smat.h

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#ifndef SMAT_H
#define SMAT_H

#include <itpp/base/svec.h>
#include <itpp/itexports.h>

namespace itpp
{

// Declaration of class Vec
template <class T> class Vec;
// Declaration of class Mat
template <class T> class Mat;
// Declaration of class Sparse_Vec
template <class T> class Sparse_Vec;
// Declaration of class Sparse_Mat
template <class T> class Sparse_Mat;

// ------------------------ Sparse_Mat Friends -------------------------------------

template <class T>
Sparse_Mat<T> operator+(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

template <class T>
Sparse_Mat<T> operator*(const T &c, const Sparse_Mat<T> &m);

template <class T>
Sparse_Mat<T> operator*(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

template <class T>
Sparse_Vec<T> operator*(const Sparse_Mat<T> &m, const Sparse_Vec<T> &v);

template <class T>
Vec<T> operator*(const Sparse_Mat<T> &m, const Vec<T> &v);

template <class T>
Vec<T> operator*(const Vec<T> &v, const Sparse_Mat<T> &m);

template <class T>
Mat<T> trans_mult(const Sparse_Mat<T> &m);

template <class T>
Sparse_Mat<T> trans_mult_s(const Sparse_Mat<T> &m);

template <class T>
Sparse_Mat<T> trans_mult(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

template <class T>
Vec<T> trans_mult(const Sparse_Mat<T> &m, const Vec<T> &v);

template <class T>
Sparse_Mat<T> mult_trans(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

template <class T>
class Sparse_Mat
{
public:

  Sparse_Mat();

  Sparse_Mat(int rows, int cols, int row_data_init = 200);

  Sparse_Mat(const Sparse_Mat<T> &m);

  Sparse_Mat(const Mat<T> &m);

  Sparse_Mat(const Mat<T> &m, T epsilon);

  ~Sparse_Mat();

  void set_size(int rows, int cols, int row_data_init = -1);

  int rows() const { return n_rows; }

  int cols() const { return n_cols; }

  int nnz();

  double density();

  void compact();

  void full(Mat<T> &m) const;

  Mat<T> full() const;

  T operator()(int r, int c) const;

  void set(int r, int c, T v);

  void set_new(int r, int c, T v);

  void add_elem(const int r, const int c, const T v);

  void zeros();

  void zero_elem(const int r, const int c);

  void clear();

  void clear_elem(const int r, const int c);

  void set_submatrix(int r1, int r2, int c1, int c2, const Mat<T> &m);

  void set_submatrix(int r, int c, const Mat<T>& m);

  Sparse_Mat<T> get_submatrix(int r1, int r2, int c1, int c2) const;

  Sparse_Mat<T> get_submatrix_cols(int c1, int c2) const;

  void get_col(int c, Sparse_Vec<T> &v) const;

  Sparse_Vec<T> get_col(int c) const;

  void set_col(int c, const Sparse_Vec<T> &v);

  void transpose(Sparse_Mat<T> &m) const;

  Sparse_Mat<T> transpose() const;

  // Sparse_Mat<T> T() const { return this->transpose(); };

  void operator=(const Sparse_Mat<T> &m);

  void operator=(const Mat<T> &m);

  Sparse_Mat<T> operator-() const;

  bool operator==(const Sparse_Mat<T> &m) const;

  void operator+=(const Sparse_Mat<T> &v);

  void operator+=(const Mat<T> &v);

  void operator-=(const Sparse_Mat<T> &v);

  void operator-=(const Mat<T> &v);

  void operator*=(const T &v);

  void operator/=(const T &v);

  friend Sparse_Mat<T> operator+<>(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

  friend Sparse_Mat<T> operator*<>(const T &c, const Sparse_Mat<T> &m);

  friend Sparse_Mat<T> operator*<>(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

  friend Sparse_Vec<T> operator*<>(const Sparse_Mat<T> &m, const Sparse_Vec<T> &v);

  friend Vec<T> operator*<>(const Sparse_Mat<T> &m, const Vec<T> &v);

  friend Vec<T> operator*<>(const Vec<T> &v, const Sparse_Mat<T> &m);

