// 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_diagmat
//! @{

//! interpret a matrix or a vector as a diagonal matrix (ie. off-diagonal entries are
//! zero)
template <typename T1>
arma_warn_unused arma_inline
    typename enable_if2<is_arma_type<T1>::value, const Op<T1, op_diagmat> >::result
    diagmat(const T1& X) {
  arma_extra_debug_sigprint();

  return Op<T1, op_diagmat>(X);
}

//! create a matrix with the k-th diagonal set to the given vector
template <typename T1>
arma_warn_unused arma_inline
    typename enable_if2<is_arma_type<T1>::value, const Op<T1, op_diagmat2> >::result
    diagmat(const T1& X, const sword k) {
  arma_extra_debug_sigprint();

  const uword row_offset = (k < 0) ? uword(-k) : uword(0);
  const uword col_offset = (k > 0) ? uword(k) : uword(0);

  return Op<T1, op_diagmat2>(X, row_offset, col_offset);
}

template <typename T1>
arma_warn_unused inline const SpOp<T1, spop_diagmat> diagmat(
    const SpBase<typename T1::elem_type, T1>& X) {
  arma_extra_debug_sigprint();

  return SpOp<T1, spop_diagmat>(X.get_ref());
}

template <typename T1>
arma_warn_unused inline const SpOp<T1, spop_diagmat2> diagmat(
    const SpBase<typename T1::elem_type, T1>& X, const sword k) {
  arma_extra_debug_sigprint();

  const uword row_offset = (k < 0) ? uword(-k) : uword(0);
  const uword col_offset = (k > 0) ? uword(k) : uword(0);

  return SpOp<T1, spop_diagmat2>(X.get_ref(), row_offset, col_offset);
}

//! @}
