// Template sparse classes
/*

Copyright (C) 2004-2011 David Bateman
Copyright (C) 1998-2004 Andy Adler
Copyright (C) 2010 VZLU Prague

This file is part of Octave.

Octave is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

Octave is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with Octave; see the file COPYING.  If not, see
<http://www.gnu.org/licenses/>.

*/

#if !defined (octave_Sparse_h)
#define octave_Sparse_h 1

#include <cassert>
#include <cstddef>

#include <iosfwd>
#include <algorithm>

#include "Array.h"
#include "dim-vector.h"
#include "lo-error.h"
#include "lo-utils.h"

#include "oct-sort.h"
#include "oct-mem.h"

class idx_vector;

// Two dimensional sparse class.  Handles the reference counting for
// all the derived classes.

template <class T>
class
Sparse
{
public:

  typedef T element_type;

protected:
  //--------------------------------------------------------------------
  // The real representation of all Sparse arrays.
  //--------------------------------------------------------------------

  class OCTAVE_API SparseRep
  {
  public:

    T *d;
    octave_idx_type *r;
    octave_idx_type *c;
    octave_idx_type nzmx;
    octave_idx_type nrows;
    octave_idx_type ncols;
    octave_refcount<int> count;

    SparseRep (void) : d (0), r (0), c (new octave_idx_type [1]), nzmx (0), nrows (0),
                       ncols (0), count (1) { c[0] = 0; }

    SparseRep (octave_idx_type n) : d (0), r (0), c (new octave_idx_type [n+1]), nzmx (0), nrows (n),
      ncols (n), count (1)
      {
        for (octave_idx_type i = 0; i < n + 1; i++)
          c[i] = 0;
      }

    SparseRep (octave_idx_type nr, octave_idx_type nc) : d (0), r (0), c (new octave_idx_type [nc+1]), nzmx (0),
      nrows (nr), ncols (nc), count (1)
      {
        for (octave_idx_type i = 0; i < nc + 1; i++)
          c[i] = 0;
      }

    SparseRep (octave_idx_type nr, octave_idx_type nc, octave_idx_type nz) : d (new T [nz]),
      r (new octave_idx_type [nz]), c (new octave_idx_type [nc+1]), nzmx (nz), nrows (nr),
      ncols (nc), count (1)
      {
        for (octave_idx_type i = 0; i < nc + 1; i++)
          c[i] = 0;
      }

    SparseRep (const SparseRep& a)
      : d (new T [a.nzmx]), r (new octave_idx_type [a.nzmx]), c (new octave_idx_type [a.ncols + 1]),
      nzmx (a.nzmx), nrows (a.nrows), ncols (a.ncols), count (1)
      {
        octave_idx_type nz = a.nnz ();
        copy_or_memcpy (nz, a.d, d);
        copy_or_memcpy (nz, a.r, r);
        copy_or_memcpy (ncols + 1, a.c, c);
      }

    ~SparseRep (void) { delete [] d; delete [] r; delete [] c; }

    octave_idx_type length (void) const { return nzmx; }

    octave_idx_type nnz (void) const { return c [ncols]; }

    T& elem (octave_idx_type _r, octave_idx_type _c);

    T celem (octave_idx_type _r, octave_idx_type _c) const;

    T& data (octave_idx_type i) { return d[i]; }

    T cdata (octave_idx_type i) const { return d[i]; }

    octave_idx_type& ridx (octave_idx_type i) { return r[i]; }

    octave_idx_type cridx (octave_idx_type i) const { return r[i]; }

    octave_idx_type& cidx (octave_idx_type i) { return c[i]; }

    octave_idx_type ccidx (octave_idx_type i) const { return c[i]; }

    void maybe_compress (bool remove_zeros);

    void change_length (octave_idx_type nz);

    bool indices_ok (void) const;

  private:

    // No assignment!

