// 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 op_cumsum
//! @{



template<typename eT>
inline
void
op_cumsum::apply_noalias(Mat<eT>& out, const Mat<eT>& X, const uword dim)
  {
  arma_extra_debug_sigprint();
  
  uword n_rows = X.n_rows;
  uword n_cols = X.n_cols;
  
  out.set_size(n_rows,n_cols);
  
  if(out.n_elem == 0)  { return; }
  
  if(dim == 0)
    {
    if(n_cols == 1)
      {
      const eT*   X_mem =   X.memptr();
            eT* out_mem = out.memptr();
      
      eT acc = eT(0);
      
      for(uword row=0; row < n_rows; ++row)
        {
        acc += X_mem[row];
        
        out_mem[row] = acc;
        }
      }
    else
      {
      for(uword col=0; col < n_cols; ++col)
        {
        const eT*   X_colmem =   X.colptr(col);
              eT* out_colmem = out.colptr(col);
        
        eT acc = eT(0);
        
        for(uword row=0; row < n_rows; ++row)
          {
          acc += X_colmem[row];
          
          out_colmem[row] = acc;
          }
        }
      }
    }
  else
  if(dim == 1)
    {
    if(n_rows == 1)
      {
      const eT*   X_mem =   X.memptr();
            eT* out_mem = out.memptr();
      
      eT acc = eT(0);
      
      for(uword col=0; col < n_cols; ++col)
        {
        acc += X_mem[col];
        
        out_mem[col] = acc;
        }
      }
    else
      {
      if(n_cols > 0)
        {
        arrayops::copy( out.colptr(0), X.colptr(0), n_rows );
        
        for(uword col=1; col < n_cols; ++col)
          {
          const eT* out_colmem_prev = out.colptr(col-1);
                eT* out_colmem      = out.colptr(col  );
          const eT*   X_colmem      =   X.colptr(col  );
          
          for(uword row=0; row < n_rows; ++row)
            {
            out_colmem[row] = out_colmem_prev[row] + X_colmem[row];
            }
          }
        }
      }
    }
  }



template<typename T1>
inline
void
op_cumsum::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_cumsum>& in)
  {
  arma_extra_debug_sigprint();
  
  typedef typename T1::elem_type eT;
  
  const uword dim = in.aux_uword_a;
  
  arma_debug_check( (dim > 1), "cumsum(): parameter 'dim' must be 0 or 1" );
  
  const quasi_unwrap<T1> U(in.m);
  
  if(U.is_alias(out))
    {
    Mat<eT> tmp;
    
    op_cumsum::apply_noalias(tmp, U.M, dim);
    
    out.steal_mem(tmp);
    }
  else
    {
    op_cumsum::apply_noalias(out, U.M, dim);
    }
  }



template<typename T1>
inline
void
op_cumsum_vec::apply(Mat<typename T1::elem_type>& out, const Op<T1,op_cumsum_vec>& in)
  {
  arma_extra_debug_sigprint();
  
  typedef typename T1::elem_type eT;
  
  const quasi_unwrap<T1> U(in.m);
  
  const uword dim = (T1::is_xvec) ? uword(U.M.is_rowvec() ? 1 : 0) : uword((T1::is_row) ? 1 : 0);
  
  if(U.is_alias(out))
    {
    Mat<eT> tmp;
    
    op_cumsum::apply_noalias(tmp, U.M, dim);
    
    out.steal_mem(tmp);
    }
  else
    {
    op_cumsum::apply_noalias(out, U.M, dim);
    }
  }



//! @}