  friend Mat<T> trans_mult <>(const Sparse_Mat<T> &m);

  friend Sparse_Mat<T> trans_mult_s <>(const Sparse_Mat<T> &m);

  friend Sparse_Mat<T> trans_mult <>(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

  friend Vec<T> trans_mult <>(const Sparse_Mat<T> &m, const Vec<T> &v);

  friend Sparse_Mat<T> mult_trans <>(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2);

private:
  void init();
  void alloc_empty();
  void alloc(int row_data_size = 200);
  void free();

  int n_rows, n_cols;
  Sparse_Vec<T> *col;
};

typedef Sparse_Mat<int> sparse_imat;

typedef Sparse_Mat<double> sparse_mat;

typedef Sparse_Mat<std::complex<double> > sparse_cmat;

//---------------------- Implementation starts here --------------------------------

template <class T>
void Sparse_Mat<T>::init()
{
  n_rows = 0;
  n_cols = 0;
  col = 0;
}

template <class T>
void Sparse_Mat<T>::alloc_empty()
{
  if (n_cols == 0)
    col = 0;
  else
    col = new Sparse_Vec<T>[n_cols];
}

template <class T>
void Sparse_Mat<T>::alloc(int row_data_init)
{
  if (n_cols == 0)
    col = 0;
  else
    col = new Sparse_Vec<T>[n_cols];
  for (int c = 0; c < n_cols; c++)
    col[c].set_size(n_rows, row_data_init);
}

template <class T>
void Sparse_Mat<T>::free()
{
  delete [] col;
  col = 0;
}

template <class T>
Sparse_Mat<T>::Sparse_Mat()
{
  init();
}

template <class T>
Sparse_Mat<T>::Sparse_Mat(int rows, int cols, int row_data_init)
{
  init();
  n_rows = rows;
  n_cols = cols;
  alloc(row_data_init);
}

template <class T>
Sparse_Mat<T>::Sparse_Mat(const Sparse_Mat<T> &m)
{
  init();
  n_rows = m.n_rows;
  n_cols = m.n_cols;
  alloc_empty();

  for (int c = 0; c < n_cols; c++)
    col[c] = m.col[c];
}

template <class T>
Sparse_Mat<T>::Sparse_Mat(const Mat<T> &m)
{
  init();
  n_rows = m.rows();
  n_cols = m.cols();
  alloc();

  for (int c = 0; c < n_cols; c++) {
    for (int r = 0; r < n_rows; r++) {
      //if (abs(m(r,c)) != T(0))
      if (m(r, c) != T(0))
        col[c].set_new(r, m(r, c));
    }
    col[c].compact();
  }
}

template <class T>
Sparse_Mat<T>::Sparse_Mat(const Mat<T> &m, T epsilon)
{
  init();
  n_rows = m.rows();
  n_cols = m.cols();
  alloc();

  for (int c = 0; c < n_cols; c++) {
    for (int r = 0; r < n_rows; r++) {
      if (std::abs(m(r, c)) > std::abs(epsilon))
        col[c].set_new(r, m(r, c));
    }
    col[c].compact();
  }
}

template <class T>
Sparse_Mat<T>::~Sparse_Mat()
{
  free();
}

template <class T>
void Sparse_Mat<T>::set_size(int rows, int cols, int row_data_init)
{
  n_rows = rows;

  //Allocate new memory for data if the number of columns has changed or if row_data_init != -1
  if (cols != n_cols || row_data_init != -1) {
    n_cols = cols;
    free();
    alloc(row_data_init);
  }
}

template <class T>
int Sparse_Mat<T>::nnz()
{
  int n = 0;
  for (int c = 0; c < n_cols; c++)
    n += col[c].nnz();

  return n;
}

template <class T>
double Sparse_Mat<T>::density()
{
  //return static_cast<double>(nnz())/(n_rows*n_cols);
  return double(nnz()) / (n_rows*n_cols);
}

template <class T>
void Sparse_Mat<T>::compact()
{
  for (int c = 0; c < n_cols; c++)
    col[c].compact();
}

template <class T>
void Sparse_Mat<T>::full(Mat<T> &m) const
{
  m.set_size(n_rows, n_cols);
  m = T(0);
  for (int c = 0; c < n_cols; c++) {
    for (int p = 0; p < col[c].nnz(); p++)
      m(col[c].get_nz_index(p), c) = col[c].get_nz_data(p);
  }
}

template <class T>
Mat<T> Sparse_Mat<T>::full() const
{
  Mat<T> r(n_rows, n_cols);
  full(r);
  return r;
}

template <class T>
T Sparse_Mat<T>::operator()(int r, int c) const
{
  it_assert_debug(r >= 0 && r<n_rows && c >= 0 && c < n_cols, "Incorrect input indexes given");
  return col[c](r);
}

template <class T>
void Sparse_Mat<T>::set(int r, int c, T v)
{
  it_assert_debug(r >= 0 && r<n_rows && c >= 0 && c < n_cols, "Incorrect input indexes given");
  col[c].set(r, v);
}

template <class T>
void Sparse_Mat<T>::set_new(int r, int c, T v)
{
  it_assert_debug(r >= 0 && r<n_rows && c >= 0 && c < n_cols, "Incorrect input indexes given");
  col[c].set_new(r, v);
}

template <class T>
void Sparse_Mat<T>::add_elem(int r, int c, T v)
{
  it_assert_debug(r >= 0 && r<n_rows && c >= 0 && c < n_cols, "Incorrect input indexes given");
  col[c].add_elem(r, v);
}

template <class T>
void Sparse_Mat<T>::zeros()
{
  for (int c = 0; c < n_cols; c++)
    col[c].zeros();
}

template <class T>
void Sparse_Mat<T>::zero_elem(const int r, const int c)
{
  it_assert_debug(r >= 0 && r<n_rows && c >= 0 && c < n_cols, "Incorrect input indexes given");
  col[c].zero_elem(r);
}

template <class T>
void Sparse_Mat<T>::clear()
{
  for (int c = 0; c < n_cols; c++)
    col[c].clear();
}

template <class T>
void Sparse_Mat<T>::clear_elem(const int r, const int c)
{
  it_assert_debug(r >= 0 && r<n_rows && c >= 0 && c < n_cols, "Incorrect input indexes given");
  col[c].clear_elem(r);
}

template <class T>
void Sparse_Mat<T>::set_submatrix(int r1, int r2, int c1, int c2, const Mat<T>& m)
{
  if (r1 == -1) r1 = n_rows - 1;
  if (r2 == -1) r2 = n_rows - 1;
  if (c1 == -1) c1 = n_cols - 1;
  if (c2 == -1) c2 = n_cols - 1;

  it_assert_debug(r1 >= 0 && r2 >= 0 && r1 < n_rows && r2 < n_rows &&
                  c1 >= 0 && c2 >= 0 && c1 < n_cols && c2 < n_cols, "Sparse_Mat<Num_T>::set_submatrix(): index out of range");

  it_assert_debug(r2 >= r1 && c2 >= c1, "Sparse_Mat<Num_T>::set_submatrix: r2<r1 or c2<c1");
  it_assert_debug(m.rows() == r2 - r1 + 1 && m.cols() == c2 - c1 + 1, "Mat<Num_T>::set_submatrix(): sizes don't match");

  for (int i = 0 ; i < m.rows() ; i++) {
    for (int j = 0 ; j < m.cols() ; j++) {
      set(r1 + i, c1 + j, m(i, j));
    }
  }
}

template <class T>
void Sparse_Mat<T>::set_submatrix(int r, int c, const Mat<T>& m)
{
  it_assert_debug(r >= 0 && r + m.rows() <= n_rows &&
                  c >= 0 && c + m.cols() <= n_cols, "Sparse_Mat<Num_T>::set_submatrix(): index out of range");

  for (int i = 0 ; i < m.rows() ; i++) {
    for (int j = 0 ; j < m.cols() ; j++) {
      set(r + i, c + j, m(i, j));
    }
  }
}

template <class T>
Sparse_Mat<T> Sparse_Mat<T>::get_submatrix(int r1, int r2, int c1, int c2) const
{
  it_assert_debug(r1 <= r2 && r1 >= 0 && r1 < n_rows && c1 <= c2 && c1 >= 0 && c1 < n_cols,
                  "Sparse_Mat<T>::get_submatrix(): illegal input variables");

