// 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_diagvec
//! @{

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

  typedef typename T1::elem_type eT;

  const Proxy<T1> P(X.m);

  if (P.is_alias(out) == false) {
    op_diagvec::apply_proxy(out, P);
  } else {
    Mat<eT> tmp;

    op_diagvec::apply_proxy(tmp, P);

    out.steal_mem(tmp);
  }
}

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

  typedef typename T1::elem_type eT;

  const uword n_rows = P.get_n_rows();
  const uword n_cols = P.get_n_cols();

  const uword len = (std::min)(n_rows, n_cols);

  out.set_size(len, 1);

  eT* out_mem = out.memptr();

  uword i, j;
  for (i = 0, j = 1; j < len; i += 2, j += 2) {
    const eT tmp_i = P.at(i, i);
    const eT tmp_j = P.at(j, j);

    out_mem[i] = tmp_i;
    out_mem[j] = tmp_j;
  }

  if (i < len) {
    out_mem[i] = P.at(i, i);
  }
}

template <typename T1, typename T2>
inline void op_diagvec::apply(
    Mat<typename T1::elem_type>& actual_out,
    const Op<Glue<T1, T2, glue_times>, op_diagvec>& X,
    const typename arma_not_cx<typename T1::elem_type>::result* junk) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename T1::elem_type eT;

  const partial_unwrap<T1> UA(X.m.A);
  const partial_unwrap<T2> UB(X.m.B);

  const typename partial_unwrap<T1>::stored_type& A = UA.M;
  const typename partial_unwrap<T2>::stored_type& B = UB.M;

  arma_conform_assert_trans_mul_size<partial_unwrap<T1>::do_trans,
                                     partial_unwrap<T2>::do_trans>(
      A.n_rows, A.n_cols, B.n_rows, B.n_cols, "matrix multiplication");

  if ((A.n_elem == 0) || (B.n_elem == 0)) {
    actual_out.reset();
    return;
  }

  constexpr bool use_alpha = partial_unwrap<T1>::do_times || partial_unwrap<T2>::do_times;
  const eT alpha = use_alpha ? (UA.get_val() * UB.get_val()) : eT(0);

  const bool is_alias = (UA.is_alias(actual_out) || UB.is_alias(actual_out));

  Mat<eT> tmp;
  Mat<eT>& out = (is_alias) ? tmp : actual_out;

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

  const uword B_n_rows = B.n_rows;
  const uword B_n_cols = B.n_cols;

  if ((partial_unwrap<T1>::do_trans == false) &&
      (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = false; trans_B = false;");

    const uword N = (std::min)(A_n_rows, B_n_cols);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      eT acc1 = eT(0);
      eT acc2 = eT(0);

      const eT* B_colptr = B.colptr(k);

      // condition: A_n_cols = B_n_rows

      uword j;

      for (j = 1; j < A_n_cols; j += 2) {
        const uword i = (j - 1);

        const eT tmp_i = B_colptr[i];
        const eT tmp_j = B_colptr[j];

        acc1 += A.at(k, i) * tmp_i;
        acc2 += A.at(k, j) * tmp_j;
      }

      const uword i = (j - 1);

      if (i < A_n_cols) {
        acc1 += A.at(k, i) * B_colptr[i];
      }

      const eT acc = acc1 + acc2;

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = true; trans_B = false;");

    const uword N = (std::min)(A_n_cols, B_n_cols);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      const eT* A_colptr = A.colptr(k);
      const eT* B_colptr = B.colptr(k);

      // condition: A_n_rows = B_n_rows

      const eT acc = op_dot::direct_dot(A_n_rows, A_colptr, B_colptr);

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == false) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = false; trans_B = true;");

    const uword N = (std::min)(A_n_rows, B_n_rows);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      eT acc = eT(0);

      // condition: A_n_cols = B_n_cols

      for (uword i = 0; i < A_n_cols; ++i) {
        acc += A.at(k, i) * B.at(k, i);
      }

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = true; trans_B = true;");

    const uword N = (std::min)(A_n_cols, B_n_rows);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      eT acc = eT(0);

      const eT* A_colptr = A.colptr(k);

      // condition: A_n_rows = B_n_cols

      for (uword i = 0; i < A_n_rows; ++i) {
        acc += A_colptr[i] * B.at(k, i);
      }

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  }

  if (is_alias) {
    actual_out.steal_mem(tmp);
  }
}

template <typename T1, typename T2>
inline void op_diagvec::apply(
    Mat<typename T1::elem_type>& actual_out,
    const Op<Glue<T1, T2, glue_times>, op_diagvec>& X,
    const typename arma_cx_only<typename T1::elem_type>::result* junk) {
  arma_debug_sigprint();
  arma_ignore(junk);

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

  const partial_unwrap<T1> UA(X.m.A);
  const partial_unwrap<T2> UB(X.m.B);

  const typename partial_unwrap<T1>::stored_type& A = UA.M;
  const typename partial_unwrap<T2>::stored_type& B = UB.M;

  arma_conform_assert_trans_mul_size<partial_unwrap<T1>::do_trans,
                                     partial_unwrap<T2>::do_trans>(
      A.n_rows, A.n_cols, B.n_rows, B.n_cols, "matrix multiplication");

  if ((A.n_elem == 0) || (B.n_elem == 0)) {
    actual_out.reset();
    return;
  }

  constexpr bool use_alpha = partial_unwrap<T1>::do_times || partial_unwrap<T2>::do_times;
  const eT alpha = use_alpha ? (UA.get_val() * UB.get_val()) : eT(0);

  const bool is_alias = (UA.is_alias(actual_out) || UB.is_alias(actual_out));

