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 "spring-spacer.hh"
  12 #include "debug.hh"
  13 #include "paper-column.hh"
  14 #include "paper-score.hh"
  15 #include "paper-def.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_prebroken_piece (RIGHT));
  90           line.top () =  dynamic_cast<Paper_column*>(line.top ()->find_prebroken_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           ( (Break_algorithm*)this)->approx_stats_.add (approx.cols_);
 103           approx.approximate_solve_line ();
 104
 105           if  (approx.energy_f_  > energy_bound_f_)
 106             {
 107               continue;
 108             }
 109
 110
 111           // this is a likely candidate. Store it.
 112           candidate_lines.push (approx);
 113           candidates.push (start_idx);
 114         }
 115
 116
 117       int minimal_j = -1;
 118       Real minimal_energy = infinity_f;
 119       for (int j=0; j < candidates.size (); j++)
 120         {
 121           int start = candidates[j];
 122           if (optimal_paths[start].line_config_.energy_f_
 123                + candidate_lines[j].energy_f_  > minimal_energy)
 124
 125             continue;
 126
 127           if (!candidate_lines[j].satisfies_constraints_b_)
 128             {
 129               candidate_lines[j].solve_line ();
 130               ( (Break_algorithm*)this)->exact_stats_.add (candidate_lines[j].cols_);
 131             }
 132
 133           Real this_energy
 134             = optimal_paths[start].line_config_.energy_f_
 135             + candidate_lines[j].energy_f_ ;
 136
 137           if (this_energy < minimal_energy)
 138             {
 139               minimal_j = j;
 140               minimal_energy = this_energy;
 141             }
 142         }
 143
 144       if (minimal_j < 0)
 145         {
 146           optimal_paths[break_idx].prev_break_i_ = -1;
 147           optimal_paths[break_idx].line_config_.energy_f_ = infinity_f;
 148         }
 149       else
 150         {
 151           optimal_paths[break_idx].prev_break_i_ = candidates[minimal_j];
 152           optimal_paths[break_idx].line_config_ = candidate_lines[minimal_j];
 153           optimal_paths[break_idx].line_i_ =
 154             optimal_paths[optimal_paths[break_idx].prev_break_i_].line_i_ + 1;
 155         }
 156
 157       if (! (break_idx % HAPPY_DOTS_I))
 158         *mlog << "[" << break_idx << "]" << flush;
 159
 160       spacer_p_list.junk ();
 161     }
 162
 163   if  (break_idx % HAPPY_DOTS_I)
 164     *mlog << "[" << break_idx << "]" << flush;
 165
 166   Array<int> final_breaks;
 167
 168   Array<Column_x_positions> lines;
 169
 170   /* skip 0-th element, since it is a "dummy" elt*/
 171   for (int i = optimal_paths.size ()-1; i> 0;)
 172     {
 173       final_breaks.push (i);
 174       assert (i > optimal_paths[i].prev_break_i_);
 175
 176       // there was no "feasible path"
 177       if (!optimal_paths[i].line_config_.config_.size ()) {
 178         final_breaks.set_size (0);
 179         break;
 180       }
 181       i = optimal_paths[i].prev_break_i_;
 182     }
 183
 184
 185   for (int i= final_breaks.size (); i--;)
 186     lines.push (optimal_paths[final_breaks[i]].line_config_);
 187
 188   return lines;
 189 }
 190
 191
 192 Gourlay_breaking::Gourlay_breaking ()
 193 {
 194   energy_bound_f_ = infinity_f;
 195   max_measures_i_ = INT_MAX;
 196 }
 197
 198 void
 199 Gourlay_breaking::do_set_pscore ()
 200 {
 201   energy_bound_f_ = pscore_l_->paper_l_->get_var ("gourlay_energybound");
 202   max_measures_i_ =int (rint (pscore_l_->paper_l_->get_var ("gourlay_maxmeasures")));
 203 }
 204