// 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 operator_div
//! @{

//! Base / scalar
template <typename T1>
arma_inline typename enable_if2<is_arma_type<T1>::value,
                                const eOp<T1, eop_scalar_div_post> >::result
operator/(const T1& X, const typename T1::elem_type k) {
  arma_debug_sigprint();

  return eOp<T1, eop_scalar_div_post>(X, k);
}

//! scalar / Base
template <typename T1>
arma_inline typename enable_if2<is_arma_type<T1>::value,
                                const eOp<T1, eop_scalar_div_pre> >::result
operator/(const typename T1::elem_type k, const T1& X) {
  arma_debug_sigprint();

  return eOp<T1, eop_scalar_div_pre>(X, k);
}

//! complex scalar / non-complex Base
template <typename T1>
arma_inline
    typename enable_if2<(is_arma_type<T1>::value && is_cx<typename T1::elem_type>::no),
                        const mtOp<typename std::complex<typename T1::pod_type>, T1,
                                   op_cx_scalar_div_pre> >::result
    operator/(const std::complex<typename T1::pod_type>& k, const T1& X) {
  arma_debug_sigprint();

  return mtOp<typename std::complex<typename T1::pod_type>, T1, op_cx_scalar_div_pre>(
      'j', X, k);
}

//! non-complex Base / complex scalar
template <typename T1>
arma_inline
    typename enable_if2<(is_arma_type<T1>::value && is_cx<typename T1::elem_type>::no),
                        const mtOp<typename std::complex<typename T1::pod_type>, T1,
                                   op_cx_scalar_div_post> >::result
    operator/(const T1& X, const std::complex<typename T1::pod_type>& k) {
  arma_debug_sigprint();

  return mtOp<typename std::complex<typename T1::pod_type>, T1, op_cx_scalar_div_post>(
      'j', X, k);
}

//! element-wise division of Base objects with same element type
template <typename T1, typename T2>
arma_inline typename enable_if2<
    (is_arma_type<T1>::value && is_arma_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::value),
    const eGlue<T1, T2, eglue_div> >::result
operator/(const T1& X, const T2& Y) {
  arma_debug_sigprint();

  return eGlue<T1, T2, eglue_div>(X, Y);
}

//! element-wise division of Base objects with different element types
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_type<T1>::value && is_arma_type<T2>::value &&
     (is_same_type<typename T1::elem_type, typename T2::elem_type>::no)),
    const mtGlue<
        typename promote_type<typename T1::elem_type, typename T2::elem_type>::result, T1,
        T2, glue_mixed_div> >::result
operator/(const T1& X, const T2& Y) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT1;
  typedef typename T2::elem_type eT2;

  typedef typename promote_type<eT1, eT2>::result out_eT;

  promote_type<eT1, eT2>::check();

  return mtGlue<out_eT, T1, T2, glue_mixed_div>(X, Y);
}

//! element-wise division of sparse matrix by scalar
template <typename T1>
inline typename enable_if2<is_arma_sparse_type<T1>::value,
                           SpMat<typename T1::elem_type> >::result
operator/(const T1& X, const typename T1::elem_type y) {
  arma_debug_sigprint();

  SpMat<typename T1::elem_type> result(X);

  result /= y;

  return result;
}

//! element-wise division of one sparse and one dense object
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_sparse_type<T1>::value && is_arma_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::value),
    SpMat<typename T1::elem_type> >::result
operator/(const T1& x, const T2& y) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const SpProxy<T1> pa(x);
  const Proxy<T2> pb(y);

