = in.aux_uword_a;
  const uword col_offset = in.aux_uword_b;

  const uword n_rows = A.n_rows;
  const uword n_cols = A.n_cols;

  arma_conform_check_bounds(((row_offset > 0) && (row_offset >= n_rows)) ||
                                ((col_offset > 0) && (col_offset >= n_cols)),
                            "trimatl(): requested diagonal is out of bounds");

  if (&out != &A) {
    out.copy_size(A);

    const uword N = (std::min)(n_rows - row_offset, n_cols - col_offset);

    for (uword col = 0; col < col_offset; ++col) {
      arrayops::copy(out.colptr(col), A.colptr(col), n_rows);
    }

    for (uword i = 0; i < N; ++i) {
      const uword start_row = i + row_offset;
      const uword col = i + col_offset;

      for (uword row = start_row; row < n_rows; ++row) {
        out.at(row, col) = A.at(row, col);
      }
    }
  }

  op_trimatl_ext::fill_zeros(out, row_offset, col_offset);
}

template <typename eT>
inline void op_trimatl_ext::fill_zeros(Mat<eT>& out, const uword row_offset,
                                       const uword col_offset) {
  arma_debug_sigprint();

  const uword n_rows = out.n_rows;
  const uword n_cols = out.n_cols;

  const uword N = (std::min)(n_rows - row_offset, n_cols - col_offset);

  for (uword i = 0; i < n_cols; ++i) {
    const uword col = i + col_offset;

    if (i < N) {
      const uword end_row = i + row_offset;

      for (uword row = 0; row < end_row; ++row) {
        out.at(row, col) = eT(0);
      }
    } else {
      if (col < n_cols) {
        arrayops::fill_zeros(out.colptr(col), n_rows);
      }
    }
  }
}

//! @}