  Sparse_Mat<T> r(r2 - r1 + 1, c2 - c1 + 1);

  for (int c = c1; c <= c2; c++)
    r.col[c-c1] = col[c].get_subvector(r1, r2);
  r.compact();

  return r;
}

template <class T>
Sparse_Mat<T> Sparse_Mat<T>::get_submatrix_cols(int c1, int c2) const
{
  it_assert_debug(c1 <= c2 && c1 >= 0 && c1 < n_cols, "Sparse_Mat<T>::get_submatrix_cols()");
  Sparse_Mat<T> r(n_rows, c2 - c1 + 1, 0);

  for (int c = c1; c <= c2; c++)
    r.col[c-c1] = col[c];
  r.compact();

  return r;
}

template <class T>
void Sparse_Mat<T>::get_col(int c, Sparse_Vec<T> &v) const
{
  it_assert(c >= 0 && c < n_cols, "Sparse_Mat<T>::get_col()");
  v = col[c];
}

template <class T>
Sparse_Vec<T> Sparse_Mat<T>::get_col(int c) const
{
  it_assert(c >= 0 && c < n_cols, "Sparse_Mat<T>::get_col()");
  return col[c];
}

template <class T>
void Sparse_Mat<T>::set_col(int c, const Sparse_Vec<T> &v)
{
  it_assert(c >= 0 && c < n_cols, "Sparse_Mat<T>::set_col()");
  col[c] = v;
}

template <class T>
void Sparse_Mat<T>::transpose(Sparse_Mat<T> &m) const
{
  m.set_size(n_cols, n_rows);
  for (int c = 0; c < n_cols; c++) {
    for (int p = 0; p < col[c].nnz(); p++)
      m.col[col[c].get_nz_index(p)].set_new(c, col[c].get_nz_data(p));
  }
}

template <class T>
Sparse_Mat<T> Sparse_Mat<T>::transpose() const
{
  Sparse_Mat<T> m;
  transpose(m);
  return m;
}

template <class T>
void Sparse_Mat<T>::operator=(const Sparse_Mat<T> &m)
{
  free();
  n_rows = m.n_rows;
  n_cols = m.n_cols;
  alloc_empty();

  for (int c = 0; c < n_cols; c++)
    col[c] = m.col[c];
}

template <class T>
void Sparse_Mat<T>::operator=(const Mat<T> &m)
{
  free();
  n_rows = m.rows();
  n_cols = m.cols();
  alloc();

  for (int c = 0; c < n_cols; c++) {
    for (int r = 0; r < n_rows; r++) {
      if (m(r, c) != T(0))
        col[c].set_new(r, m(r, c));
    }
    col[c].compact();
  }
}

template <class T>
Sparse_Mat<T> Sparse_Mat<T>::operator-() const
{
  Sparse_Mat r(n_rows, n_cols, 0);

  for (int c = 0; c < n_cols; c++) {
    r.col[c].resize_data(col[c].nnz());
    for (int p = 0; p < col[c].nnz(); p++)
      r.col[c].set_new(col[c].get_nz_index(p), -col[c].get_nz_data(p));
  }

  return r;
}

template <class T>
bool Sparse_Mat<T>::operator==(const Sparse_Mat<T> &m) const
{
  if (n_rows != m.n_rows || n_cols != m.n_cols)
    return false;
  for (int c = 0; c < n_cols; c++) {
    if (!(col[c] == m.col[c]))
      return false;
  }
  // If they passed all tests, they must be equal
  return true;
}

template <class T>
void Sparse_Mat<T>::operator+=(const Sparse_Mat<T> &m)
{
  it_assert_debug(m.rows() == n_rows && m.cols() == n_cols, "Addition of unequal sized matrices is not allowed");