    SparseRep& operator = (const SparseRep& a);
  };

  //--------------------------------------------------------------------

  void make_unique (void)
    {
      if (rep->count > 1)
        {
          --rep->count;
          rep = new SparseRep (*rep);
        }
    }

public:

  // !!! WARNING !!! -- these should be protected, not public.  You
  // should not access these data members directly!

  typename Sparse<T>::SparseRep *rep;

  dim_vector dimensions;

private:

  typename Sparse<T>::SparseRep *nil_rep (void) const
    {
      static typename Sparse<T>::SparseRep *nr
        = new typename Sparse<T>::SparseRep ();

      nr->count++;

      return nr;
    }

public:

  Sparse (void)
    : rep (nil_rep ()), dimensions (dim_vector(0,0)) { }

  explicit Sparse (octave_idx_type n)
    : rep (new typename Sparse<T>::SparseRep (n)),
      dimensions (dim_vector (n, n)) { }

  explicit Sparse (octave_idx_type nr, octave_idx_type nc)
    : rep (new typename Sparse<T>::SparseRep (nr, nc)),
      dimensions (dim_vector (nr, nc)) { }

  explicit Sparse (octave_idx_type nr, octave_idx_type nc, T val);

  Sparse (const dim_vector& dv, octave_idx_type nz)
    : rep (new typename Sparse<T>::SparseRep (dv(0), dv(1), nz)),
    dimensions (dv) { }

  Sparse (octave_idx_type nr, octave_idx_type nc, octave_idx_type nz)
    : rep (new typename Sparse<T>::SparseRep (nr, nc, nz)),
      dimensions (dim_vector (nr, nc)) { }

  // Type conversion case. Preserves capacity ().
  template <class U>
  Sparse (const Sparse<U>& a)
    : rep (new typename Sparse<T>::SparseRep (a.rep->nrows, a.rep->ncols, a.rep->nzmx)),
    dimensions (a.dimensions)
    {
      octave_idx_type nz = a.nnz ();
      std::copy (a.rep->d, a.rep->d + nz, rep->d);
      copy_or_memcpy (nz, a.rep->r, rep->r);
      copy_or_memcpy (rep->ncols + 1, a.rep->c, rep->c);
    }

  // No type conversion case.
  Sparse (const Sparse<T>& a)
    : rep (a.rep), dimensions (a.dimensions)
    {
      rep->count++;
    }

public:

  Sparse (const dim_vector& dv);

  Sparse (const Sparse<T>& a, const dim_vector& dv);

  Sparse (const Array<T>& a, const idx_vector& r, const idx_vector& c,
          octave_idx_type nr = -1, octave_idx_type nc = -1,
          bool sum_terms = true, octave_idx_type nzm = -1);

  // Sparsify a normal matrix
  Sparse (const Array<T>& a);

  virtual ~Sparse (void);

  Sparse<T>& operator = (const Sparse<T>& a);

  // Note that nzmax and capacity are the amount of storage for
  // non-zero elements, while nnz is the actual number of non-zero
  // terms.
  octave_idx_type nzmax (void) const { return rep->length (); }
  octave_idx_type capacity (void) const { return nzmax (); }
  octave_idx_type nnz (void) const { return rep->nnz (); }

  // Querying the number of elements (incl. zeros) may overflow the index type,
  // so don't do it unless you really need it.
  octave_idx_type numel (void) const
    {
      return dimensions.safe_numel ();
    }

  octave_idx_type nelem (void) const { return capacity (); }
  octave_idx_type length (void) const { return numel (); }

  octave_idx_type dim1 (void) const { return dimensions(0); }
  octave_idx_type dim2 (void) const { return dimensions(1); }

  octave_idx_type rows (void) const { return dim1 (); }
  octave_idx_type cols (void) const { return dim2 (); }
  octave_idx_type columns (void) const { return dim2 (); }

  octave_idx_type get_row_index (octave_idx_type k) { return ridx (k); }
  octave_idx_type get_col_index (octave_idx_type k)
    {
      octave_idx_type ret = 0;
      while (cidx(ret+1) < k)
        ret++;
      return ret;
    }

  size_t byte_size (void) const
    {
      return (static_cast<size_t>(cols () + 1) * sizeof (octave_idx_type)
              + static_cast<size_t> (capacity ()) * (sizeof (T) + sizeof (octave_idx_type)));
    }

  dim_vector dims (void) const { return dimensions; }

  Sparse<T> squeeze (void) const { return *this; }

  octave_idx_type compute_index (const Array<octave_idx_type>& ra_idx) const;

  T range_error (const char *fcn, octave_idx_type n) const;
  T& range_error (const char *fcn, octave_idx_type n);

  T range_error (const char *fcn, octave_idx_type i, octave_idx_type j) const;
  T& range_error (const char *fcn, octave_idx_type i, octave_idx_type j);

  T range_error (const char *fcn, const Array<octave_idx_type>& ra_idx) const;
  T& range_error (const char *fcn, const Array<octave_idx_type>& ra_idx);

  // No checking, even for multiple references, ever.

