// 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 diagview
//! @{


template<typename eT>
inline
diagview<eT>::~diagview()
  {
  arma_debug_sigprint_this(this);
  }



template<typename eT>
arma_inline
diagview<eT>::diagview(const Mat<eT>& in_m, const uword in_row_offset, const uword in_col_offset, const uword in_len)
  : m         (in_m         )
  , row_offset(in_row_offset)
  , col_offset(in_col_offset)
  , n_rows    (in_len       )
  , n_elem    (in_len       )
  {
  arma_debug_sigprint_this(this);
  }



template<typename eT>
inline
diagview<eT>::diagview(const diagview<eT>& in)
  : m         (in.m         )
  , row_offset(in.row_offset)
  , col_offset(in.col_offset)
  , n_rows    (in.n_rows    )
  , n_elem    (in.n_elem    )
  {
  arma_debug_sigprint(arma_str::format("this: %x; in: %x") % this % &in);
  }



template<typename eT>
inline
diagview<eT>::diagview(diagview<eT>&& in)
  : m         (in.m         )
  , row_offset(in.row_offset)
  , col_offset(in.col_offset)
  , n_rows    (in.n_rows    )
  , n_elem    (in.n_elem    )
  {
  arma_debug_sigprint(arma_str::format("this: %x; in: %x") % this % &in);
  
  // for paranoia
  
  access::rw(in.row_offset) = 0;
  access::rw(in.col_offset) = 0;
  access::rw(in.n_rows    ) = 0;
  access::rw(in.n_elem    ) = 0;
  }



//! set a diagonal of our matrix using a diagonal from a foreign matrix
template<typename eT>
inline
void
diagview<eT>::operator= (const diagview<eT>& x)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  arma_conform_check( (d.n_elem != x.n_elem), "diagview: diagonals have incompatible lengths" );
  
        Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  const Mat<eT>& x_m = x.m;
  
  if(&d_m != &x_m)
    {
    const uword d_n_elem     = d.n_elem;
    const uword d_row_offset = d.row_offset;
    const uword d_col_offset = d.col_offset;
    
    const uword x_row_offset = x.row_offset;
    const uword x_col_offset = x.col_offset;
    
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = x_m.at(ii + x_row_offset, ii + x_col_offset);
      const eT tmp_j = x_m.at(jj + x_row_offset, jj + x_col_offset);
      
      d_m.at(ii + d_row_offset, ii + d_col_offset) = tmp_i;
      d_m.at(jj + d_row_offset, jj + d_col_offset) = tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at(ii + d_row_offset, ii + d_col_offset) = x_m.at(ii + x_row_offset, ii + x_col_offset);
      }
    }
  else
    {
    const Mat<eT> tmp = x;
    
    (*this).operator=(tmp);
    }
  }



template<typename eT>
inline
void
diagview<eT>::operator+=(const eT val)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
  
  uword ii,jj;
  
  for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) += val;
    d_m.at( jj + d_row_offset,  jj + d_col_offset) += val;
    }
  
  if(ii < d_n_elem)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) += val;
    }
  }



template<typename eT>
inline
void
diagview<eT>::operator-=(const eT val)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
  
  uword ii,jj;
  
  for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) -= val;
    d_m.at( jj + d_row_offset,  jj + d_col_offset) -= val;
    }
  
  if(ii < d_n_elem)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) -= val;
    }
  }



template<typename eT>
inline
void
diagview<eT>::operator*=(const eT val)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
  
  uword ii,jj;
  
  for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) *= val;
    d_m.at( jj + d_row_offset,  jj + d_col_offset) *= val;
    }
  
  if(ii < d_n_elem)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) *= val;
    }
  }



template<typename eT>
inline
void
diagview<eT>::operator/=(const eT val)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
  
  uword ii,jj;
  
  for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) /= val;
    d_m.at( jj + d_row_offset,  jj + d_col_offset) /= val;
    }
  
  if(ii < d_n_elem)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) /= val;
    }
  }



