### final phase: contract all nodes with negative score (CEdges - Deleted)
# 
# to be called from a master script such as ContractionK

if isDBObject("NContracted") then delete NContracted endif

let NContracted = 1


while (NContracted > 0) do
{
update NContracted := "NodesX" mfeedpq
  extend[ 
    In: pwrap("EdgesX_Target") pwrap("EdgesX") mexactmatch[.Node] count, 
    Out: pwrap("EdgesX_Source") pwrap("EdgesX") mexactmatch[.Node] count] 
  extend[CEdges: fun(t: TUPLE)
      pwrap("EdgesX_Target") pwrap("EdgesX") mexactmatch[attr(t, Node)] 
        sortby[Source, Cost] krdup[Source] {i} 
      pwrap("EdgesX_Source") pwrap("EdgesX") mexactmatch[attr(t, Node)] 
        sortby[Target, Cost] krdup[Target] {o} 
      product 
      filter[.Source_i # .Target_o] 
      filter[ ( fun(node: int) pwrap("EdgesX_Source") pwrap("EdgesX") 
        mexactmatch[node] ) 
        minPathCost1[Target, .Source_i, .Target_o, Cost, 4] >= (.Cost_i + .Cost_o)]
      groupby[; Added: fun(g: GROUP) ifthenelse(g count <= (attr(t, In) + attr(t, Out)),
        g feed
        projectextend[; Source: .Source_i, Target: .Target_o, 
          SourcePos: .SourcePos_i, TargetPos: .TargetPos_o,
              Cost: .Cost_i + .Cost_o, Middle: attr(t, Node), 
              NEdges: .NEdges_i + .NEdges_o] 
        minsert[pwrap("EdgesX")] 
        minsertavltree[pwrap("EdgesX_Source"), Source] 
        minsertavltree[pwrap("EdgesX_Target"), Target] remove[TID] 
        minsert[pwrap("ContractionX")] count,
        -10)]
      extractDef[Added, 0]
  ]
  filter[.CEdges >= 0]
  extend[Deleted: 
      pwrap("EdgesX_Target") pwrap("EdgesX") mexactmatch[.Node] 
      pwrap("EdgesX_Source") pwrap("EdgesX") mexactmatch[.Node] 
      concat mblock pwrap("EdgesX") mdeletedirect 
      mdeleteavltree[pwrap("EdgesX_Target"), Target] 
      mdeleteavltree[pwrap("EdgesX_Source"), Source] 
      count
  ]
#  printstream
  minsert[pwrap("DeletedNodes")]
  count
|
query memdelete("NodesX")
|
query 
  "EdgesX" mfeed project[Source, SourcePos] renameattr[Node: Source, Pos: SourcePos] 
  "EdgesX" mfeed project[Target, TargetPos] renameattr[Node: Target, Pos: TargetPos] concat sort rdup 
  extend[Prio: 0.0] 
  mcreatepqueue[Prio, "NodesX"] count
}
endwhile