Negative cycle-canceling: Difference between revisions

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(Created page with "== Abstract view == '''Algorithmic problem:''' Min-cost flow problem '''Type of algorithm:''' loop '''Invariant:''' The flow is feasible. '''Variant:''' The cost of th...")
 
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'''Variant:''' The cost of the flow decreases.
'''Variant:''' The cost of the flow decreases.


''Definition:'''
'''Definition:'''
A cycle is '''negative''' if the sum of the cost values on all of its arcs is negative.
A cycle is '''negative''' if the sum of the cost values on all of its arcs is negative.



Revision as of 04:36, 22 October 2014

Abstract view

Algorithmic problem: Min-cost flow problem

Type of algorithm: loop

Invariant: The flow is feasible.

Variant: The cost of the flow decreases.

Definition: A cycle is negative if the sum of the cost values on all of its arcs is negative.

Break condition: There is no more negative cycle in the residual network.

Induction basis

Abstract view: Start with an arbitrary feasible flow, for example, the zero flow.

Induction step

Abstract view:

  1. Find a cycle of negative cost in the residual network.
  2. Augme