//! set a diagonal of our matrix using data from a foreign object
template<typename eT>
template<typename T1>
inline
void
diagview<eT>::operator= (const Base<eT,T1>& o)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
    
  const Proxy<T1> P( o.get_ref() );
  
  arma_conform_check
    (
    ( (d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1)) ),
    "diagview: given object has incompatible size"
    );
  
  constexpr bool is_gen_zeros = (is_same_type< T1, Gen<Mat<eT>, gen_zeros> >::yes) || (is_same_type< T1, Gen<Col<eT>, gen_zeros> >::yes);
  constexpr bool is_gen_ones  = (is_same_type< T1, Gen<Mat<eT>, gen_ones > >::yes) || (is_same_type< T1, Gen<Col<eT>, gen_ones > >::yes);
  
  if(is_gen_zeros)  { d.zeros(); return; }
  if(is_gen_ones )  { d.ones();  return; }
  
  const bool have_alias = P.is_alias(d_m);
  
  if(have_alias)  { arma_debug_print("aliasing detected"); }
  
  if( (is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at) || (have_alias) )
    {
    const unwrap_check<typename Proxy<T1>::stored_type> tmp(P.Q, have_alias);
    const Mat<eT>& x = tmp.M;
    
    const eT* x_mem = x.memptr();
    
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = x_mem[ii];
      const eT tmp_j = x_mem[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) = tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) = tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) = x_mem[ii];
      }
    }
  else
    {
    typename Proxy<T1>::ea_type Pea = P.get_ea();
      
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = Pea[ii];
      const eT tmp_j = Pea[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) = tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) = tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) = Pea[ii];
      }
    }
  }



template<typename eT>
template<typename T1>
inline
void
diagview<eT>::operator+=(const Base<eT,T1>& o)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
    
  const Proxy<T1> P( o.get_ref() );
  
  arma_conform_check
    (
    ( (d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1)) ),
    "diagview: given object has incompatible size"
    );
  
  const bool have_alias = P.is_alias(d_m);
  
  if(have_alias)  { arma_debug_print("aliasing detected"); }
  
  if( (is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at) || (have_alias) )
    {
    const unwrap_check<typename Proxy<T1>::stored_type> tmp(P.Q, have_alias);
    const Mat<eT>& x = tmp.M;
    
    const eT* x_mem = x.memptr();
    
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = x_mem[ii];
      const eT tmp_j = x_mem[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) += tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) += tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) += x_mem[ii];
      }
    }
  else
    {
    typename Proxy<T1>::ea_type Pea = P.get_ea();
      
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = Pea[ii];
      const eT tmp_j = Pea[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) += tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) += tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) += Pea[ii];
      }
    }
  }



template<typename eT>
template<typename T1>
inline
void
diagview<eT>::operator-=(const Base<eT,T1>& o)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
    
  const Proxy<T1> P( o.get_ref() );
  
  arma_conform_check
    (
    ( (d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1)) ),
    "diagview: given object has incompatible size"
    );
  
  const bool have_alias = P.is_alias(d_m);
  
  if(have_alias)  { arma_debug_print("aliasing detected"); }
  
  if( (is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at) || (have_alias) )
    {
    const unwrap_check<typename Proxy<T1>::stored_type> tmp(P.Q, have_alias);
    const Mat<eT>& x = tmp.M;
    
    const eT* x_mem = x.memptr();
    
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = x_mem[ii];
      const eT tmp_j = x_mem[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) -= tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) -= tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) -= x_mem[ii];
      }
    }
  else
    {
    typename Proxy<T1>::ea_type Pea = P.get_ea();
      
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = Pea[ii];
      const eT tmp_j = Pea[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) -= tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) -= tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) -= Pea[ii];
      }
    }
  }



template<typename eT>
template<typename T1>
inline
void
diagview<eT>::operator%=(const Base<eT,T1>& o)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
    
  const Proxy<T1> P( o.get_ref() );
  
  arma_conform_check
    (
    ( (d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1)) ),
    "diagview: given object has incompatible size"
    );
  
  const bool have_alias = P.is_alias(d_m);
  
  if(have_alias)  { arma_debug_print("aliasing detected"); }
  
  if( (is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at) || (have_alias) )
    {
    const unwrap_check<typename Proxy<T1>::stored_type> tmp(P.Q, have_alias);
    const Mat<eT>& x = tmp.M;
    
    const eT* x_mem = x.memptr();
    
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = x_mem[ii];
      const eT tmp_j = x_mem[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) *= tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) *= tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) *= x_mem[ii];
      }
    }
  else
    {
    typename Proxy<T1>::ea_type Pea = P.get_ea();
      
