// 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 spdiagview
//! @{

template <typename eT>
inline spdiagview<eT>::~spdiagview() {
  arma_extra_debug_sigprint();
}

template <typename eT>
arma_inline spdiagview<eT>::spdiagview(const SpMat<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_extra_debug_sigprint();
}

//! set a diagonal of our matrix using a diagonal from a foreign matrix
template <typename eT>
inline void spdiagview<eT>::operator=(const spdiagview<eT>& x) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  arma_debug_check((d.n_elem != x.n_elem),
                   "spdiagview: diagonals have incompatible lengths");

  SpMat<eT>& d_m = const_cast<SpMat<eT>&>(d.m);
  const SpMat<eT>& x_m = x.m;

  if ((&d_m == &x_m) || ((d.row_offset == 0) && (d.col_offset == 0))) {
    const Mat<eT> tmp(x);

    (*this).operator=(tmp);
  } else {
    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;

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) =
          x_m.at(i + x_row_offset, i + x_col_offset);
    }
  }
}

template <typename eT>
inline void spdiagview<eT>::operator+=(const eT val) {
  arma_extra_debug_sigprint();

  if (val == eT(0)) {
    return;
  }

  SpMat<eT>& t_m = const_cast<SpMat<eT>&>(m);

  const uword t_n_elem = n_elem;
  const uword t_row_offset = row_offset;
  const uword t_col_offset = col_offset;

  for (uword i = 0; i < t_n_elem; ++i) {
    t_m.at(i + t_row_offset, i + t_col_offset) += val;
  }
}

template <typename eT>
inline void spdiagview<eT>::operator-=(const eT val) {
  arma_extra_debug_sigprint();

  if (val == eT(0)) {
    return;
  }

  SpMat<eT>& t_m = const_cast<SpMat<eT>&>(m);

  const uword t_n_elem = n_elem;
  const uword t_row_offset = row_offset;
  const uword t_col_offset = col_offset;

  for (uword i = 0; i < t_n_elem; ++i) {
    t_m.at(i + t_row_offset, i + t_col_offset) -= val;
  }
}

template <typename eT>
inline void spdiagview<eT>::operator*=(const eT val) {
  arma_extra_debug_sigprint();

  if (val == eT(0)) {
    (*this).zeros();
    return;
  }

  SpMat<eT>& t_m = const_cast<SpMat<eT>&>(m);

  const uword t_n_elem = n_elem;
  const uword t_row_offset = row_offset;
  const uword t_col_offset = col_offset;

  for (uword i = 0; i < t_n_elem; ++i) {
    t_m.at(i + t_row_offset, i + t_col_offset) *= val;
  }
}

template <typename eT>
inline void spdiagview<eT>::operator/=(const eT val) {
  arma_extra_debug_sigprint();

  SpMat<eT>& t_m = const_cast<SpMat<eT>&>(m);

  const uword t_n_elem = n_elem;
  const uword t_row_offset = row_offset;
  const uword t_col_offset = col_offset;

  for (uword i = 0; i < t_n_elem; ++i) {
    t_m.at(i + t_row_offset, i + t_col_offset) /= val;
  }
}

//! set a diagonal of our matrix using data from a foreign object
template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator=(const Base<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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;

  if (is_same_type<T1, Gen<Col<eT>, gen_zeros> >::yes) {
    const Proxy<T1> P(o.get_ref());

    arma_debug_check((d_n_elem != P.get_n_elem()),
                     "spdiagview: given object has incompatible size");

    (*this).zeros();

    return;
  }

  if (is_same_type<T1, Gen<Col<eT>, gen_ones> >::yes) {
    const Proxy<T1> P(o.get_ref());

    arma_debug_check((d_n_elem != P.get_n_elem()),
                     "spdiagview: given object has incompatible size");

    (*this).ones();

    return;
  }

  const quasi_unwrap<T1> U(o.get_ref());
  const Mat<eT>& x = U.M;

  const eT* x_mem = x.memptr();

  arma_debug_check(((d_n_elem != x.n_elem) || ((x.n_rows != 1) && (x.n_cols != 1))),
                   "spdiagview: given object has incompatible size");

  if ((d_row_offset == 0) && (d_col_offset == 0)) {
    SpMat<eT> tmp1;

    tmp1.eye(d_m.n_rows, d_m.n_cols);

    bool has_zero = false;

    for (uword i = 0; i < d_n_elem; ++i) {
      const eT val = x_mem[i];