  Sparse_Vec<T> v;
  for (int c = 0; c < n_cols; c++) {
    m.get_col(c, v);
    col[c] += v;
  }
}

template <class T>
void Sparse_Mat<T>::operator+=(const Mat<T> &m)
{
  it_assert_debug(m.rows() == n_rows && m.cols() == n_cols, "Addition of unequal sized matrices is not allowed");

  for (int c = 0; c < n_cols; c++)
    col[c] += (m.get_col(c));
}

template <class T>
void Sparse_Mat<T>::operator-=(const Sparse_Mat<T> &m)
{
  it_assert_debug(m.rows() == n_rows && m.cols() == n_cols, "Subtraction of unequal sized matrices is not allowed");

  Sparse_Vec<T> v;
  for (int c = 0; c < n_cols; c++) {
    m.get_col(c, v);
    col[c] -= v;
  }
}

template <class T>
void Sparse_Mat<T>::operator-=(const Mat<T> &m)
{
  it_assert_debug(m.rows() == n_rows && m.cols() == n_cols, "Subtraction of unequal sized matrices is not allowed");

  for (int c = 0; c < n_cols; c++)
    col[c] -= (m.get_col(c));
}

template <class T>
void Sparse_Mat<T>::operator*=(const T &m)
{
  for (int c = 0; c < n_cols; c++)
    col[c] *= m;
}

template <class T>
void Sparse_Mat<T>::operator/=(const T &m)
{
  for (int c = 0; c < n_cols; c++)
    col[c] /= m;
}

template <class T>
Sparse_Mat<T> operator+(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2)
{
  it_assert_debug(m1.n_cols == m2.n_cols && m1.n_rows == m2.n_rows , "Sparse_Mat<T> + Sparse_Mat<T>");

  Sparse_Mat<T> m(m1.n_rows, m1.n_cols, 0);

  for (int c = 0; c < m.n_cols; c++)
    m.col[c] = m1.col[c] + m2.col[c];

  return m;
}

// This function added by EGL, May'05
template <class T>
Sparse_Mat<T> operator*(const T &c, const Sparse_Mat<T> &m)
{
  int i, j;
  Sparse_Mat<T> ret(m.n_rows, m.n_cols);
  for (j = 0; j < m.n_cols; j++) {
    for (i = 0; i < m.col[j].nnz(); i++) {
      T x = c * m.col[j].get_nz_data(i);
      int k = m.col[j].get_nz_index(i);
      ret.set_new(k, j, x);
    }
  }
  return ret;
}

template <class T>
Sparse_Mat<T> operator*(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2)
{
  it_assert_debug(m1.n_cols == m2.n_rows, "Sparse_Mat<T> * Sparse_Mat<T>");

  Sparse_Mat<T> ret(m1.n_rows, m2.n_cols);

  for (int c = 0; c < m2.n_cols; c++) {
    Sparse_Vec<T> &m2colc = m2.col[c];
    for (int p2 = 0; p2 < m2colc.nnz(); p2++) {
      Sparse_Vec<T> &mcol = m1.col[m2colc.get_nz_index(p2)];
      T x = m2colc.get_nz_data(p2);
      for (int p1 = 0; p1 < mcol.nnz(); p1++) {
        int r = mcol.get_nz_index(p1);
        T inc = mcol.get_nz_data(p1) * x;
        ret.col[c].add_elem(r, inc);
      }
    }
  }
  // old code
  /*       for (int c=0; c<m2.n_cols; c++) { */
  /*  for (int p2=0; p2<m2.col[c].nnz(); p2++) { */
  /*    Sparse_Vec<T> &mcol = m1.col[m2.col[c].get_nz_index(p2)]; */
  /*    for (int p1=0; p1<mcol.nnz(); p1++) { */
  /*      int r = mcol.get_nz_index(p1); */
  /*      T inc = mcol.get_nz_data(p1) * m2.col[c].get_nz_data(p2); */
  /*      ret.col[c].add_elem(r,inc); */
  /*    } */
  /*  } */
  /*       } */
  ret.compact();
  return ret;
}


// This is apparently buggy.
/*   template <class T> */
/*     Sparse_Mat<T> operator*(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2) */
/*     { */
/*       it_assert_debug(m1.n_cols == m2.n_rows, "Sparse_Mat<T> * Sparse_Mat<T>"); */