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = Pea[ii];
      const eT tmp_j = Pea[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) *= tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) *= tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) *= Pea[ii];
      }
    }
  }



template<typename eT>
template<typename T1>
inline
void
diagview<eT>::operator/=(const Base<eT,T1>& o)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
    
  const Proxy<T1> P( o.get_ref() );
  
  arma_conform_check
    (
    ( (d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1)) ),
    "diagview: given object has incompatible size"
    );
  
  const bool have_alias = P.is_alias(d_m);
  
  if(have_alias)  { arma_debug_print("aliasing detected"); }
  
  if( (is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at) || (have_alias) )
    {
    const unwrap_check<typename Proxy<T1>::stored_type> tmp(P.Q, have_alias);
    const Mat<eT>& x = tmp.M;
    
    const eT* x_mem = x.memptr();
    
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = x_mem[ii];
      const eT tmp_j = x_mem[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) /= tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) /= tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) /= x_mem[ii];
      }
    }
  else
    {
    typename Proxy<T1>::ea_type Pea = P.get_ea();
      
    uword ii,jj;
    for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
      {
      const eT tmp_i = Pea[ii];
      const eT tmp_j = Pea[jj];
      
      d_m.at( ii + d_row_offset,  ii + d_col_offset) /= tmp_i;
      d_m.at( jj + d_row_offset,  jj + d_col_offset) /= tmp_j;
      }
    
    if(ii < d_n_elem)
      {
      d_m.at( ii + d_row_offset,  ii + d_col_offset) /= Pea[ii];
      }
    }
  }



//! extract a diagonal and store it as a column vector
template<typename eT>
inline
void
diagview<eT>::extract(Mat<eT>& out, const diagview<eT>& in)
  {
  arma_debug_sigprint();
  
  // NOTE: we're assuming that the matrix has already been set to the correct size and there is no aliasing;
  // size setting and alias checking is done by either the Mat constructor or operator=()
  
  const Mat<eT>& in_m = in.m;
  
  const uword in_n_elem     = in.n_elem;
  const uword in_row_offset = in.row_offset;
  const uword in_col_offset = in.col_offset;
  
  eT* out_mem = out.memptr();
  
  uword i,j;
  for(i=0, j=1; j < in_n_elem; i+=2, j+=2)
    {
    const eT tmp_i = in_m.at( i + in_row_offset, i + in_col_offset );
    const eT tmp_j = in_m.at( j + in_row_offset, j + in_col_offset );
    
    out_mem[i] = tmp_i;
    out_mem[j] = tmp_j;
    }
  
  if(i < in_n_elem)
    {
    out_mem[i] = in_m.at( i + in_row_offset, i + in_col_offset );
    }
  }



//! X += Y.diag()
template<typename eT>
inline
void
diagview<eT>::plus_inplace(Mat<eT>& out, const diagview<eT>& in)
  {
  arma_debug_sigprint();
  
  arma_conform_assert_same_size(out.n_rows, out.n_cols, in.n_rows, in.n_cols, "addition");
  
  const Mat<eT>& in_m = in.m;
  
  const uword in_n_elem     = in.n_elem;
  const uword in_row_offset = in.row_offset;
  const uword in_col_offset = in.col_offset;
  
  eT* out_mem = out.memptr();
  
  uword i,j;
  for(i=0, j=1; j < in_n_elem; i+=2, j+=2)
    {
    const eT tmp_i = in_m.at( i + in_row_offset, i + in_col_offset );
    const eT tmp_j = in_m.at( j + in_row_offset, j + in_col_offset );
    
    out_mem[i] += tmp_i;
    out_mem[j] += tmp_j;
    }
  
  if(i < in_n_elem)
    {
    out_mem[i] += in_m.at( i + in_row_offset, i + in_col_offset );
    }
  }



//! X -= Y.diag()
template<typename eT>
inline
void
diagview<eT>::minus_inplace(Mat<eT>& out, const diagview<eT>& in)
  {
  arma_debug_sigprint();
  
  arma_conform_assert_same_size(out.n_rows, out.n_cols, in.n_rows, in.n_cols, "subtraction");
  
  const Mat<eT>& in_m = in.m;
  
  const uword in_n_elem     = in.n_elem;
  const uword in_row_offset = in.row_offset;
  const uword in_col_offset = in.col_offset;
  
  eT* out_mem = out.memptr();
  
  uword i,j;
  for(i=0, j=1; j < in_n_elem; i+=2, j+=2)
    {
    const eT tmp_i = in_m.at( i + in_row_offset, i + in_col_offset );
    const eT tmp_j = in_m.at( j + in_row_offset, j + in_col_offset );
    
    out_mem[i] -= tmp_i;
    out_mem[j] -= tmp_j;
    }
  
  if(i < in_n_elem)
    {
    out_mem[i] -= in_m.at( i + in_row_offset, i + in_col_offset );
    }
  }