      access::rw(tmp1.values[i]) = val;

      if (val == eT(0)) {
        has_zero = true;
      }
    }

    if (has_zero) {
      tmp1.remove_zeros();
    }

    if (tmp1.n_nonzero == 0) {
      (*this).zeros();
      return;
    }

    SpMat<eT> tmp2;

    spglue_merge::diagview_merge(tmp2, d_m, tmp1);

    d_m.steal_mem(tmp2);
  } else {
    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) = x_mem[i];
    }
  }
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator+=(const Base<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if ((is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at)) {
    const unwrap<typename Proxy<T1>::stored_type> tmp(P.Q);
    const Mat<eT>& x = tmp.M;

    const eT* x_mem = x.memptr();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) += x_mem[i];
    }
  } else {
    typename Proxy<T1>::ea_type Pea = P.get_ea();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) += Pea[i];
    }
  }
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator-=(const Base<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if ((is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at)) {
    const unwrap<typename Proxy<T1>::stored_type> tmp(P.Q);
    const Mat<eT>& x = tmp.M;

    const eT* x_mem = x.memptr();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) -= x_mem[i];
    }
  } else {
    typename Proxy<T1>::ea_type Pea = P.get_ea();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) -= Pea[i];
    }
  }
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator%=(const Base<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if ((is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at)) {
    const unwrap<typename Proxy<T1>::stored_type> tmp(P.Q);
    const Mat<eT>& x = tmp.M;

    const eT* x_mem = x.memptr();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) *= x_mem[i];
    }
  } else {
    typename Proxy<T1>::ea_type Pea = P.get_ea();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) *= Pea[i];
    }
  }
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator/=(const Base<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if ((is_Mat<typename Proxy<T1>::stored_type>::value) || (Proxy<T1>::use_at)) {
    const unwrap<typename Proxy<T1>::stored_type> tmp(P.Q);
    const Mat<eT>& x = tmp.M;

    const eT* x_mem = x.memptr();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) /= x_mem[i];
    }
  } else {
    typename Proxy<T1>::ea_type Pea = P.get_ea();

    for (uword i = 0; i < d_n_elem; ++i) {
      d_m.at(i + d_row_offset, i + d_col_offset) /= Pea[i];
    }
  }
}

//! set a diagonal of our matrix using data from a foreign object
template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator=(const SpBase<eT, T1>& o) {
  arma_extra_debug_sigprint();

  const unwrap_spmat<T1> U(o.get_ref());
  const SpMat<eT>& x = U.M;

  arma_debug_check(((n_elem != x.n_elem) || ((x.n_rows != 1) && (x.n_cols != 1))),
                   "spdiagview: given object has incompatible size");

  const Mat<eT> tmp(x);

  (*this).operator=(tmp);
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator+=(const SpBase<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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 SpProxy<T1> P(o.get_ref());

  arma_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if (SpProxy<T1>::use_iterator || P.is_alias(d_m)) {
    const SpMat<eT> tmp(P.Q);

    if (tmp.n_cols == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) += tmp.at(i, 0);
      }
    } else if (tmp.n_rows == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) += tmp.at(0, i);
      }
    }
  } else {
    if (P.get_n_cols() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) += P.at(i, 0);
      }
    } else if (P.get_n_rows() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) += P.at(0, i);
      }
    }
  }
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator-=(const SpBase<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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 SpProxy<T1> P(o.get_ref());

  arma_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if (SpProxy<T1>::use_iterator || P.is_alias(d_m)) {
    const SpMat<eT> tmp(P.Q);

    if (tmp.n_cols == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) -= tmp.at(i, 0);
      }
    } else if (tmp.n_rows == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) -= tmp.at(0, i);
      }
    }
  } else {
    if (P.get_n_cols() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) -= P.at(i, 0);
      }
    } else if (P.get_n_rows() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) -= P.at(0, i);
      }
    }
  }
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator%=(const SpBase<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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 SpProxy<T1> P(o.get_ref());

  arma_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if (SpProxy<T1>::use_iterator || P.is_alias(d_m)) {
    const SpMat<eT> tmp(P.Q);

    if (tmp.n_cols == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) *= tmp.at(i, 0);
      }
    } else if (tmp.n_rows == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) *= tmp.at(0, i);
      }
    }
  } else {
    if (P.get_n_cols() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) *= P.at(i, 0);
      }
    } else if (P.get_n_rows() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) *= P.at(0, i);
      }
    }
  }
}

template <typename eT>
template <typename T1>
inline void spdiagview<eT>::operator/=(const SpBase<eT, T1>& o) {
  arma_extra_debug_sigprint();

  spdiagview<eT>& d = *this;

  SpMat<eT>& d_m = const_cast<SpMat<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 SpProxy<T1> P(o.get_ref());

  arma_debug_check(
      ((d_n_elem != P.get_n_elem()) || ((P.get_n_rows() != 1) && (P.get_n_cols() != 1))),
      "spdiagview: given object has incompatible size");

  if (SpProxy<T1>::use_iterator || P.is_alias(d_m)) {
    const SpMat<eT> tmp(P.Q);

    if (tmp.n_cols == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) /= tmp.at(i, 0);
      }
    } else if (tmp.n_rows == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) /= tmp.at(0, i);
      }
    }
  } else {
    if (P.get_n_cols() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) /= P.at(i, 0);
      }
    } else if (P.get_n_rows() == 1) {
      for (uword i = 0; i < d_n_elem; ++i) {
        d_m.at(i + d_row_offset, i + d_col_offset) /= P.at(0, i);
      }
    }
  }
}

template <typename eT>
inline void spdiagview<eT>::extract(SpMat<eT>& out, const spdiagview<eT>& d) {
  arma_extra_debug_sigprint();

  const SpMat<eT>& d_m = 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;

  Col<eT> cache(d_n_elem, arma_nozeros_indicator());
  eT* cache_mem = cache.memptr();

  uword d_n_nonzero = 0;

  for (uword i = 0; i < d_n_elem; ++i) {
    const eT val = d_m.at(i + d_row_offset, i + d_col_offset);

    cache_mem[i] = val;

    d_n_nonzero += (val != eT(0)) ? uword(1) : uword(0);
  }

  out.reserve(d_n_elem, 1, d_n_nonzero);

  uword count = 0;
  for (uword i = 0; i < d_n_elem; ++i) {
    const eT val = cache_mem[i];

    if (val != eT(0)) {
      access::rw(out.row_indices[count]) = i;
      access::rw(out.values[count]) = val;
      ++count;
    }
  }

  access::rw(out.col_ptrs[0]) = 0;
  access::rw(out.col_ptrs[1]) = d_n_nonzero;
}

//! extract a diagonal and store it as a dense column vector
template <typename eT>
inline void spdiagview<eT>::extract(Mat<eT>& out, const spdiagview<eT>& in) {
  arma_extra_debug_sigprint();

  // NOTE: we're assuming that the 'out' matrix has already been set to the correct size;
  // size setting is done by either the Mat contructor or Mat::operator=()

  const SpMat<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();

  for (uword i = 0; i < in_n_elem; ++i) {
    out_mem[i] = in_m.at(i + in_row_offset, i + in_col_offset);
  }
}

template <typename eT>
inline SpMat_MapMat_val<eT> spdiagview<eT>::operator[](const uword i) {
  return (const_cast<SpMat<eT>&>(m)).at(i + row_offset, i + col_offset);
}

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

template <typename eT>
inline SpMat_MapMat_val<eT> spdiagview<eT>::at(const uword i) {
  return (const_cast<SpMat<eT>&>(m)).at(i + row_offset, i + col_offset);
}

template <typename eT>
inline eT spdiagview<eT>::at(const uword i) const {
  return m.at(i + row_offset, i + col_offset);
}

template <typename eT>
inline SpMat_MapMat_val<eT> spdiagview<eT>::operator()(const uword i) {
  arma_debug_check_bounds((i >= n_elem), "spdiagview::operator(): out of bounds");

  return (const_cast<SpMat<eT>&>(m)).at(i + row_offset, i + col_offset);
}

template <typename eT>
inline eT spdiagview<eT>::operator()(const uword i) const {
  arma_debug_check_bounds((i >= n_elem), "spdiagview::operator(): out of bounds");

  return m.at(i + row_offset, i + col_offset);
}

template <typename eT>
inline SpMat_MapMat_val<eT> spdiagview<eT>::at(const uword row, const uword) {
  return (const_cast<SpMat<eT>&>(m)).at(row + row_offset, row + col_offset);
}

