// SPDX-License-Identifier: Apache-2.0
// 
// Copyright 2008-2016 Conrad Sanderson (https://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
// https://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 glue_atan2
//! @{



template<typename T1, typename T2>
inline
void
glue_atan2::apply(Mat<typename T1::elem_type>& out, const Glue<T1, T2, glue_atan2>& expr)
  {
  arma_debug_sigprint();
  
  typedef typename T1::elem_type eT;
  
  const Proxy<T1> P1(expr.A);
  const Proxy<T2> P2(expr.B);
  
  arma_assert_same_size(P1, P2, "atan2()");
  
  const bool bad_alias = ( (Proxy<T1>::has_subview && P1.is_alias(out)) || (Proxy<T2>::has_subview && P2.is_alias(out)) );
  
  if(bad_alias == false)
    {
    glue_atan2::apply_noalias(out, P1, P2);
    }
  else
    {
    Mat<eT> tmp;
    
    glue_atan2::apply_noalias(tmp, P1, P2);
    
    out.steal_mem(tmp);
    }
  }



template<typename T1, typename T2>
inline
void
glue_atan2::apply_noalias(Mat<typename T1::elem_type>& out, const Proxy<T1>& P1, const Proxy<T2>& P2)
  {
  arma_debug_sigprint();
  
  typedef typename T1::elem_type eT;
  
  const uword n_rows = P1.get_n_rows();
  const uword n_cols = P1.get_n_cols();
  const uword n_elem = P1.get_n_elem();
  
  out.set_size(n_rows, n_cols);
  
  eT* out_mem = out.memptr();
  
  const     bool use_mp = arma_config::openmp && mp_gate<eT, (Proxy<T1>::use_mp || Proxy<T2>::use_mp)>::eval(n_elem);
  constexpr bool use_at = Proxy<T1>::use_at || Proxy<T2>::use_at;
  
  if(use_at == false)
    {
    typename Proxy<T1>::ea_type eaP1 = P1.get_ea();
    typename Proxy<T2>::ea_type eaP2 = P2.get_ea();
    
    if(use_mp)
      {
      #if defined(ARMA_USE_OPENMP)
        {
        const int n_threads = mp_thread_limit::get();
        #pragma omp parallel for schedule(static) num_threads(n_threads)
        for(uword i=0; i<n_elem; ++i)
          {
          out_mem[i] = std::atan2( eaP1[i], eaP2[i] );
          }
        }
      #endif
      }
    else
      {
      for(uword i=0; i<n_elem; ++i)
        {
        out_mem[i] = std::atan2( eaP1[i], eaP2[i] );
        }
      }
    }
  else
    {
    if(use_mp)
      {
      const unwrap<typename Proxy<T1>::stored_type> U1(P1.Q);
      const unwrap<typename Proxy<T2>::stored_type> U2(P2.Q);
      
      out = arma::atan2(U1.M, U2.M);
      }
    else
      {
      for(uword col=0; col < n_cols; ++col)
      for(uword row=0; row < n_rows; ++row)
        {
        *out_mem = std::atan2( P1.at(row,col), P2.at(row,col) );
        out_mem++;
        }
      }
    }
  }



template<typename T1, typename T2>
inline
void
glue_atan2::apply(Cube<typename T1::elem_type>& out, const GlueCube<T1, T2, glue_atan2>& expr)
  {
  arma_debug_sigprint();
  
  typedef typename T1::elem_type eT;
  
  const ProxyCube<T1> P1(expr.A);
  const ProxyCube<T2> P2(expr.B);
  
  arma_assert_same_size(P1, P2, "atan2()");
  
  const bool bad_alias = ( (ProxyCube<T1>::has_subview && P1.is_alias(out)) || (ProxyCube<T2>::has_subview && P2.is_alias(out)) );
  
  if(bad_alias == false)
    {
    glue_atan2::apply_noalias(out, P1, P2);
    }
  else
    {
    Cube<eT> tmp;
    
    glue_atan2::apply_noalias(tmp, P1, P2);
    
    out.steal_mem(tmp);
    }
  }



template<typename T1, typename T2>
inline
void
glue_atan2::apply_noalias(Cube<typename T1::elem_type>& out, const ProxyCube<T1>& P1, const ProxyCube<T2>& P2)
  {
  arma_debug_sigprint();
  
  typedef typename T1::elem_type eT;
  
  const uword n_rows   = P1.get_n_rows();
  const uword n_cols   = P1.get_n_cols();
  const uword n_slices = P1.get_n_slices();
  const uword n_elem   = P1.get_n_elem();
  
  out.set_size(n_rows, n_cols, n_slices);
  
  eT* out_mem = out.memptr();
  
  const     bool use_mp = arma_config::openmp && mp_gate<eT, (ProxyCube<T1>::use_mp || ProxyCube<T2>::use_mp)>::eval(n_elem);
  constexpr bool use_at = ProxyCube<T1>::use_at || ProxyCube<T2>::use_at;
  
  if(use_at == false)
    {
    typename ProxyCube<T1>::ea_type eaP1 = P1.get_ea();
    typename ProxyCube<T2>::ea_type eaP2 = P2.get_ea();
    
    if(use_mp)
      {
      #if defined(ARMA_USE_OPENMP)
        {
        const int n_threads = mp_thread_limit::get();
        #pragma omp parallel for schedule(static) num_threads(n_threads)
        for(uword i=0; i<n_elem; ++i)
          {
          out_mem[i] = std::atan2( eaP1[i], eaP2[i] );
          }
        }
      #endif
      }
    else
      {
      for(uword i=0; i<n_elem; ++i)
        {
        out_mem[i] = std::atan2( eaP1[i], eaP2[i] );
        }
      }
    }
  else
    {
    if(use_mp)
      {
      const unwrap_cube<typename ProxyCube<T1>::stored_type> U1(P1.Q);
      const unwrap_cube<typename ProxyCube<T2>::stored_type> U2(P2.Q);
      
      out = arma::atan2(U1.M, U2.M);
      }
    else
      {
      for(uword slice=0; slice < n_slices; ++slice)
      for(uword   col=0;   col < n_cols;   ++col  )
      for(uword   row=0;   row < n_rows;   ++row  )
        {
        *out_mem = std::atan2( P1.at(row,col,slice), P2.at(row,col,slice) );
        out_mem++;
        }
      }
    }
  }



//! @}
