Method EFPA

examples/efpa.cpp:127–274

Actual model

public:
  /// Actual model
  EFPA(const EFPAOptions& opt)
    : Script(opt),
      v(opt.v()),
      q(opt.q()),
      l(opt.l()),
      d(opt.d()),
      n(q*l),
      nseqpair((v*(v-1))/2),
      c(*this, n*v, 1,q),
      diff(*this, n*nseqpair, 0, 1)
  {
    // Matrix access
    // q*lambda=n columns, and v rows
    Matrix<IntVarArray> cm(c, n, v);
    // q*lambda=n columns, and nseqpair rows
    Matrix<BoolVarArray> diffm(diff, n, nseqpair);

    // Counting symbols in rows
    {
      IntArgs values(q);
      for (int i = q; i--; ) values[i] = i+1;
      IntSet cardinality(l, l);
      for (int i = v; i--; )
        count(*this, cm.row(i), cardinality, values, opt.ipl());
    }

    // Difference variables
    {
      int nseqi = 0;
      for (int a = 0; a < v; ++a) {
        for (int b = a+1; b < v; ++b) {
          for (int i = n; i--; ) {
            rel(*this, cm(i, a), IRT_NQ, cm(i, b), diffm(i, nseqi));
          }
          ++nseqi;
        }
      }
      assert(nseqi == nseqpair);
    }

    // Counting the Hamming difference
    {
      for (int i = nseqpair; i--; ) {
        linear(*this, diffm.row(i), IRT_EQ, d);
      }
    }

    // Symmetry breaking
    if (opt.symmetry()) {
      IntRelType row_less = d==0 ? IRT_EQ : IRT_LE;
      // order rows
      for (int r = 0; r<v-1; ++r) {
        rel(*this, cm.row(r), row_less, cm.row(r+1));
      }
      // order columns
      for (int c = 0; c<n-1; ++c) {
        rel(*this, cm.col(c), IRT_LQ, cm.col(c+1));
      }