/*
*
* Template Numerical Toolkit (TNT)
*
* Mathematical and Computational Sciences Division
* National Institute of Technology,
* Gaithersburg, MD USA
*
*
* This software was developed at the National Institute of Standards and
* Technology (NIST) by employees of the Federal Government in the course
* of their official duties. Pursuant to title 17 Section 105 of the
* United States Code, this software is not subject to copyright protection
* and is in the public domain. NIST assumes no responsibility whatsoever for
* its use by other parties, and makes no guarantees, expressed or implied,
* about its quality, reliability, or any other characteristic.
*
*/

#ifndef IMPALGEBRA_TNT_SPARSE_MATRIX_CSR_H
#define IMPALGEBRA_TNT_SPARSE_MATRIX_CSR_H

#include <IMP/algebra/algebra_config.h>
#include "tnt_array1d.h"

IMPALGEBRA_BEGIN_INTERNAL_NAMESPACE
namespace TNT
{
using namespace std;


/**
  Read-only view of a sparse matrix in compressed-row storage
  format.  Neither array elements (nonzeros) nor sparsity
  structure can be modified.  If modifications are required,
  create a new view.

  <p>
  Index values begin at 0.

  <p>
  <b>Storage requirements:</b> An (m x n) matrix with
  nz nonzeros requires no more than  ((T+I)*nz + M*I)
  bytes, where T is the size of data elements and
  I is the size of integers.


*/
template <class T>
class Sparse_Matrix_CompRow {

private:
  Array1D<T>    val_;       // data values (nz_ elements)
    Array1D<int>  rowptr_;    // row_ptr (dim_[0]+1 elements)
    Array1D<int>  colind_;    // col_ind  (nz_ elements)

    int dim1_;        // number of rows
    int dim2_;        // number of cols

public:

  Sparse_Matrix_CompRow(const Sparse_Matrix_CompRow &S);
  Sparse_Matrix_CompRow(int M, int N, int nz, const T *val,
            const int *r, const int *c);



    inline   const T&      val(int i) const { return val_[i]; }
    inline   const int&         row_ptr(int i) const { return rowptr_[i]; }
    inline   const int&         col_ind(int i) const { return colind_[i];}

    inline   int    dim1() const {return dim1_;}
    inline   int    dim2() const {return dim2_;}
       int          NumNonzeros() const {return val_.dim1();}


    Sparse_Matrix_CompRow& operator=(
          const Sparse_Matrix_CompRow &R);



};

/**
  Construct a read-only view of existing sparse matrix in
  compressed-row storage format.

  @param M the number of rows of sparse matrix
  @param N the  number of columns of sparse matrix
  @param nz the number of nonzeros
  @param val a contiguous list of nonzero values
  @param r row-pointers: r[i] denotes the begining position of row i
    (i.e. the ith row begins at val[row[i]]).
  @param c column-indices: c[i] denotes the column location of val[i]
*/
template <class T>
Sparse_Matrix_CompRow<T>::Sparse_Matrix_CompRow(int M, int N, int nz,
  const T *val, const int *r, const int *c) : val_(nz,val),
    rowptr_(M, r), colind_(nz, c), dim1_(M), dim2_(N) {}


}
// namespace TNT

IMPALGEBRA_END_INTERNAL_NAMESPACE

#endif /* IMPALGEBRA_TNT_SPARSE_MATRIX_CSR_H */