mipgen.hh

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/*
 *  Copyright 2007 Martin von Gagern
 *
 *
 *  This file is part of mqn2mps.
 *
 *  mqn2mps 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.
 *
 *  mqn2mps 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#ifndef MIPGEN_HH
#define MIPGEN_HH

/**
 * @file
 * Interface of class mipgen.
 */

class driver;

/**
 * The mipgen class generates a Mixed Integer Program.
 * It is the base class for other output format drivers.
 *
 * @section order Order of problem data
 *
 * @subsection rows Order of Rows
 * In the final form, the problem description will contain these rows:
 *  -# one row @c _MaxOrder restricting the number of fields which are
 *     part of any solution
 *  -# two rows for gamma selection if driver::gamma_constraint is set
 *  -# one row for each constraint specified in the input file
 *  -# rows for difference vectors from mipgen::collect_fields()
 *
 * These rows are all represented in mipgen::row_names,
 * mipgen::row_bounds and mipgen::matrix, but not in
 * mipgen::constraints which contains only the input sonstraints.
 *
 * @subsection cols Order of Columns
 * In the final form, the problem description will contain these
 * columns:
 *  -# one column for gamma selection from mipgen::append_gamma()
 *     if driver::gamma_constraint is set, otherwise omitted
 *  -# modulo arithmetic columns from mipgen::modfields()
 *  -# difference vectors from mipgen::collect_fields()
 *  -# original input fields from driver::fields
 *
 * These columns are all represented in mipgen::col_names,
 * mipgen::col_bounds and mipgen::matrix as well as mipgen::fields.
 *
 */
class mipgen {
public:
  mipgen(const driver& d);
  virtual ~mipgen();
  void formulate();
  virtual void write(const char* filename);

protected:

  /**
   * Reference to the driver.
   * This allows access to command line options and input data.
   */
  const driver& drv;

  /**
   * Number of generated columns.
   *
   * Columns used to express modulo arithmetic, but also some other
   * generated columns, preceed the actual %field descriptions in the
   * matrix. This number gives an indication as to how many generated
   * columns there are, and thus allows different handling of the
   * different types of columns without relying on the special naming
   * convention that a generated column starts with an underscore.
   */
  size_t modcount;

  /**
   * Column data.
   *
   * As the description of class field explains, a field is a colum
   * description, including a name, the matrix elements of this
   * column, and a pair of bounds on the variable associated with this
   * column. This list contains original field descriptions from the
   * input file, but preceding them there are generated columns.
   *
   * @see @ref cols
   */
  std::vector<field> fields;

  /**
   * Row descriptions.
   *
   * This is a direct copy of driver::constraints at first and
   * restricts most operations to the field components which are
   * actually constrained in some way. In the final output, only these
   * components will be included as rows, along with some special
   * rows.
   *
   * Preceding the equality constrained rows corresponding to these
   * constraints, there will be one generated row for the maximum
   * order, and—if enabled—two rows for gamma selection. These are not
   * represented as constraint objects and thus not part of this
   * list.
   *
   * @see @ref rows
   */
  std::vector<constraint> constraints;

  /**
   * A list of column names.
   * This is copied from the names of the mipgen::constraints by
   * mipgen::copy_col_names. They are intended for easy output
   * generation in derived classes.
   */
  std::vector<std::string> col_names;

  /**
   * A list of row names.
   * This is copied from the names of the mipgen::fields by
   * mipgen::copy_row_names, except for some special rows.
   * They are intended for easy output generation in derived classes.
   */
  std::vector<std::string> row_names;

  /**
   * A list of column bounds.
   * These bounds on the variables are set by mipgen::set_bounds.
   * They are intended for easy output generation in derived classes.
   */
  std::vector<bounds> col_bounds;

  /**
   * A list of row bounds.
   * These bounds on the row values are set by mipgen::set_bounds.
   * They are intended for easy output generation in derived classes.
   */
  std::vector<bounds> row_bounds;

  /**
   * The final matrix elements.
   * A list of list is used to represent the final integral
   * two-dimensional matrix of coefficients of the integer program.
   * They are intended for easy output generation in derived classes.
   */
  std::vector< std::vector<int> > matrix;

  virtual void make_matrix(size_t rows, size_t cols);
  virtual void set_element(size_t row, size_t col, int val);
  virtual void fill_matrix();
  virtual void write(std::ostream& out);
  static int realmod(int a, int b);

private:

  /**
   * Map row number to field component index.
   * The rows in the output mostly correspond to mipgen::constraints,
   * which identify the corresponding quantum number by name.
   * The order of elements in the field::values might therefore be
   * different from the output order. This vector gives the
   * corresponding indices into field::values in order of output
   * rows.
   */
  std::vector<int> indices;

  void modfields();
  void multiply_k();
  void append_gamma();
  void comdenom();
  void get_indices();
  void set_bounds();
  void copy_row_names();
  void collect_fields();
  void copy_col_names();
  void unique_names(std::vector<std::string>& names);
};

#endif // ifndef MIPGEN_HH

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