/*       Sparse_Mat<T> ret(m1.n_rows, m2.n_cols); */
/*       ivec occupied_by(ret.n_rows), pos(ret.n_rows); */
/*       for (int rp=0; rp<m1.n_rows; rp++) */
/*  occupied_by[rp] = -1; */
/*       for (int c=0; c<ret.n_cols; c++) { */
/*  Sparse_Vec<T> &m2col = m2.col[c]; */
/*  for (int p2=0; p2<m2col.nnz(); p2++) { */
/*    Sparse_Vec<T> &m1col = m1.col[m2col.get_nz_index(p2)]; */
/*    for (int p1=0; p1<m1col.nnz(); p1++) { */
/*      int r = m1col.get_nz_index(p1); */
/*      T inc = m1col.get_nz_data(p1) * m2col.get_nz_data(p2); */
/*      if (occupied_by[r] == c) { */
/*        int index=ret.col[c].get_nz_index(pos[r]); */
/*        ret.col[c].add_elem(index,inc); */
/*      } */
/*      else { */
/*        occupied_by[r] = c; */
/*        pos[r] = ret.col[c].nnz(); */
/*        ret.col[c].set_new(r, inc); */
/*      } */
/*    } */
/*  } */
/*       } */
/*       ret.compact(); */

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


// This function added by EGL, May'05
template <class T>
Sparse_Vec<T> operator*(const Sparse_Mat<T> &m, const Sparse_Vec<T> &v)
{
  it_assert_debug(m.n_cols == v.size(), "Sparse_Mat<T> * Sparse_Vec<T>");

  Sparse_Vec<T> ret(m.n_rows);

  /* The two lines below added because the input parameter "v" is
  declared const, but the some functions (e.g., nnz()) change
  the vector... Is there a better workaround? */
  Sparse_Vec<T> vv = v;

  for (int p2 = 0; p2 < vv.nnz(); p2++) {
    Sparse_Vec<T> &mcol = m.col[vv.get_nz_index(p2)];
    T x = vv.get_nz_data(p2);
    for (int p1 = 0; p1 < mcol.nnz(); p1++) {
      int r = mcol.get_nz_index(p1);
      T inc = mcol.get_nz_data(p1) * x;
      ret.add_elem(r, inc);
    }
  }
  ret.compact();
  return ret;
}


template <class T>
Vec<T> operator*(const Sparse_Mat<T> &m, const Vec<T> &v)
{
  it_assert_debug(m.n_cols == v.size(), "Sparse_Mat<T> * Vec<T>");

  Vec<T> r(m.n_rows);
  r.clear();

  for (int c = 0; c < m.n_cols; c++) {
    for (int p = 0; p < m.col[c].nnz(); p++)
      r(m.col[c].get_nz_index(p)) += m.col[c].get_nz_data(p) * v(c);
  }

  return r;
}

template <class T>
Vec<T> operator*(const Vec<T> &v, const Sparse_Mat<T> &m)
{
  it_assert_debug(v.size() == m.n_rows, "Vec<T> * Sparse_Mat<T>");

  Vec<T> r(m.n_cols);
  r.clear();

  for (int c = 0; c < m.n_cols; c++)
    r[c] = v * m.col[c];

  return r;
}

template <class T>
Mat<T> trans_mult(const Sparse_Mat<T> &m)
{
  Mat<T> ret(m.n_cols, m.n_cols);
  Vec<T> col;
  for (int c = 0; c < ret.cols(); c++) {
    m.col[c].full(col);
    for (int r = 0; r < c; r++) {
      T tmp = m.col[r] * col;
      ret(r, c) = tmp;
      ret(c, r) = tmp;
    }
    ret(c, c) = m.col[c].sqr();
  }

  return ret;
}

template <class T>
Sparse_Mat<T> trans_mult_s(const Sparse_Mat<T> &m)
{
  Sparse_Mat<T> ret(m.n_cols, m.n_cols);
  Vec<T> col;
  T tmp;
  for (int c = 0; c < ret.n_cols; c++) {
    m.col[c].full(col);
    for (int r = 0; r < c; r++) {
      tmp = m.col[r] * col;
      if (tmp != T(0)) {
        ret.col[c].set_new(r, tmp);
        ret.col[r].set_new(c, tmp);
      }
    }
    tmp = m.col[c].sqr();
    if (tmp != T(0))
      ret.col[c].set_new(c, tmp);
  }

  return ret;
}

template <class T>
Sparse_Mat<T> trans_mult(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2)
{
  it_assert_debug(m1.n_rows == m2.n_rows, "trans_mult()");

