lily/mixed-qp.cc

   1 /*
   2   qlp.cc -- implement Mixed_qp
   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 "debug.hh"
  10 #include "qlp.hh"
  11
  12
  13 void
  14 Mixed_qp::add_equality_cons (Vector , double)
  15 {
  16   assert (false);
  17 }
  18
  19 void
  20 Mixed_qp::add_fixed_var (int i, Real r)
  21 {
  22   eq_cons.push (i);
  23   eq_consrhs.push (r);
  24 }
  25
  26
  27 /**
  28   eliminate appropriate variables, until we have a Ineq_constrained_qp
  29   then solve that.
  30
  31   PRE
  32   cons should be ascending
  33   */
  34 Vector
  35 Mixed_qp::solve (Vector start) const
  36 {
  37   if (!dim())
  38     return Vector (0);
  39
  40   print();
  41   Ineq_constrained_qp pure (*this);
  42
  43   for  (int i= eq_cons.size()-1; i>=0; i--)
  44     {
  45       pure.eliminate_var (eq_cons[i], eq_consrhs[i]);
  46       start.del (eq_cons[i]);
  47     }
  48   Vector sol = pure.solve (start);
  49   for (int i= 0; i < eq_cons.size(); i++)
  50     {
  51       sol.insert (eq_consrhs[i],eq_cons[i]);
  52     }
  53   return sol;
  54 }
  55
  56
  57 Mixed_qp::Mixed_qp (int n)
  58   : Ineq_constrained_qp (n)
  59 {
  60 }
  61
  62 void
  63 Mixed_qp::OK() const
  64 {
  65 #ifndef NDEBUG
  66   Ineq_constrained_qp::OK();
  67   assert (eq_consrhs.size() == eq_cons.size ());
  68 #endif
  69 }
  70
  71 void
  72 Mixed_qp::print() const
  73 {
  74 #ifndef NPRINT
  75   Ineq_constrained_qp::print();
  76   for (int i=0; i < eq_cons.size(); i++)
  77     {
  78       DOUT << "eq cons "<<i<<": x["<<eq_cons[i]<<"] == " << eq_consrhs[i]<< '\n';
  79     }
  80 #endif
  81 }
  82