// 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 fn_randn
//! @{

// scalars

arma_warn_unused inline double randn() {
  arma_debug_sigprint();

  return double(arma_rng::randn<double>());
}

template <typename eT>
arma_warn_unused inline typename arma_real_or_cx_only<eT>::result randn() {
  arma_debug_sigprint();

  return eT(arma_rng::randn<eT>());
}

arma_warn_unused inline double randn(const distr_param& param) {
  arma_debug_sigprint();

  if (param.state == 0) {
    return double(arma_rng::randn<double>());
  }

  double mu = double(0);
  double sd = double(1);

  param.get_double_vals(mu, sd);

  arma_conform_check(
      (sd <= double(0)),
      "randn(): incorrect distribution parameters; standard deviation must be > 0");

  const double val = double(arma_rng::randn<double>());

  return ((val * sd) + mu);
}

template <typename eT>
arma_warn_unused inline typename arma_real_or_cx_only<eT>::result randn(
    const distr_param& param) {
  arma_debug_sigprint();

  if (param.state == 0) {
    return eT(arma_rng::randn<eT>());
  }

  double mu = double(0);
  double sd = double(1);

  param.get_double_vals(mu, sd);

  arma_conform_check(
      (sd <= double(0)),
      "randn(): incorrect distribution parameters; standard deviation must be > 0");

  eT val = eT(0);

  arma_rng::randn<eT>::fill(&val, 1, mu, sd);  // using fill() as eT can be complex

  return val;
}

// vectors

arma_warn_unused inline vec randn(const uword n_elem,
                                  const distr_param& param = distr_param()) {
  arma_debug_sigprint();

  vec out(n_elem, arma_nozeros_indicator());

  if (param.state == 0) {
    arma_rng::randn<double>::fill(out.memptr(), n_elem);
  } else {
    double mu = double(0);
    double sd = double(1);

    param.get_double_vals(mu, sd);

    arma_conform_check(
        (sd <= double(0)),
        "randn(): incorrect distribution parameters; standard deviation must be > 0");

    arma_rng::randn<double>::fill(out.memptr(), n_elem, mu, sd);
  }

  return out;
}

template <typename obj_type>
arma_warn_unused inline obj_type randn(
    const uword n_elem, const distr_param& param = distr_param(),
    const typename arma_Mat_Col_Row_only<obj_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename obj_type::elem_type eT;

  const uword n_rows = (is_Row<obj_type>::value) ? uword(1) : n_elem;
  const uword n_cols = (is_Row<obj_type>::value) ? n_elem : uword(1);

  obj_type out(n_rows, n_cols, arma_nozeros_indicator());

  if (param.state == 0) {
    arma_rng::randn<eT>::fill(out.memptr(), out.n_elem);
  } else {
    double mu = double(0);
    double sd = double(1);

    param.get_double_vals(mu, sd);

    arma_conform_check(
        (sd <= double(0)),
        "randn(): incorrect distribution parameters; standard deviation must be > 0");

    arma_rng::randn<eT>::fill(out.memptr(), out.n_elem, mu, sd);
  }

  return out;
}

// matrices

arma_warn_unused inline mat randn(const uword n_rows, const uword n_cols,
                                  const distr_param& param = distr_param()) {
  arma_debug_sigprint();

  mat out(n_rows, n_cols, arma_nozeros_indicator());

  if (param.state == 0) {
    arma_rng::randn<double>::fill(out.memptr(), out.n_elem);
  } else {
    double mu = double(0);
    double sd = double(1);

    param.get_double_vals(mu, sd);

    arma_conform_check(
        (sd <= double(0)),
        "randn(): incorrect distribution parameters; standard deviation must be > 0");

    arma_rng::randn<double>::fill(out.memptr(), out.n_elem, mu, sd);
  }

  return out;
}

arma_warn_unused inline mat randn(const SizeMat& s,
                                  const distr_param& param = distr_param()) {
  arma_debug_sigprint();

  return randn(s.n_rows, s.n_cols, param);
}

template <typename obj_type>
arma_warn_unused inline obj_type randn(
    const uword n_rows, const uword n_cols, const distr_param& param = distr_param(),
    const typename arma_Mat_Col_Row_only<obj_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename obj_type::elem_type eT;

  if (is_Col<obj_type>::value) {
    arma_conform_check((n_cols != 1), "randn(): incompatible size");
  }
  if (is_Row<obj_type>::value) {
    arma_conform_check((n_rows != 1), "randn(): incompatible size");
  }

  obj_type out(n_rows, n_cols, arma_nozeros_indicator());

  if (param.state == 0) {
    arma_rng::randn<eT>::fill(out.memptr(), out.n_elem);
  } else {
    double mu = double(0);
    double sd = double(1);

    param.get_double_vals(mu, sd);

    arma_conform_check(
        (sd <= double(0)),
        "randn(): incorrect distribution parameters; standard deviation must be > 0");

    arma_rng::randn<eT>::fill(out.memptr(), out.n_elem, mu, sd);
  }

  return out;
}

template <typename obj_type>
arma_warn_unused inline obj_type randn(
    const SizeMat& s, const distr_param& param = distr_param(),
    const typename arma_Mat_Col_Row_only<obj_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  return randn<obj_type>(s.n_rows, s.n_cols, param);
}

// cubes

arma_warn_unused inline cube randn(const uword n_rows, const uword n_cols,
                                   const uword n_slices,
                                   const distr_param& param = distr_param()) {
  arma_debug_sigprint();

  cube out(n_rows, n_cols, n_slices, arma_nozeros_indicator());

  if (param.state == 0) {
    arma_rng::randn<double>::fill(out.memptr(), out.n_elem);
  } else {
    double mu = double(0);
    double sd = double(1);

    param.get_double_vals(mu, sd);

    arma_conform_check(
        (sd <= double(0)),
        "randn(): incorrect distribution parameters; standard deviation must be > 0");

    arma_rng::randn<double>::fill(out.memptr(), out.n_elem, mu, sd);
  }

  return out;
}

arma_warn_unused inline cube randn(const SizeCube& s,
                                   const distr_param& param = distr_param()) {
  arma_debug_sigprint();

  return randn(s.n_rows, s.n_cols, s.n_slices, param);
}

template <typename cube_type>
arma_warn_unused inline cube_type randn(
    const uword n_rows, const uword n_cols, const uword n_slices,
    const distr_param& param = distr_param(),
    const typename arma_Cube_only<cube_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  typedef typename cube_type::elem_type eT;

  cube_type out(n_rows, n_cols, n_slices, arma_nozeros_indicator());

  if (param.state == 0) {
    arma_rng::randn<eT>::fill(out.memptr(), out.n_elem);
  } else {
    double mu = double(0);
    double sd = double(1);

    param.get_double_vals(mu, sd);

    arma_conform_check(
        (sd <= double(0)),
        "randn(): incorrect distribution parameters; standard deviation must be > 0");

    arma_rng::randn<eT>::fill(out.memptr(), out.n_elem, mu, sd);
  }

  return out;
}

template <typename cube_type>
arma_warn_unused inline cube_type randn(
    const SizeCube& s, const distr_param& param = distr_param(),
    const typename arma_Cube_only<cube_type>::result* junk = nullptr) {
  arma_debug_sigprint();
  arma_ignore(junk);

  return randn<cube_type>(s.n_rows, s.n_cols, s.n_slices, param);
}

//! @}
