lily/qlp.cc

   1 /*
   2   qlp.cc -- implement Mixed_qp
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997 Han-Wen Nienhuys <hanwen@stack.nl>
   7 */
   8
   9 #include "debug.hh"
  10 #include "qlp.hh"
  11
  12 void
  13 Mixed_qp::add_equality_cons (Vector , double)
  14 {
  15   assert (false);
  16 }
  17
  18 void
  19 Mixed_qp::add_fixed_var (int i, Real r)
  20 {
  21   eq_cons.push (i);
  22   eq_consrhs.push (r);
  23 }
  24
  25
  26 /**
  27   eliminate appropriate variables, until we have a Ineq_constrained_qp
  28   then solve that.
  29
  30   PRE
  31   cons should be ascending
  32   */
  33 Vector
  34 Mixed_qp::solve (Vector start) const
  35 {
  36   if (!dim())
  37     return Vector (0);
  38
  39   print();
  40   Ineq_constrained_qp pure (*this);
  41
  42   for  (int i= eq_cons.size()-1; i>=0; i--)
  43     {
  44       pure.eliminate_var (eq_cons[i], eq_consrhs[i]);
  45       start.del (eq_cons[i]);
  46     }
  47   Vector sol = pure.solve (start);
  48   for (int i= 0; i < eq_cons.size(); i++)
  49     {
  50       sol.insert (eq_consrhs[i],eq_cons[i]);
  51     }
  52   return sol;
  53 }
  54
  55
  56 void
  57 Ineq_constrained_qp::assert_solution (Vector sol) const
  58 {
  59   Array<int> binding;
  60   for (int i=0; i < cons.size(); i++)
  61     {
  62       Real R=cons[i] * sol- consrhs[i];
  63       assert (R> -EPS);
  64       if (R < EPS)
  65         binding.push (i);
  66     }
  67   // KKT check...
  68   // todo
  69 }
  70
  71 void
  72 Ineq_constrained_qp::print() const
  73 {
  74 #ifndef NPRINT
  75   DOUT << "Quad " << quad;
  76   DOUT << "lin " << lin <<"\n"
  77        << "const " << const_term<<"\n";
  78   for (int i=0; i < cons.size(); i++)
  79     {
  80       DOUT << "constraint["<<i<<"]: " << cons[i] << " >= " << consrhs[i];
  81       DOUT << "\n";
  82     }
  83 #endif
  84 }
  85
  86 Mixed_qp::Mixed_qp (int n)
  87   : Ineq_constrained_qp (n)
  88 {
  89 }
  90
  91 void
  92 Mixed_qp::OK() const
  93 {
  94 #ifndef NDEBUG
  95   Ineq_constrained_qp::OK();
  96   assert (eq_consrhs.size() == eq_cons.size ());
  97 #endif
  98 }
  99
 100 void
 101 Mixed_qp::print() const
 102 {
 103 #ifndef NPRINT
 104   Ineq_constrained_qp::print();
 105   for (int i=0; i < eq_cons.size(); i++)
 106     {
 107       DOUT << "eq cons "<<i<<": x["<<eq_cons[i]<<"] == " << eq_consrhs[i]<<"\n";
 108     }
 109 #endif
 110 }
 111