static public void Test()
{
BitVector S1 = 0b0011_0010;
BitVector S2 = 0b0100_0011;
Debug.Assert(SetOp.Union(S1, S2) == 0b0111_0011);
Debug.Assert(SetOp.Union(S1, S2) == SetOp.Union(S2, S1));
Debug.Assert(SetOp.Intersect(S1, S2) == 0b0000_0010);
Debug.Assert(SetOp.Intersect(S1, S2) == SetOp.Intersect(S2, S1));
Debug.Assert(SetOp.Substract(S1, S2) == 0b0011_0000);
Debug.Assert(SetOp.Substract(S2, S1) == 0b0100_0001);
Debug.Assert(SetOp.CountSetBits(S1) == 3);
Debug.Assert(SetOp.MinTableIndex(S1) == 1);
Debug.Assert(SetOp.MinTableIndex(S2) == 0);
Debug.Assert(SetOp.OrderBeforeSet(3) == 15);
var l = SetOp.TablesAscending(S2).ToList();
Debug.Assert(l.SequenceEqual(new List <int>()
{
0, 1, 6
}));
l = SetOp.TablesDescending(S2).ToList();
Debug.Assert(l.SequenceEqual(new List <int>()
{
6, 1, 0
}));
}
static internal string ToString(BitVector S)
{
string r = "";
foreach (var t in SetOp.TablesAscending(S))
{
r += t + ", ";
}
return(r);
}
// given a set of tables, returns the set of its neighbours
BitVector Neighbours(BitVector S)
{
BitVector result = 0;
int ntables = vertices_.Count;
foreach (var t in SetOp.TablesAscending(S))
{
foreach (var n in NeighboursOf(t))
{
result |= (long)(1 << n);
}
}
return(result);
}
// extra a subgraph for the given nodes set S
// (1) we shall also remove both uncovered nodes and edges
// (2) make this as fast as possible as it is tightly tested in
// DP_bushy algorithm
//
// say we have
// A - B - C
// \ D
// SubGraph(ABD) => {A-D and non-connected node C}.
//
internal JoinGraph SubGraph(BitVector S)
{
var subvert = new List <LogicNode>();
var subtablelist = SetOp.TablesAscending(S).ToList();
foreach (var t in subtablelist)
{
subvert.Add(vertices_[t]);
}
var subjoins = new List <Expr>();
foreach (var j in preds_)
{
var i12 = ParseJoinPredExpr(j);
int i1 = i12[0], i2 = i12[1];
if (subtablelist.Contains(i1) && subtablelist.Contains(i2))
{
subjoins.Add(j);
}
}
return(new JoinGraph(subvert, subjoins));
}