gauss.hpp

Go to the documentation of this file.

// Copyright 1996-2005  Michael E. Stillman
#ifndef _gauss_hh_
#define _gauss_hh_

 
#include "relem.hpp"
#include "matrix.hpp"
#include "polyring.hpp"
#include "comp-gb.hpp"
 
struct gm_elem : public our_new_delete
{
  gm_elem *next;
  int nterms;
  vec f;
  vec fsyz;
};

class GaussElimComputation : public GBComputation
{
 private:
  int row;
  gm_elem **reduce_list;  // One list for each row
  gm_elem **gb_list;      // The GB elem (if any) with the given row index
                          // as lead term.
 
  const Ring *R;       // Ring of 'gens'.  Should be a field.
  const Matrix *gens;  // This is the input
  const FreeModule *Fsyz;
  VECTOR(vec) syz_list;
 
  int n_gb;
  int n_pairs, n_syz;
 
  int collect_syz;  // 0 or 1
  int n_comps_per_syz;
 
 private:
  gm_elem *new_gen(int i);
  void remove_gm_elem(gm_elem *&p);
  void insert(gm_elem *p);
 
  void reduce(gm_elem *&p, gm_elem *q);
  void reduce(vec &f, vec &fsyz, bool tail_only = false);
  void reduce(vec &f);
 
 protected:
  virtual bool stop_conditions_ok() { return true; }
 public:
  // An honest GB computation
  GaussElimComputation(const Matrix *m, int collect_syz, int n_syz);
  ~GaussElimComputation();
 
  virtual void remove_gb() {}
  virtual void start_computation();
 
  virtual int complete_thru_degree() const;
  // The computation is complete up through this degree.
 
  virtual const Ring *get_ring() const { return R; }
  // Results of the computation //
  virtual const Matrix /* or null */ *get_gb();
 
  virtual const Matrix /* or null */ *get_mingens();
 
  virtual const Matrix /* or null */ *get_change();
 
  virtual const Matrix /* or null */ *get_syzygies();
 
  virtual const Matrix /* or null */ *get_initial(int nparts);

  // Normal forms and lifting ////
 
  virtual const Matrix /* or null */ *matrix_remainder(const Matrix *m);
 
  virtual M2_bool matrix_lift(const Matrix *m,
                              const Matrix /* or null */ **result_remainder,
                              const Matrix /* or null */ **result_quotient);
 
  virtual int contains(const Matrix *m);

  // Statistics and spair information //
 
  virtual void text_out(buffer &o) const;
  // This displays statistical information, and depends on the
  // M2_gbTrace value.
};
#endif
 
// Local Variables:
// compile-command: "make -C $M2BUILDDIR/Macaulay2/e "
// indent-tabs-mode: nil
// End: