data SVal = SVal { match :: Int} deriving (Eq, Show)

bipartitematching g = 
  let init v = SVal(-1);
      ss0 v = SVal(if (vid v`mod`2 == 0 && val v.^match == -1)
                   then random (-1) [ vid u | (e,u) <- is v, val u .^ match == -1 ]
                   else val v.^match);
      ss1 v = SVal(if (vid v`mod`2 == 1 && val v.^match == -1) 
                   then random (-1) [ vid u | (e,u) <- is v, val u .^ match == vid v ]
                   else val v.^match);
      ss2 v = SVal(if (vid v`mod`2 == 0 && val v.^match /= -1) 
                   then random (-1) [ vid u | (e,u) <- is v, val u .^ match == vid v ] 
                   else val v.^match); 
      step g = let g1 = gmap ss0 g;
                   g2 = gmap ss1 g1;
                   g3 = gmap ss2 g2
               in g3
  in giter init step Fix g


{-
data BM = BM { match :: Int } deriving (Eq, Show)
bimatch g = 
  let init v = BM (-1);
      ss0 v = BM (if (vid v`mod`2 == 0 && val v.^match == -1) then random (-1) [ vid u | (e,u) <- is v, val u.^match == -1 ] else val v.^match);
      ss1 v = BM (if (vid v`mod`2 == 1 && val v.^match == -1) then random (-1) [ vid u | (e,u)<-is v, val u.^match == vid v ] else val v.^match);
      ss2 v = BM (if (vid v`mod`2 == 0 && val v.^match /= -1) then random (-1) [ vid u | (e,u)<-is v, val u.^match == vid v ] else val v.^match);
      step g = let g1 = gmap ss0 g;
                   g2 = gmap ss1 g1;
                   g3 = gmap ss2 g2
               in g3
  in giter init step Fix g

 -}