//! X %= Y.diag()
template<typename eT>
inline
void
diagview<eT>::schur_inplace(Mat<eT>& out, const diagview<eT>& in)
  {
  arma_debug_sigprint();
  
  arma_conform_assert_same_size(out.n_rows, out.n_cols, in.n_rows, in.n_cols, "element-wise multiplication");
  
  const Mat<eT>& in_m = in.m;
  
  const uword in_n_elem     = in.n_elem;
  const uword in_row_offset = in.row_offset;
  const uword in_col_offset = in.col_offset;
  
  eT* out_mem = out.memptr();
  
  uword i,j;
  for(i=0, j=1; j < in_n_elem; i+=2, j+=2)
    {
    const eT tmp_i = in_m.at( i + in_row_offset, i + in_col_offset );
    const eT tmp_j = in_m.at( j + in_row_offset, j + in_col_offset );
    
    out_mem[i] *= tmp_i;
    out_mem[j] *= tmp_j;
    }
  
  if(i < in_n_elem)
    {
    out_mem[i] *= in_m.at( i + in_row_offset, i + in_col_offset );
    }
  }



//! X /= Y.diag()
template<typename eT>
inline
void
diagview<eT>::div_inplace(Mat<eT>& out, const diagview<eT>& in)
  {
  arma_debug_sigprint();
  
  arma_conform_assert_same_size(out.n_rows, out.n_cols, in.n_rows, in.n_cols, "element-wise division");
  
  const Mat<eT>& in_m = in.m;
  
  const uword in_n_elem     = in.n_elem;
  const uword in_row_offset = in.row_offset;
  const uword in_col_offset = in.col_offset;
  
  eT* out_mem = out.memptr();
  
  uword i,j;
  for(i=0, j=1; j < in_n_elem; i+=2, j+=2)
    {
    const eT tmp_i = in_m.at( i + in_row_offset, i + in_col_offset );
    const eT tmp_j = in_m.at( j + in_row_offset, j + in_col_offset );
    
    out_mem[i] /= tmp_i;
    out_mem[j] /= tmp_j;
    }
  
  if(i < in_n_elem)
    {
    out_mem[i] /= in_m.at( i + in_row_offset, i + in_col_offset );
    }
  }



template<typename eT>
arma_inline
eT
diagview<eT>::at_alt(const uword ii) const
  {
  return m.at(ii+row_offset, ii+col_offset);
  }



template<typename eT>
arma_inline
eT&
diagview<eT>::operator[](const uword ii)
  {
  return (const_cast< Mat<eT>& >(m)).at(ii+row_offset, ii+col_offset);
  }



template<typename eT>
arma_inline
eT
diagview<eT>::operator[](const uword ii) const
  {
  return m.at(ii+row_offset, ii+col_offset);
  }



template<typename eT>
arma_inline
eT&
diagview<eT>::at(const uword ii)
  {
  return (const_cast< Mat<eT>& >(m)).at(ii+row_offset, ii+col_offset);
  }



template<typename eT>
arma_inline
eT
diagview<eT>::at(const uword ii) const
  {
  return m.at(ii+row_offset, ii+col_offset);
  }



template<typename eT>
arma_inline
eT&
diagview<eT>::operator()(const uword ii)
  {
  arma_conform_check_bounds( (ii >= n_elem), "diagview::operator(): out of bounds" );
  
  return (const_cast< Mat<eT>& >(m)).at(ii+row_offset, ii+col_offset);
  }



template<typename eT>
arma_inline
eT
diagview<eT>::operator()(const uword ii) const
  {
  arma_conform_check_bounds( (ii >= n_elem), "diagview::operator(): out of bounds" );
  
  return m.at(ii+row_offset, ii+col_offset);
  }



template<typename eT>
arma_inline
eT&
diagview<eT>::at(const uword row, const uword)
  {
  return (const_cast< Mat<eT>& >(m)).at(row+row_offset, row+col_offset);
  }