  T& xelem (octave_idx_type n)
    {
      octave_idx_type i = n % rows (), j = n / rows();
      return xelem (i, j);
    }

  T xelem (octave_idx_type n) const
    {
      octave_idx_type i = n % rows (), j = n / rows();
      return xelem (i, j);
    }

  T& xelem (octave_idx_type i, octave_idx_type j) { return rep->elem (i, j); }
  T xelem (octave_idx_type i, octave_idx_type j) const { return rep->celem (i, j); }

  T& xelem (const Array<octave_idx_type>& ra_idx)
    { return xelem (compute_index (ra_idx)); }

  T xelem (const Array<octave_idx_type>& ra_idx) const
    { return xelem (compute_index (ra_idx)); }

  // FIXME -- would be nice to fix this so that we don't
  // unnecessarily force a copy, but that is not so easy, and I see no
  // clean way to do it.

  T& checkelem (octave_idx_type n)
    {
      if (n < 0 || n >= numel ())
        return range_error ("T& Sparse<T>::checkelem", n);
      else
        {
          make_unique ();
          return xelem (n);
        }
    }

  T& checkelem (octave_idx_type i, octave_idx_type j)
    {
      if (i < 0 || j < 0 || i >= dim1 () || j >= dim2 ())
        return range_error ("T& Sparse<T>::checkelem", i, j);
      else
        {
          make_unique ();
          return xelem (i, j);
        }
    }

  T& checkelem (const Array<octave_idx_type>& ra_idx)
    {
      octave_idx_type i = compute_index (ra_idx);

      if (i < 0)
        return range_error ("T& Sparse<T>::checkelem", ra_idx);
      else
        return elem (i);
    }

  T& elem (octave_idx_type n)
    {
      make_unique ();
      return xelem (n);
    }

  T& elem (octave_idx_type i, octave_idx_type j)
    {
      make_unique ();
      return xelem (i, j);
    }

  T& elem (const Array<octave_idx_type>& ra_idx)
    { return Sparse<T>::elem (compute_index (ra_idx)); }

#if defined (BOUNDS_CHECKING)
  T& operator () (octave_idx_type n) { return checkelem (n); }
  T& operator () (octave_idx_type i, octave_idx_type j) { return checkelem (i, j); }
  T& operator () (const Array<octave_idx_type>& ra_idx) { return checkelem (ra_idx); }
#else
  T& operator () (octave_idx_type n) { return elem (n); }
  T& operator () (octave_idx_type i, octave_idx_type j) { return elem (i, j); }
  T& operator () (const Array<octave_idx_type>& ra_idx) { return elem (ra_idx); }
#endif

  T checkelem (octave_idx_type n) const
    {
      if (n < 0 || n >= numel ())
        return range_error ("T Sparse<T>::checkelem", n);
      else
        return xelem (n);
    }

  T checkelem (octave_idx_type i, octave_idx_type j) const
    {
      if (i < 0 || j < 0 || i >= dim1 () || j >= dim2 ())
        return range_error ("T Sparse<T>::checkelem", i, j);
      else
        return xelem (i, j);
    }

  T checkelem (const Array<octave_idx_type>& ra_idx) const
    {
      octave_idx_type i = compute_index (ra_idx);

      if (i < 0)
        return range_error ("T Sparse<T>::checkelem", ra_idx);
      else
        return Sparse<T>::elem (i);
    }

  T elem (octave_idx_type n) const { return xelem (n); }

  T elem (octave_idx_type i, octave_idx_type j) const { return xelem (i, j); }

  T elem (const Array<octave_idx_type>& ra_idx) const
    { return Sparse<T>::elem (compute_index (ra_idx)); }

#if defined (BOUNDS_CHECKING)
  T operator () (octave_idx_type n) const { return checkelem (n); }
  T operator () (octave_idx_type i, octave_idx_type j) const { return checkelem (i, j); }
  T operator () (const Array<octave_idx_type>& ra_idx) const { return checkelem (ra_idx); }
#else
  T operator () (octave_idx_type n) const { return elem (n); }
  T operator () (octave_idx_type i, octave_idx_type j) const { return elem (i, j); }
  T operator () (const Array<octave_idx_type>& ra_idx) const { return elem (ra_idx); }
#endif

