Method BIBD

examples/bibd.cpp:107–143

Actual model

  /// Actual model
  BIBD(const BIBDOptions& o)
    : Script(o), opt(o), _p(*this,opt.v*opt.b,0,1) {
    Matrix<BoolVarArray> p(_p,opt.b,opt.v);

    // r ones per row
    for (int i=0; i<opt.v; i++)
      linear(*this, p.row(i), IRT_EQ, opt.r);

    // k ones per column
    for (int j=0; j<opt.b; j++)
      linear(*this, p.col(j), IRT_EQ, opt.k);

    // Exactly lambda ones in scalar product between two different rows
    for (int i1=0; i1<opt.v; i1++)
      for (int i2=i1+1; i2<opt.v; i2++) {
        BoolVarArgs row(opt.b);
        for (int j=0; j<opt.b; j++)
          row[j] = expr(*this, p(j,i1) && p(j,i2));
        linear(*this, row, IRT_EQ, opt.lambda);
      }

    if (opt.symmetry() == SYMMETRY_LDSB) {
      Symmetries s;
      s << rows_interchange(p);
      s << columns_interchange(p);
      branch(*this, _p, BOOL_VAR_NONE(), BOOL_VAL_MIN(), s);
    } else {
      if (opt.symmetry() == SYMMETRY_LEX) {
        for (int i=1; i<opt.v; i++)
          rel(*this, p.row(i-1), IRT_GQ, p.row(i));
        for (int j=1; j<opt.b; j++)
          rel(*this, p.col(j-1), IRT_GQ, p.col(j));
      }
      branch(*this, _p, BOOL_VAR_NONE(), BOOL_VAL_MIN());
    }

  }

  /// Print solution
  virtual void