COIN-OR::LEMON - Graph Library

Opened 10 years ago

Closed 10 years ago

#291 closed defect (fixed)

Problems with the GEQ/LEQ supply type in NetworkSimplex

Reported by: Peter Kovacs Owned by: Peter Kovacs
Priority: critical Milestone: LEMON 1.1 release
Component: core Version: hg main
Keywords: Cc:
Revision id:

Description

There are some problems with the handling of the GEQ/LEQ supply type in NetworkSimplex.

  1. The current version of the optimality conditions for these cases are not sufficient. We should also expect that all node potentials are non-positive (GEQ type) or non-negative (LEQ type).
  2. The initialization of the algorithm (artificial arcs and initial basis) is not correct for these inequality cases if we also have negative costs.
  3. Using LEQ and GEQ type we have to allow some of the artificial arcs to get into the basis again after they were removed.

Attachments (2)

291-ns-fixes-e239cde7ae57.patch (29.0 KB) - added by Peter Kovacs 10 years ago.
291-ns-test-0d9a1b26810a.patch (7.2 KB) - added by Peter Kovacs 10 years ago.

Download all attachments as: .zip

Change History (4)

Changed 10 years ago by Peter Kovacs

Changed 10 years ago by Peter Kovacs

comment:1 Changed 10 years ago by Peter Kovacs

Status: newassigned

[e239cde7ae57] solves all these problems, [0d9a1b26810a] improves the test file.

comment:2 Changed 10 years ago by Peter Kovacs

Resolution: fixed
Status: assignedclosed

They went to the main branch with sligthly modified doc, see [8b0df68370a4] and [cc61d09f053b].

Note: See TracTickets for help on using tickets.