# include <stdio.h>
# include <stdlib.h>

# include "ppc_array.h"
# include "ppc_sparse_matrix.h"
# include "ppc_xmalloc.h"

/******************************************************************************/

void ccs_pack ( double **a, int m, int n, int *Ap, int *Ai, double *Ax )

/******************************************************************************/
/*
  Purpose:

    ccs_pack() packs an MxN sparse matrix to CCS format.

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    09 September 2023

  Author:

    John Burkardt

  Reference:

    Rouben Rostamian,
    Programming Projects in C 
    for Students of Engineering, Science, and Mathematics,
    SIAM, 2014,
    ISBN: 978-1-611973-49-5

  Input:

    double **a: the MxN matrix, which has already been allocated by the user.

    int m, n: the number of rows and columns of the matrix.

  Output:

    int *Ap[n+1]:

    int *Ai[nz]:

    double *Ax[nz]:
*/
{
  int i;
  int j;
  int nz;
/*
  Scan the MxN matrix.
*/
  nz = 0;
  Ap[nz] = 0;

  for ( j = 0; j < n; j++ )
  {
    for ( i = 0; i < m; i++ )
    {
      if ( a[i][j] != 0.0 )
      {
        Ap[j+1] = nz + 1;
        Ai[nz] = i;
        Ax[nz] = a[i][j];
        nz = nz + 1;
      }
    }
  }

  return;
}
/******************************************************************************/

void ccs_unpack ( double **a, int m, int n, int *Ap, int *Ai, double *Ax )

/******************************************************************************/
/*
  Purpose:

    ccs_unpack() unpacks a CCS sparse matrix to MxN format.

  Licensing:

    This code is distributed under the MIT license. 

  Modified:

    09 September 2023

  Author:

    John Burkardt

  Reference:

    Rouben Rostamian,
    Programming Projects in C 
    for Students of Engineering, Science, and Mathematics,
    SIAM, 2014,
    ISBN: 978-1-611973-49-5

  Input:

    int m, n: the number of rows and columns of the matrix.

    int *Ap:

    int *Ai:

    double *Ax:

  Output:

    double **a: the MxN matrix, which has already been allocated by the user.
*/
{
  int i;
  int j;
  int k;

  for ( i = 0; i < m; i++ )
  {
    for ( j = 0; j < n; j++ )
    {
      a[i][j] = 0.0;
    }
  }

  for ( j = 0; j < n; j++ )
  {
    for ( k = Ap[j]; k < Ap[j+1]; k++ )
    {
      i = Ai[k];
      a[i][j] = Ax[k];
    }
  }

  return;
}