  Sparse<T> maybe_compress (bool remove_zeros = false)
    {
      if (remove_zeros)
        make_unique (); // Needs to unshare because elements are removed.

      rep->maybe_compress (remove_zeros);
      return (*this);
    }

  Sparse<T> reshape (const dim_vector& new_dims) const;

  Sparse<T> permute (const Array<octave_idx_type>& vec, bool inv = false) const;

  Sparse<T> ipermute (const Array<octave_idx_type>& vec) const
    { return permute (vec, true); }

  void resize1 (octave_idx_type n);

  void resize (octave_idx_type r, octave_idx_type c);

  void resize (const dim_vector& dv);

  void change_capacity (octave_idx_type nz)
    {
      if (nz < nnz ())
        make_unique (); // Unshare now because elements will be truncated.
      rep->change_length (nz);
    }

  Sparse<T>& insert (const Sparse<T>& a, octave_idx_type r, octave_idx_type c);
  Sparse<T>& insert (const Sparse<T>& a, const Array<octave_idx_type>& idx);

  bool is_square (void) const { return (dim1 () == dim2 ()); }

  bool is_empty (void) const { return (rows () < 1 && cols () < 1); }

  Sparse<T> transpose (void) const;

  T* data (void) { make_unique (); return rep->d; }
  T& data (octave_idx_type i) { make_unique (); return rep->data (i); }
  T* xdata (void) { return rep->d; }
  T& xdata (octave_idx_type i) { return rep->data (i); }

  T data (octave_idx_type i) const { return rep->data (i); }
  // FIXME -- shouldn't this be returning const T*?
  T* data (void) const { return rep->d; }

  octave_idx_type* ridx (void) { make_unique (); return rep->r; }
  octave_idx_type& ridx (octave_idx_type i) { make_unique (); return rep->ridx (i); }
  octave_idx_type* xridx (void) { return rep->r; }
  octave_idx_type& xridx (octave_idx_type i) { return rep->ridx (i); }

  octave_idx_type ridx (octave_idx_type i) const { return rep->cridx (i); }
  // FIXME -- shouldn't this be returning const octave_idx_type*?
  octave_idx_type* ridx (void) const { return rep->r; }

  octave_idx_type* cidx (void) { make_unique (); return rep->c; }
  octave_idx_type& cidx (octave_idx_type i) { make_unique (); return rep->cidx (i); }
  octave_idx_type* xcidx (void) { return rep->c; }
  octave_idx_type& xcidx (octave_idx_type i) { return rep->cidx (i); }

  octave_idx_type cidx (octave_idx_type i) const { return rep->ccidx (i); }
  // FIXME -- shouldn't this be returning const octave_idx_type*?
  octave_idx_type* cidx (void) const { return rep->c; }

  octave_idx_type ndims (void) const { return dimensions.length (); }

  void delete_elements (const idx_vector& i);

  void delete_elements (int dim, const idx_vector& i);

  void delete_elements (const idx_vector& i, const idx_vector& j);

  Sparse<T> index (const idx_vector& i, bool resize_ok = false) const;

  Sparse<T> index (const idx_vector& i, const idx_vector& j, bool resize_ok = false) const;

  void assign (const idx_vector& i, const Sparse<T>& rhs);

  void assign (const idx_vector& i, const idx_vector& j, const Sparse<T>& rhs);

  void print_info (std::ostream& os, const std::string& prefix) const;

  // Unsafe.  These functions exist to support the MEX interface.
  // You should not use them anywhere else.
  void *mex_get_data (void) const { return const_cast<T *> (data ()); }

  octave_idx_type *mex_get_ir (void) const { return const_cast<octave_idx_type *> (ridx ()); }

  octave_idx_type *mex_get_jc (void) const { return const_cast<octave_idx_type *> (cidx ()); }

  Sparse<T> sort (octave_idx_type dim = 0, sortmode mode = ASCENDING) const;
  Sparse<T> sort (Array<octave_idx_type> &sidx, octave_idx_type dim = 0,
                 sortmode mode = ASCENDING) const;

