public void Step()
{
if (State == SimplexState.FirstPhase || State == SimplexState.SecondPhase)
{
Arc current = EnteringArcEnumerator.Current;
Arc arc = Arc.Invalid;
double num = double.NaN;
bool flag = false;
do
{
Arc current2 = EnteringArcEnumerator.Current;
if (!Tree.ContainsKey(current2))
{
bool flag2 = Saturated.Contains(current2);
double num2 = ActualCost(current2) - (Potential[MyGraph.V(current2)] - Potential[MyGraph.U(current2)]);
if ((num2 < 0.0 - Epsilon && !flag2) || (num2 > Epsilon && (flag2 || ActualLowerBound(current2) == -9223372036854775808L)))
{
arc = current2;
num = num2;
flag = flag2;
break;
}
}
if (!EnteringArcEnumerator.MoveNext())
{
EnteringArcEnumerator = MyGraph.Arcs(ArcFilter.All).GetEnumerator();
EnteringArcEnumerator.MoveNext();
}
}while (!(EnteringArcEnumerator.Current == current));
if (arc == Arc.Invalid)
{
if (State == SimplexState.FirstPhase)
{
State = SimplexState.SecondPhase;
foreach (Arc artificialArc in ArtificialArcs)
{
if (Flow(artificialArc) > 0)
{
State = SimplexState.Infeasible;
break;
}
}
if (State == SimplexState.SecondPhase)
{
RecalculatePotentialDfs recalculatePotentialDfs = new RecalculatePotentialDfs();
recalculatePotentialDfs.Parent = this;
recalculatePotentialDfs.Run(TreeSubgraph, null);
}
}
else
{
State = SimplexState.Optimal;
}
}
else
{
Node node = MyGraph.U(arc);
Node node2 = MyGraph.V(arc);
List <Arc> list = new List <Arc>();
List <Arc> list2 = new List <Arc>();
IPath path = TreeSubgraph.FindPath(node2, node, Dfs.Direction.Undirected);
foreach (Node item in path.Nodes())
{
Arc arc2 = path.NextArc(item);
((!(MyGraph.U(arc2) == item)) ? list2 : list).Add(arc2);
}
ulong num3 = (!(num < 0.0)) ? MySubtract(Flow(arc), ActualLowerBound(arc)) : MySubtract(ActualUpperBound(arc), Flow(arc));
Arc arc3 = arc;
bool flag3 = !flag;
foreach (Arc item2 in list)
{
ulong num4 = (!(num < 0.0)) ? MySubtract(Tree[item2], ActualLowerBound(item2)) : MySubtract(ActualUpperBound(item2), Tree[item2]);
if (num4 < num3)
{
num3 = num4;
arc3 = item2;
flag3 = (num < 0.0);
}
}
foreach (Arc item3 in list2)
{
ulong num5 = (!(num > 0.0)) ? MySubtract(Tree[item3], ActualLowerBound(item3)) : MySubtract(ActualUpperBound(item3), Tree[item3]);
if (num5 < num3)
{
num3 = num5;
arc3 = item3;
flag3 = (num > 0.0);
}
}
long num6 = 0L;
switch (num3)
{
case ulong.MaxValue:
State = SimplexState.Unbounded;
return;
default:
num6 = (long)((!(num < 0.0)) ? (0L - num3) : num3);
foreach (Arc item4 in list)
{
Dictionary <Arc, long> tree;
Arc key;
(tree = Tree)[key = item4] = tree[key] + num6;
}
foreach (Arc item5 in list2)
{
Dictionary <Arc, long> tree;
Arc key2;
(tree = Tree)[key2 = item5] = tree[key2] - num6;
}
break;
case 0uL:
break;
}
if (arc3 == arc)
{
if (flag)
{
Saturated.Remove(arc);
}
else
{
Saturated.Add(arc);
}
}
else
{
Tree.Remove(arc3);
TreeSubgraph.Enable(arc3, false);
if (flag3)
{
Saturated.Add(arc3);
}
double num7 = ActualCost(arc) - (Potential[node2] - Potential[node]);
if (num7 != 0.0)
{
UpdatePotentialDfs updatePotentialDfs = new UpdatePotentialDfs();
updatePotentialDfs.Parent = this;
updatePotentialDfs.Diff = num7;
updatePotentialDfs.Run(TreeSubgraph, new Node[1]
{
node2
});
}
Tree[arc] = Flow(arc) + num6;
if (flag)
{
Saturated.Remove(arc);
}
TreeSubgraph.Enable(arc, true);
}
}
}
}
/// Performs an iteration in the simplex algorithm.
/// Modifies the State field according to what happened.
public void Step()
{
if (State != SimplexState.FirstPhase && State != SimplexState.SecondPhase)
{
return;
}
// calculate reduced costs and find an entering arc
Arc firstArc = EnteringArcEnumerator.Current;
Arc enteringArc = Arc.Invalid;
double enteringReducedCost = double.NaN;
bool enteringSaturated = false;
while (true)
{
Arc arc = EnteringArcEnumerator.Current;
if (!Tree.ContainsKey(arc))
{
bool saturated = Saturated.Contains(arc);
double reducedCost = ActualCost(arc) - (Potential[MyGraph.V(arc)] - Potential[MyGraph.U(arc)]);
if ((reducedCost < -Epsilon && !saturated) ||
(reducedCost > Epsilon && (saturated || ActualLowerBound(arc) == long.MinValue)))
{
enteringArc = arc;
enteringReducedCost = reducedCost;
enteringSaturated = saturated;
break;
}
}
// iterate
if (!EnteringArcEnumerator.MoveNext())
{
EnteringArcEnumerator = MyGraph.Arcs().GetEnumerator();
EnteringArcEnumerator.MoveNext();
}
if (EnteringArcEnumerator.Current == firstArc)
{
break;
}
}
if (enteringArc == Arc.Invalid)
{
if (State == SimplexState.FirstPhase)
{
State = SimplexState.SecondPhase;
foreach (var arc in ArtificialArcs)
{
if (Flow(arc) > 0)
{
State = SimplexState.Infeasible;
break;
}
}
if (State == SimplexState.SecondPhase)
{
new RecalculatePotentialDfs()
{
Parent = this
}
}