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 "colhpos.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   int line_i_;
  32   Real energy_f_;
  33   Column_x_positions line_config_;
  34   Break_node ()
  35   {
  36     prev_break_i_ = -1;
  37     line_i_ = 0;
  38   }
  39 };
  40
  41 /**
  42   This algorithms is adapted from the OSU Tech report on breaking lines.
  43
  44  */
  45
  46 Array<Column_x_positions>
  47 Gourlay_breaking::do_solve () const
  48 {
  49   Array<Break_node> optimal_paths;
  50   Line_of_cols all = pscore_l_->col_l_arr_ ;
  51   Array<int> breaks = find_break_indices ();
  52
  53   optimal_paths.set_size (breaks.size ());
  54
  55   Break_node first_node ;
  56   first_node.prev_break_i_ = -1;
  57   first_node.line_config_.energy_f_ = 0;
  58   first_node.line_i_ = 0;
  59
  60   optimal_paths[0] = first_node;
  61   int break_idx=1;
  62
  63
  64   for (; break_idx< breaks.size (); break_idx++)
  65     {
  66       Array<int> candidates;
  67       Array<Column_x_positions> candidate_lines;
  68       Cons_list<Line_spacer> spacer_p_list;
  69
  70       /*
  71         start with a short line, add measures. At some point
  72         the line becomes infeasible. Then we don't try to add more
  73         */
  74       for (int start_idx = break_idx; start_idx--;)
  75         {
  76           if  (break_idx - start_idx > max_measures_i_)
  77             break;
  78
  79           if (optimal_paths[start_idx].prev_break_i_ < 0
  80               && optimal_paths[start_idx].line_config_.energy_f_)
  81
  82             continue;
  83
  84           Line_of_cols line = all.slice (breaks[start_idx], breaks[break_idx]+1);
  85
  86           line[0] = dynamic_cast<Paper_column*>(line[0]->find_prebroken_piece (RIGHT));
  87           line.top () =  dynamic_cast<Paper_column*>(line.top ()->find_prebroken_piece (LEFT));
  88
  89           if (!feasible (line))
  90             break;
  91
  92           Column_x_positions approx;
  93           approx.cols = line;
  94
  95           approx.spacer_l_ = generate_spacing_problem (line,
  96             pscore_l_->paper_l_->line_dimensions_int (optimal_paths[start_idx].line_i_));
  97           spacer_p_list.append (new Killing_cons<Line_spacer> (approx.spacer_l_,0));
  98
  99           ( (Break_algorithm*)this)->approx_stats_.add (approx.cols);
 100           approx.approximate_solve_line ();
 101
 102           if  (approx.energy_f_  > energy_bound_f_)
 103             {
 104               continue;
 105             }
 106
 107
 108           // this is a likely candidate. Store it.
 109           candidate_lines.push (approx);
 110           candidates.push (start_idx);
 111         }
 112
 113
 114       int minimal_j = -1;
 115       Real minimal_energy = infinity_f;
 116       for (int j=0; j < candidates.size (); j++)
 117         {
 118           int start = candidates[j];
 119           if (optimal_paths[start].line_config_.energy_f_
 120                + candidate_lines[j].energy_f_  > minimal_energy)
 121
 122             continue;
 123
 124           if (!candidate_lines[j].satisfies_constraints_b_)
 125             {
 126               candidate_lines[j].solve_line ();
 127               ( (Break_algorithm*)this)->exact_stats_.add (candidate_lines[j].cols);
 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 << "]" << flush;
 162
 163   Array<int> final_breaks;
 164
 165   Array<Column_x_positions> lines;
 166
 167   /* skip 0-th element, since it is a "dummy" elt*/
 168   for (int i = optimal_paths.size ()-1; i> 0;)
 169     {
 170       final_breaks.push (i);
 171       assert (i > optimal_paths[i].prev_break_i_);
 172
 173       // there was no "feasible path"
 174       if (!optimal_paths[i].line_config_.config.size ()) {
 175         final_breaks.set_size (0);
 176         break;
 177       }
 178       i = optimal_paths[i].prev_break_i_;
 179     }
 180
 181
 182   for (int i= final_breaks.size (); i--;)
 183     lines.push (optimal_paths[final_breaks[i]].line_config_);
 184
 185   return lines;
 186 }
 187
 188
 189 Gourlay_breaking::Gourlay_breaking ()
 190 {
 191   get_line_spacer = Spring_spacer::constructor;
 192   energy_bound_f_ = infinity_f;
 193   max_measures_i_ = INT_MAX;
 194 }
 195
 196 void
 197 Gourlay_breaking::do_set_pscore ()
 198 {
 199   energy_bound_f_ = pscore_l_->paper_l_->get_var ("gourlay_energybound");
 200   max_measures_i_ =int (rint (pscore_l_->paper_l_->get_var ("gourlay_maxmeasures")));
 201 }
 202