  Mat<eT> tmp;
  Mat<eT>& out = (is_alias) ? tmp : actual_out;

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

  const uword B_n_rows = B.n_rows;
  const uword B_n_cols = B.n_cols;

  if ((partial_unwrap<T1>::do_trans == false) &&
      (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = false; trans_B = false;");

    const uword N = (std::min)(A_n_rows, B_n_cols);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      const eT* B_colptr = B.colptr(k);

      // condition: A_n_cols = B_n_rows

      for (uword i = 0; i < A_n_cols; ++i) {
        // acc += A.at(k, i) * B_colptr[i];

        const std::complex<T>& xx = A.at(k, i);
        const std::complex<T>& yy = B_colptr[i];

        const T a = xx.real();
        const T b = xx.imag();

        const T c = yy.real();
        const T d = yy.imag();

        acc_real += (a * c) - (b * d);
        acc_imag += (a * d) + (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == false)) {
    arma_debug_print("trans_A = true; trans_B = false;");

    const uword N = (std::min)(A_n_cols, B_n_cols);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      const eT* A_colptr = A.colptr(k);
      const eT* B_colptr = B.colptr(k);

      // condition: A_n_rows = B_n_rows

      for (uword i = 0; i < A_n_rows; ++i) {
        // acc += std::conj(A_colptr[i]) * B_colptr[i];

        const std::complex<T>& xx = A_colptr[i];
        const std::complex<T>& yy = B_colptr[i];

        const T a = xx.real();
        const T b = xx.imag();

        const T c = yy.real();
        const T d = yy.imag();

        // take into account the complex conjugate of xx

        acc_real += (a * c) + (b * d);
        acc_imag += (a * d) - (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == false) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = false; trans_B = true;");

    const uword N = (std::min)(A_n_rows, B_n_rows);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      // condition: A_n_cols = B_n_cols

      for (uword i = 0; i < A_n_cols; ++i) {
        // acc += A.at(k,i) * std::conj(B.at(k,i));

        const std::complex<T>& xx = A.at(k, i);
        const std::complex<T>& yy = B.at(k, i);

        const T a = xx.real();
        const T b = xx.imag();

        const T c = yy.real();
        const T d = -yy.imag();  // take the conjugate

        acc_real += (a * c) - (b * d);
        acc_imag += (a * d) + (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  } else if ((partial_unwrap<T1>::do_trans == true) &&
             (partial_unwrap<T2>::do_trans == true)) {
    arma_debug_print("trans_A = true; trans_B = true;");

    const uword N = (std::min)(A_n_cols, B_n_rows);

    out.set_size(N, 1);

    eT* out_mem = out.memptr();

    for (uword k = 0; k < N; ++k) {
      T acc_real = T(0);
      T acc_imag = T(0);

      const eT* A_colptr = A.colptr(k);

      // condition: A_n_rows = B_n_cols

      for (uword i = 0; i < A_n_rows; ++i) {
        // acc += std::conj(A_colptr[i]) * std::conj(B.at(k,i));

        const std::complex<T>& xx = A_colptr[i];
        const std::complex<T>& yy = B.at(k, i);

        const T a = xx.real();
        const T b = -xx.imag();  // take the conjugate

        const T c = yy.real();
        const T d = -yy.imag();  // take the conjugate

        acc_real += (a * c) - (b * d);
        acc_imag += (a * d) + (b * c);
      }

      const eT acc = std::complex<T>(acc_real, acc_imag);

      out_mem[k] = (use_alpha) ? eT(alpha * acc) : eT(acc);
    }
  }

  if (is_alias) {
    actual_out.steal_mem(tmp);
  }
}

//
//
//

template <typename T1>
inline void op_diagvec2::apply(Mat<typename T1::elem_type>& out,
                               const Op<T1, op_diagvec2>& X) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const uword a = X.aux_uword_a;
  const uword b = X.aux_uword_b;

  const uword row_offset = (b > 0) ? a : 0;
  const uword col_offset = (b == 0) ? a : 0;

  const Proxy<T1> P(X.m);

  if (P.is_alias(out) == false) {
    op_diagvec2::apply_proxy(out, P, row_offset, col_offset);
  } else {
    Mat<eT> tmp;

    op_diagvec2::apply_proxy(tmp, P, row_offset, col_offset);

    out.steal_mem(tmp);
  }
}

template <typename T1>
inline void op_diagvec2::apply_proxy(Mat<typename T1::elem_type>& out, const Proxy<T1>& P,
                                     const uword row_offset, const uword col_offset) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const uword n_rows = P.get_n_rows();
  const uword n_cols = P.get_n_cols();

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

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

  out.set_size(len, 1);

  eT* out_mem = out.memptr();

  uword i, j;
  for (i = 0, j = 1; j < len; i += 2, j += 2) {
    const eT tmp_i = P.at(i + row_offset, i + col_offset);
    const eT tmp_j = P.at(j + row_offset, j + col_offset);

    out_mem[i] = tmp_i;
    out_mem[j] = tmp_j;
  }

  if (i < len) {
    out_mem[i] = P.at(i + row_offset, i + col_offset);
  }
}

//! @}
