lily/gourlay-breaking.cc

   1 /*
   2   gourlay-breaking.cc -- implement Gourlay_breaking
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--1999 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9 #include "gourlay-breaking.hh"
  10 #include "column-x-positions.hh"
  11 #include "debug.hh"
  12 #include "paper-column.hh"
  13 #include "paper-score.hh"
  14 #include "paper-def.hh"
  15 #include "line-spacer.hh"
  16
  17 #include "killing-cons.tcc"
  18
  19 /// How often to print operator pacification marks?
  20 const int HAPPY_DOTS_I = 3;
  21
  22 /**
  23   Helper to trace back an optimal path
  24  */
  25 struct Break_node {
  26   /** this was the previous. If negative, this break should not be
  27     considered: this path has infinite energy
  28
  29     */
  30   int prev_break_i_;
  31   /**
  32      Which system number so far?
  33    */
  34   int line_i_;
  35
  36   Real energy_f_;
  37   Column_x_positions line_config_;
  38
  39   Break_node ()
  40   {
  41     prev_break_i_ = -1;
  42     line_i_ = 0;
  43   }
  44 };
  45
  46 /**
  47   This algorithms is adapted from the OSU Tech report on breaking lines.
  48  */
  49 Array<Column_x_positions>
  50 Gourlay_breaking::do_solve () const
  51 {
  52   Array<Break_node> optimal_paths;
  53   Line_of_cols all = pscore_l_->col_l_arr_ ;
  54   Array<int> breaks = find_break_indices ();
  55
  56   optimal_paths.set_size (breaks.size ());
  57
  58   Break_node first_node ;
  59   first_node.prev_break_i_ = -1;
  60   first_node.line_config_.energy_f_ = 0;
  61   first_node.line_i_ = 0;
  62
  63   optimal_paths[0] = first_node;
  64   int break_idx=1;
  65
  66   for (; break_idx< breaks.size (); break_idx++)
  67     {
  68       Array<int> candidates;
  69       Array<Column_x_positions> candidate_lines;
  70       Cons_list<Line_spacer> spacer_p_list;
  71
  72       /*
  73         start with a short line, add measures. At some point
  74         the line becomes infeasible. Then we don't try to add more
  75         */
  76       for (int start_idx = break_idx; start_idx--;)
  77         {
  78           if  (break_idx - start_idx > max_measures_i_)
  79             break;
  80
  81           if (optimal_paths[start_idx].prev_break_i_ < 0
  82               && optimal_paths[start_idx].line_config_.energy_f_)
  83             continue;
  84
  85
  86
  87           Line_of_cols line = all.slice (breaks[start_idx], breaks[break_idx]+1);
  88
  89           line[0] = dynamic_cast<Paper_column*>(line[0]->find_broken_piece (RIGHT));
  90           line.top () =  dynamic_cast<Paper_column*>(line.top ()->find_broken_piece (LEFT));
  91
  92           if (!feasible (line))
  93             break;
  94
  95           Column_x_positions approx;
  96           approx.cols_ = line;
  97
  98           approx.spacer_l_ = generate_spacing_problem (line,
  99             pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_));
 100           spacer_p_list.append (new Killing_cons<Line_spacer> (approx.spacer_l_,0));
 101
 102           approx.approximate_solve_line ();
 103
 104           if  (approx.energy_f_  > energy_bound_f_)
 105             {
 106               continue;
 107             }
 108
 109           // this is a likely candidate. Store it.
 110           candidate_lines.push (approx);
 111           candidates.push (start_idx);
 112         }
 113
 114
 115       int minimal_j = -1;
 116       Real minimal_energy = infinity_f;
 117       for (int j=0; j < candidates.size (); j++)
 118         {
 119           int start = candidates[j];
 120           if (optimal_paths[start].line_config_.energy_f_
 121                + candidate_lines[j].energy_f_  > minimal_energy)
 122
 123             continue;
 124
 125           if (!candidate_lines[j].satisfies_constraints_b_)
 126             {
 127               candidate_lines[j].solve_line ();
 128             }
 129
 130           Real this_energy
 131             = optimal_paths[start].line_config_.energy_f_
 132             + candidate_lines[j].energy_f_ ;
 133
 134           if (this_energy < minimal_energy)
 135             {
 136               minimal_j = j;
 137               minimal_energy = this_energy;
 138             }
 139         }
 140
 141       if (minimal_j < 0)
 142         {
 143           optimal_paths[break_idx].prev_break_i_ = -1;
 144           optimal_paths[break_idx].line_config_.energy_f_ = infinity_f;
 145         }
 146       else
 147         {
 148           optimal_paths[break_idx].prev_break_i_ = candidates[minimal_j];
 149           optimal_paths[break_idx].line_config_ = candidate_lines[minimal_j];
 150           optimal_paths[break_idx].line_i_ =
 151             optimal_paths[optimal_paths[break_idx].prev_break_i_].line_i_ + 1;
 152         }
 153
 154       if (! (break_idx % HAPPY_DOTS_I))
 155         *mlog << "[" << break_idx << "]" << flush;
 156
 157       spacer_p_list.junk ();
 158     }
 159
 160   if  (break_idx % HAPPY_DOTS_I)
 161     *mlog << "[" << break_idx << "]";
 162
 163   *mlog << endl;
 164
 165   Array<int> final_breaks;
 166
 167   Array<Column_x_positions> lines;
 168
 169   /* skip 0-th element, since it is a "dummy" elt*/
 170   for (int i = optimal_paths.size ()-1; i> 0;)
 171     {
 172       final_breaks.push (i);
 173       assert (i > optimal_paths[i].prev_break_i_);
 174
 175       // there was no "feasible path"
 176       if (!optimal_paths[i].line_config_.config_.size ()) {
 177         final_breaks.set_size (0);
 178         break;
 179       }
 180       i = optimal_paths[i].prev_break_i_;
 181     }
 182
 183
 184   for (int i= final_breaks.size (); i--;)
 185     lines.push (optimal_paths[final_breaks[i]].line_config_);
 186
 187   return lines;
 188 }
 189
 190
 191 Gourlay_breaking::Gourlay_breaking ()
 192 {
 193   energy_bound_f_ = infinity_f;
 194   max_measures_i_ = INT_MAX;
 195 }
 196
 197 void
 198 Gourlay_breaking::do_set_pscore ()
 199 {
 200   energy_bound_f_ = pscore_l_->paper_l_->get_var ("gourlay_energybound");
 201   max_measures_i_ =int (rint (pscore_l_->paper_l_->get_var ("gourlay_maxmeasures")));
 202 }
 203