// 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 Gen
//! @{

template <typename T1, typename gen_type>
arma_inline Gen<T1, gen_type>::Gen(const uword in_n_rows, const uword in_n_cols)
    : n_rows(in_n_rows), n_cols(in_n_cols) {
  arma_debug_sigprint();
}

template <typename T1, typename gen_type>
arma_inline Gen<T1, gen_type>::~Gen() {
  arma_debug_sigprint();
}

template <typename T1, typename gen_type>
arma_inline typename T1::elem_type Gen<T1, gen_type>::operator[](const uword ii) const {
  typedef typename T1::elem_type eT;

  if (is_same_type<gen_type, gen_zeros>::yes) {
    return eT(0);
  } else if (is_same_type<gen_type, gen_ones>::yes) {
    return eT(1);
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    return ((ii % n_rows) == (ii / n_rows)) ? eT(1) : eT(0);
  }

  return eT(0);  // prevent pedantic compiler warnings
}

template <typename T1, typename gen_type>
arma_inline typename T1::elem_type Gen<T1, gen_type>::at(const uword r,
                                                         const uword c) const {
  typedef typename T1::elem_type eT;

  if (is_same_type<gen_type, gen_zeros>::yes) {
    return eT(0);
  } else if (is_same_type<gen_type, gen_ones>::yes) {
    return eT(1);
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    return (r == c) ? eT(1) : eT(0);
  }

  return eT(0);  // prevent pedantic compiler warnings
}

template <typename T1, typename gen_type>
arma_inline typename T1::elem_type Gen<T1, gen_type>::at_alt(const uword ii) const {
  return operator[](ii);
}

template <typename T1, typename gen_type>
inline void Gen<T1, gen_type>::apply(Mat<typename T1::elem_type>& out) const {
  arma_debug_sigprint();

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

  if (is_same_type<gen_type, gen_zeros>::yes) {
    out.zeros();
  } else if (is_same_type<gen_type, gen_ones>::yes) {
    out.ones();
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    out.eye();
  }
}

template <typename T1, typename gen_type>
inline void Gen<T1, gen_type>::apply_inplace_plus(
    Mat<typename T1::elem_type>& out) const {
  arma_debug_sigprint();

  arma_conform_assert_same_size(out.n_rows, out.n_cols, n_rows, n_cols, "addition");

  typedef typename T1::elem_type eT;

  if (is_same_type<gen_type, gen_ones>::yes) {
    arrayops::inplace_plus(out.memptr(), eT(1), out.n_elem);
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    const uword N = (std::min)(n_rows, n_cols);

    for (uword ii = 0; ii < N; ++ii) {
      out.at(ii, ii) += eT(1);
    }
  }
}

template <typename T1, typename gen_type>
inline void Gen<T1, gen_type>::apply_inplace_minus(
    Mat<typename T1::elem_type>& out) const {
  arma_debug_sigprint();

  arma_conform_assert_same_size(out.n_rows, out.n_cols, n_rows, n_cols, "subtraction");

  typedef typename T1::elem_type eT;

  if (is_same_type<gen_type, gen_ones>::yes) {
    arrayops::inplace_minus(out.memptr(), eT(1), out.n_elem);
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    const uword N = (std::min)(n_rows, n_cols);

    for (uword ii = 0; ii < N; ++ii) {
      out.at(ii, ii) -= eT(1);
    }
  }
}

template <typename T1, typename gen_type>
inline void Gen<T1, gen_type>::apply_inplace_schur(
    Mat<typename T1::elem_type>& out) const {
  arma_debug_sigprint();

  arma_conform_assert_same_size(out.n_rows, out.n_cols, n_rows, n_cols,
                                "element-wise multiplication");

  typedef typename T1::elem_type eT;

  if (is_same_type<gen_type, gen_zeros>::yes) {
    arrayops::inplace_mul(out.memptr(), eT(0), out.n_elem);
    // NOTE: not using arrayops::fill_zeros(), as 'out' may have NaN elements
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    for (uword c = 0; c < n_cols; ++c)
      for (uword r = 0; r < n_rows; ++r) {
        if (r != c) {
          out.at(r, c) *= eT(0);
        }
      }
  }
}

template <typename T1, typename gen_type>
inline void Gen<T1, gen_type>::apply_inplace_div(Mat<typename T1::elem_type>& out) const {
  arma_debug_sigprint();

  arma_conform_assert_same_size(out.n_rows, out.n_cols, n_rows, n_cols,
                                "element-wise division");

  typedef typename T1::elem_type eT;

  if (is_same_type<gen_type, gen_zeros>::yes) {
    arrayops::inplace_div(out.memptr(), eT(0), out.n_elem);
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    for (uword c = 0; c < n_cols; ++c)
      for (uword r = 0; r < n_rows; ++r) {
        if (r != c) {
          out.at(r, c) /= eT(0);
        }
      }
  }
}

template <typename T1, typename gen_type>
inline void Gen<T1, gen_type>::apply(subview<typename T1::elem_type>& out) const {
  arma_debug_sigprint();

  // NOTE: we're assuming that the submatrix has the same dimensions as the Gen object
  // this is checked by subview::operator=()

  if (is_same_type<gen_type, gen_zeros>::yes) {
    out.zeros();
  } else if (is_same_type<gen_type, gen_ones>::yes) {
    out.ones();
  } else if (is_same_type<gen_type, gen_eye>::yes) {
    out.eye();
  }
}

//! @}
