include/armadillo_bits/operator_div.hpp

// 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_extra_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_extra_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_extra_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_extra_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_extra_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_extra_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_extra_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_extra_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_debug_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_extra_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_extra_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_debug_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_extra_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_extra_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_extra_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_extra_debug_sigprint();

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


//! @}