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

template <typename eT>
inline SpMat_MapMat_val<eT> spdiagview<eT>::operator()(const uword row, const uword col) {
  arma_debug_check_bounds(((row >= n_elem) || (col > 0)),
                          "spdiagview::operator(): out of bounds");

  return (const_cast<SpMat<eT>&>(m)).at(row + row_offset, row + col_offset);
}

template <typename eT>
inline eT spdiagview<eT>::operator()(const uword row, const uword col) const {
  arma_debug_check_bounds(((row >= n_elem) || (col > 0)),
                          "spdiagview::operator(): out of bounds");

  return m.at(row + row_offset, row + col_offset);
}

template <typename eT>
inline void spdiagview<eT>::replace(const eT old_val, const eT new_val) {
  arma_extra_debug_sigprint();

  if (old_val == eT(0)) {
    arma_debug_warn_level(1,
                          "spdiagview::replace(): replacement not done, as old_val = 0");
  } else {
    Mat<eT> tmp(*this);

    tmp.replace(old_val, new_val);

    (*this).operator=(tmp);
  }
}

template <typename eT>
inline void spdiagview<eT>::clean(const typename get_pod_type<eT>::result threshold) {
  arma_extra_debug_sigprint();

  Mat<eT> tmp(*this);

  tmp.clean(threshold);

  (*this).operator=(tmp);
}

template <typename eT>
inline void spdiagview<eT>::clamp(const eT min_val, const eT max_val) {
  arma_extra_debug_sigprint();

  SpMat<eT> tmp(*this);

  tmp.clamp(min_val, max_val);

  (*this).operator=(tmp);
}

template <typename eT>
inline void spdiagview<eT>::fill(const eT val) {
  arma_extra_debug_sigprint();

  if ((row_offset == 0) && (col_offset == 0) && (m.sync_state != 1)) {
    if (val == eT(0)) {
      SpMat<eT> tmp(arma_reserve_indicator(), m.n_rows, m.n_cols,
                    m.n_nonzero);  // worst case scenario

      typename SpMat<eT>::const_iterator it = m.begin();
      typename SpMat<eT>::const_iterator it_end = m.end();

      uword count = 0;

      for (; it != it_end; ++it) {
        const uword row = it.row();
        const uword col = it.col();

        if (row != col) {
          access::rw(tmp.values[count]) = (*it);
          access::rw(tmp.row_indices[count]) = row;
          access::rw(tmp.col_ptrs[col + 1])++;
          ++count;
        }
      }

      for (uword i = 0; i < tmp.n_cols; ++i) {
        access::rw(tmp.col_ptrs[i + 1]) += tmp.col_ptrs[i];
      }

      // quick resize without reallocating memory and copying data
      access::rw(tmp.n_nonzero) = count;
      access::rw(tmp.values[count]) = eT(0);
      access::rw(tmp.row_indices[count]) = uword(0);

      access::rw(m).steal_mem(tmp);
    } else  // val != eT(0)
    {
      SpMat<eT> tmp1;

      tmp1.eye(m.n_rows, m.n_cols);

      if (val != eT(1)) {
        tmp1 *= val;
      }

      SpMat<eT> tmp2;

      spglue_merge::diagview_merge(tmp2, m, tmp1);

      access::rw(m).steal_mem(tmp2);
    }
  } else {
    SpMat<eT>& x = const_cast<SpMat<eT>&>(m);

    const uword local_n_elem = n_elem;

    for (uword i = 0; i < local_n_elem; ++i) {
      x.at(i + row_offset, i + col_offset) = val;
    }
  }
}

template <typename eT>
inline void spdiagview<eT>::zeros() {
  arma_extra_debug_sigprint();

  (*this).fill(eT(0));
}

template <typename eT>
inline void spdiagview<eT>::ones() {
  arma_extra_debug_sigprint();

  (*this).fill(eT(1));
}

template <typename eT>
inline void spdiagview<eT>::randu() {
  arma_extra_debug_sigprint();

  SpMat<eT>& x = const_cast<SpMat<eT>&>(m);

  const uword local_n_elem = n_elem;

  for (uword i = 0; i < local_n_elem; ++i) {
    x.at(i + row_offset, i + col_offset) = eT(arma_rng::randu<eT>());
  }
}

template <typename eT>
inline void spdiagview<eT>::randn() {
  arma_extra_debug_sigprint();

  SpMat<eT>& x = const_cast<SpMat<eT>&>(m);

  const uword local_n_elem = n_elem;

  for (uword i = 0; i < local_n_elem; ++i) {
    x.at(i + row_offset, i + col_offset) = eT(arma_rng::randn<eT>());
  }
}

//! @}
