home *** CD-ROM | disk | FTP | other *** search
/ NetNews Usenet Archive 1992 #18 / NN_1992_18.iso / spool / comp / theory / 1772 < prev    next >
Encoding:
Text File  |  1992-08-17  |  1.9 KB  |  44 lines
  1. Newsgroups: comp.theory
  2. Path: sparky!uunet!munnari.oz.au!uniwa!cujo!leonardo!shillsp
  3. From: shillsp@leonardo.cs.curtin.edu.au (Stephen Hill)
  4. Subject: Linear programming HELP REQUIRED!
  5. Message-ID: <shillsp.714123640@marsh>
  6. Keywords: linear programming
  7. Sender: news@cujo.curtin.edu.au (News Manager)
  8. Organization: Curtin University of Technology
  9. Date: Tue, 18 Aug 1992 07:40:40 GMT
  10. Lines: 32
  11.  
  12.  
  13.  
  14. Currently I am working on the Vehicle Routing Problem under
  15. Capacity constraints. I am using a cutting planes technique
  16. to get lower bounds which are then incorporated
  17. in a branch and bound technique. I have programmed
  18. the dual and revised simplex with upper bounds, using an LU
  19. decomposition to solve equations involving the basis, and these both
  20. work for problems with around 450 variables and 50 constraints.
  21.  
  22. With larger problems I encounter numerical instability and cannot
  23. get a solution.
  24.  
  25. I am looking for ways to get rid of this problem. Alternatively I am
  26. willing to purchase a linear programming package, either commercial
  27. or otherwise (to run on a Sun SPARC station 2) or working source code
  28. which I can incorporate into my own code. 
  29.  
  30. I hope that someone out there can provide me with references, advice or
  31. code. Thanks in advance. 
  32.  
  33. ------------------------------------------------------------------------------
  34.                  Stephen Hill- shillsp@euler.cs.curtin.edu.au                  
  35.  
  36.                  Curtin University, Perth, Western Australia                  
  37. ------------------------------------------------------------------------------
  38. --
  39. ------------------------------------------------------------------------------
  40.                  Stephen Hill- shillsp@euler.cs.curtin.edu.au                  
  41.                                                                                 
  42.                  Elvis: Too young to die, too fat to live!                     
  43. ------------------------------------------------------------------------------
  44.