template<typename eT>
arma_inline
eT
diagview<eT>::at(const uword row, const uword) const
  {
  return m.at(row+row_offset, row+col_offset);
  }



template<typename eT>
arma_inline
eT&
diagview<eT>::operator()(const uword row, const uword col)
  {
  arma_conform_check_bounds( ((row >= n_elem) || (col > 0)), "diagview::operator(): out of bounds" );
  
  return (const_cast< Mat<eT>& >(m)).at(row+row_offset, row+col_offset);
  }



template<typename eT>
arma_inline
eT
diagview<eT>::operator()(const uword row, const uword col) const
  {
  arma_conform_check_bounds( ((row >= n_elem) || (col > 0)), "diagview::operator(): out of bounds" );
  
  return m.at(row+row_offset, row+col_offset);
  }



template<typename eT>
inline
void
diagview<eT>::replace(const eT old_val, const eT new_val)
  {
  arma_debug_sigprint();
  
  Mat<eT>& x = const_cast< Mat<eT>& >(m);
  
  const uword local_n_elem = n_elem;
  
  if(arma_isnan(old_val))
    {
    for(uword ii=0; ii < local_n_elem; ++ii)
      {
      eT& val = x.at(ii+row_offset, ii+col_offset);
      
      val = (arma_isnan(val)) ? new_val : val;
      }
    }
  else
    {
    for(uword ii=0; ii < local_n_elem; ++ii)
      {
      eT& val = x.at(ii+row_offset, ii+col_offset);
      
      val = (val == old_val) ? new_val : val;
      }
    }
  }



template<typename eT>
inline
void
diagview<eT>::clean(const typename get_pod_type<eT>::result threshold)
  {
  arma_debug_sigprint();
  
  Mat<eT> tmp(*this);
  
  tmp.clean(threshold);
  
  (*this).operator=(tmp);
  }



template<typename eT>
inline
void
diagview<eT>::clamp(const eT min_val, const eT max_val)
  {
  arma_debug_sigprint();
  
  Mat<eT> tmp(*this);
  
  tmp.clamp(min_val, max_val);
  
  (*this).operator=(tmp);
  }



template<typename eT>
inline
void
diagview<eT>::fill(const eT val)
  {
  arma_debug_sigprint();
  
  diagview<eT>& d = *this;
  
  Mat<eT>& d_m = const_cast< Mat<eT>& >(d.m);
  
  const uword d_n_elem     = d.n_elem;
  const uword d_row_offset = d.row_offset;
  const uword d_col_offset = d.col_offset;
  
  uword ii,jj;
  
  for(ii=0, jj=1; jj < d_n_elem; ii+=2, jj+=2)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) = val;
    d_m.at( jj + d_row_offset,  jj + d_col_offset) = val;
    }
  
  if(ii < d_n_elem)
    {
    d_m.at( ii + d_row_offset,  ii + d_col_offset) = val;
    }
  }



template<typename eT>
inline
void
diagview<eT>::zeros()
  {
  arma_debug_sigprint();
  
  (*this).fill(eT(0));
  }



template<typename eT>
inline
void
diagview<eT>::ones()
  {
  arma_debug_sigprint();
  
  (*this).fill(eT(1));
  }



template<typename eT>
inline
void
diagview<eT>::randu()
  {
  arma_debug_sigprint();
  
  Mat<eT>& x = const_cast< Mat<eT>& >(m);
  
  const uword local_n_elem = n_elem;
  
  Col<eT> tmp(local_n_elem, arma_nozeros_indicator());
  
  tmp.randu();
  
  for(uword ii=0; ii < local_n_elem; ++ii)
    {
    x.at(ii+row_offset, ii+col_offset) = tmp[ii];
    }
  }



template<typename eT>
inline
void
diagview<eT>::randn()
  {
  arma_debug_sigprint();
  
  Mat<eT>& x = const_cast< Mat<eT>& >(m);
  
  const uword local_n_elem = n_elem;
  
  Col<eT> tmp(local_n_elem, arma_nozeros_indicator());
  
  tmp.randn();
  
  for(uword ii=0; ii < local_n_elem; ++ii)
    {
    x.at(ii+row_offset, ii+col_offset) = tmp[ii];
    }
  }



template<typename eT>
template<typename eT2>
inline
bool
diagview<eT>::is_alias(const Mat<eT2>& X) const
  {
  arma_debug_sigprint();
  
  return m.is_alias(X);
  }



//! @}