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

  arma_conform_assert_same_size(n_rows, n_cols, pb.get_n_rows(), pb.get_n_cols(),
                                "element-wise division");

  uword new_n_nonzero = 0;

  for (uword col = 0; col < n_cols; ++col)
    for (uword row = 0; row < n_rows; ++row) {
      const eT val = pa.at(row, col) / pb.at(row, col);

      if (val != eT(0)) {
        ++new_n_nonzero;
      }
    }

  SpMat<eT> result(arma_reserve_indicator(), n_rows, n_cols, new_n_nonzero);

  uword cur_pos = 0;

  for (uword col = 0; col < n_cols; ++col)
    for (uword row = 0; row < n_rows; ++row) {
      const eT val = pa.at(row, col) / pb.at(row, col);

      if (val != eT(0)) {
        access::rw(result.values[cur_pos]) = val;
        access::rw(result.row_indices[cur_pos]) = row;
        ++access::rw(result.col_ptrs[col + 1]);
        ++cur_pos;
      }
    }

  // Fix column pointers
  for (uword col = 1; col <= result.n_cols; ++col) {
    access::rw(result.col_ptrs[col]) += result.col_ptrs[col - 1];
  }

  return result;
}

//! optimization: element-wise division of sparse / (sparse +/- scalar)
template <typename T1, typename T2, typename op_type>
inline typename enable_if2<
    (is_arma_sparse_type<T1>::value && is_arma_sparse_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::yes &&
     (is_same_type<op_type, op_sp_plus>::value ||
      is_same_type<op_type, op_sp_minus_pre>::value ||
      is_same_type<op_type, op_sp_minus_post>::value)),
    SpMat<typename T1::elem_type> >::result
operator/(const T1& x, const SpToDOp<T2, op_type>& y) {
  arma_debug_sigprint();

  SpMat<typename T1::elem_type> out;

  op_type::apply_inside_div(out, x, y);

  return out;
}

//! element-wise division of one dense and one sparse object
template <typename T1, typename T2>
inline typename enable_if2<
    (is_arma_type<T1>::value && is_arma_sparse_type<T2>::value &&
     is_same_type<typename T1::elem_type, typename T2::elem_type>::value),
    Mat<typename T1::elem_type> >::result
operator/(const T1& x, const T2& y) {
  arma_debug_sigprint();

  typedef typename T1::elem_type eT;

  const Proxy<T1> pa(x);
  const SpProxy<T2> pb(y);

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

  arma_conform_assert_same_size(n_rows, n_cols, pb.get_n_rows(), pb.get_n_cols(),
                                "element-wise division");

  Mat<eT> result(n_rows, n_cols, arma_nozeros_indicator());

  for (uword col = 0; col < n_cols; ++col)
    for (uword row = 0; row < n_rows; ++row) {
      result.at(row, col) = pa.at(row, col) / pb.at(row, col);
    }

  return result;
}

template <typename parent, unsigned int mode, typename T2>
arma_inline Mat<typename parent::elem_type> operator/(
    const subview_each1<parent, mode>& X, const Base<typename parent::elem_type, T2>& Y) {
  arma_debug_sigprint();

  return subview_each1_aux::operator_div(X, Y.get_ref());
}

template <typename T1, typename parent, unsigned int mode>
arma_inline Mat<typename parent::elem_type> operator/(
    const Base<typename parent::elem_type, T1>& X, const subview_each1<parent, mode>& Y) {
  arma_debug_sigprint();

  return subview_each1_aux::operator_div(X.get_ref(), Y);
}

template <typename parent, unsigned int mode, typename TB, typename T2>
arma_inline Mat<typename parent::elem_type> operator/(
    const subview_each2<parent, mode, TB>& X,
    const Base<typename parent::elem_type, T2>& Y) {
  arma_debug_sigprint();

  return subview_each2_aux::operator_div(X, Y.get_ref());
}

template <typename T1, typename parent, unsigned int mode, typename TB>
arma_inline Mat<typename parent::elem_type> operator/(
    const Base<typename parent::elem_type, T1>& X,
    const subview_each2<parent, mode, TB>& Y) {
  arma_debug_sigprint();

  return subview_each2_aux::operator_div(X.get_ref(), Y);
}

//! @}