  Sparse<T> diag (octave_idx_type k = 0) const;

  // dim = -1 and dim = -2 are special; see Array<T>::cat description.
  static Sparse<T>
  cat (int dim, octave_idx_type n, const Sparse<T> *sparse_list);

  Array<T> array_value (void) const;

  template <class U, class F>
  Sparse<U>
  map (F fcn) const
  {
    Sparse<U> result;
    U f_zero = fcn (0.);

    if (f_zero != 0.)
      {
        octave_idx_type nr = rows ();
        octave_idx_type nc = cols ();

        result = Sparse<U> (nr, nc, f_zero);

        for (octave_idx_type j = 0; j < nc; j++)
          for (octave_idx_type i = cidx(j); i < cidx (j+1); i++)
            {
              octave_quit ();
              /* Use data instead of elem for better performance.  */
              result.data (ridx (i) + j * nr) = fcn (data(i));
            }

        result.maybe_compress (true);
      }
    else
      {
        octave_idx_type nz = nnz ();
        octave_idx_type nr = rows ();
        octave_idx_type nc = cols ();

        result = Sparse<U> (nr, nc, nz);
        octave_idx_type ii = 0;
        result.cidx (ii) = 0;

        for (octave_idx_type j = 0; j < nc; j++)
          {
            for (octave_idx_type i = cidx(j); i < cidx (j+1); i++)
              {
                U val = fcn (data (i));
                if (val != 0.0)
                  {
                    result.data (ii) = val;
                    result.ridx (ii++) = ridx (i);
                  }
                octave_quit ();
              }
            result.cidx (j+1) = ii;
          }

        result.maybe_compress (false);
      }

    return result;
  }

  // Overloads for function references.
  template <class U>
  Sparse<U>
  map (U (&fcn) (T)) const
  { return map<U, U (&) (T)> (fcn); }

  template <class U>
  Sparse<U>
  map (U (&fcn) (const T&)) const
  { return map<U, U (&) (const T&)> (fcn); }

  bool indices_ok (void) const { return rep->indices_ok (); }
};

template<typename T>
std::istream&
read_sparse_matrix (std::istream& is, Sparse<T>& a,
                    T (*read_fcn) (std::istream&))
{
  octave_idx_type nr = a.rows ();
  octave_idx_type nc = a.cols ();
  octave_idx_type nz = a.nzmax ();

  if (nr > 0 && nc > 0)
    {
      octave_idx_type itmp;
      octave_idx_type jtmp;
      octave_idx_type iold = 0;
      octave_idx_type jold = 0;
      octave_idx_type ii = 0;
      T tmp;

      a.cidx (0) = 0;
      for (octave_idx_type i = 0; i < nz; i++)
        {
          itmp = 0; jtmp = 0;
          is >> itmp;
          itmp--;

          is >> jtmp;
          jtmp--;

          if (itmp < 0 || itmp >= nr)
            {
              (*current_liboctave_error_handler)
                ("invalid sparse matrix: row index = %d out of range",
                 itmp + 1);
              is.setstate (std::ios::failbit);
              goto done;
            }

          if (jtmp < 0 || jtmp >= nc)
            {
              (*current_liboctave_error_handler)
                ("invalid sparse matrix: column index = %d out of range",
                 jtmp + 1);
              is.setstate (std::ios::failbit);
              goto done;
            }

          if (jtmp < jold)
            {
              (*current_liboctave_error_handler)
                ("invalid sparse matrix: column indices must appear in ascending order");
              is.setstate (std::ios::failbit);
              goto done;
            }
          else if (jtmp > jold)
            {
              for (octave_idx_type j = jold; j < jtmp; j++)
                a.cidx(j+1) = ii;
            }
          else if (itmp < iold)
            {
              (*current_liboctave_error_handler)
                ("invalid sparse matrix: row indices must appear in ascending order in each column");
              is.setstate (std::ios::failbit);
              goto done;
            }

          iold = itmp;
          jold = jtmp;

          tmp = read_fcn (is);

          if (is)
            {
              a.data (ii) = tmp;
              a.ridx (ii++) = itmp;
            }
          else
            goto done;
        }

      for (octave_idx_type j = jold; j < nc; j++)
        a.cidx(j+1) = ii;
    }

 done:

  return is;
}

#endif