  Sparse_Mat<T> ret(m1.n_cols, m2.n_cols);
  Vec<T> col;
  for (int c = 0; c < ret.n_cols; c++) {
    m2.col[c].full(col);
    for (int r = 0; r < ret.n_rows; r++)
      ret.col[c].set_new(r, m1.col[r] * col);
  }

  return ret;
}

template <class T>
Vec<T> trans_mult(const Sparse_Mat<T> &m, const Vec<T> &v)
{
  Vec<T> r(m.n_cols);
  for (int c = 0; c < m.n_cols; c++)
    r(c) = m.col[c] * v;

  return r;
}

template <class T>
Sparse_Mat<T> mult_trans(const Sparse_Mat<T> &m1, const Sparse_Mat<T> &m2)
{
  return trans_mult(m1.transpose(), m2.transpose());
}

template <class T>
inline Sparse_Mat<T> sparse(const Mat<T> &m, T epsilon)
{
  Sparse_Mat<T> s(m, epsilon);
  return s;
}

template <class T>
inline Mat<T> full(const Sparse_Mat<T> &s)
{
  Mat<T> m;
  s.full(m);
  return m;
}

template <class T>
inline Sparse_Mat<T> transpose(const Sparse_Mat<T> &s)
{
  Sparse_Mat<T> m;
  s.transpose(m);
  return m;
}


// ---------------------------------------------------------------------
// Instantiations
// ---------------------------------------------------------------------

ITPP_EXPORT_TEMPLATE template class ITPP_EXPORT Sparse_Mat<int>;
ITPP_EXPORT_TEMPLATE template class ITPP_EXPORT Sparse_Mat<double>;
ITPP_EXPORT_TEMPLATE template class ITPP_EXPORT Sparse_Mat<std::complex<double> >;

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_imat operator+(const sparse_imat &, const sparse_imat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_mat operator+(const sparse_mat &, const sparse_mat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_cmat operator+(const sparse_cmat &, const sparse_cmat &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_imat operator*(const sparse_imat &, const sparse_imat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_mat operator*(const sparse_mat &, const sparse_mat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_cmat operator*(const sparse_cmat &, const sparse_cmat &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT ivec operator*(const ivec &, const sparse_imat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT vec operator*(const vec &, const sparse_mat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT cvec operator*(const cvec &, const sparse_cmat &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT ivec operator*(const sparse_imat &, const ivec &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT vec operator*(const sparse_mat &, const vec &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT cvec operator*(const sparse_cmat &, const cvec &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT imat trans_mult(const sparse_imat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT mat trans_mult(const sparse_mat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT cmat trans_mult(const sparse_cmat &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_imat trans_mult_s(const sparse_imat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_mat trans_mult_s(const sparse_mat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_cmat trans_mult_s(const sparse_cmat &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_imat trans_mult(const sparse_imat &, const sparse_imat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_mat trans_mult(const sparse_mat &, const sparse_mat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_cmat trans_mult(const sparse_cmat &, const sparse_cmat &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT ivec trans_mult(const sparse_imat &, const ivec &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT vec trans_mult(const sparse_mat &, const vec &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT cvec trans_mult(const sparse_cmat &, const cvec &);

ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_imat mult_trans(const sparse_imat &, const sparse_imat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_mat mult_trans(const sparse_mat &, const sparse_mat &);
ITPP_EXPORT_TEMPLATE template ITPP_EXPORT sparse_cmat mult_trans(const sparse_cmat &, const sparse_cmat &);


} // namespace itpp

#endif // #ifndef SMAT_H