Method propagate

gecode/int/linear/int-dom.hpp:390–476

  template<class Val, class View>
  ExecStatus
  DomEq<Val,View>::propagate(Space& home, const ModEventDelta& med) {
    if (View::me(med) != ME_INT_DOM) {
      ExecStatus es = prop_bnd<Val,View,View>(home,med,*this,x,y,c);
      GECODE_ES_CHECK(es);
      return home.ES_FIX_PARTIAL(*this,View::med(ME_INT_DOM));
    }

    // Value of equation for partial assignment
    Val d = -c;

    int n = x.size();
    int m = y.size();

    Region r;
    // Create support-base iterators
    PosSupportIter<Val>* xp = r.alloc<PosSupportIter<Val> >(n);
    NegSupportIter<Val>* yp = r.alloc<NegSupportIter<Val> >(m);

    // Initialize views for assignments
    {
      Val l = 0;
      Val u = 0;
      for (int j=m; j--; ) {
        yp[j].init(r,-y[j].scale(),y[j].base(),l,u);
        l += y[j].max(); u += y[j].min();
      }
      for (int i=n; i--; ) {
        xp[i].init(r,x[i].scale(),x[i].base(),l,u);
        l -= x[i].min(); u -= x[i].max();
      }
    }

    // Collect support information by iterating assignments
    {
      // Force reset of all iterators in first round
      int i = 0;
      int j = 0;

    next_i:
      // Reset all iterators for positive views and update d
      while (i<n) {
        if (!xp[i].reset(d)) goto prev_i;
        i++;
      }
    next_j:
      // Reset all iterators for negative views and update d
      while (j<m) {
        if (!yp[j].reset(d)) goto prev_j;
        j++;
      }
      // Check whether current assignment is solution
      if (d == 0) {
        // Record support
        for (int is=0; is<n; is++) xp[is].support();
        for (int js=0; js<m; js++) yp[js].support();
      }
    prev_j: