Results 1 to 2 of 2

Math Help - Primal to dual problem

  1. #1
    Newbie
    Joined
    Mar 2012
    Posts
    24

    Primal to dual problem

    So I'm trying to solve a linear programming problem but there is just something I keep missing.
    The primal problem:
    x1 + 2x2 + 3x3 + 3x4 <= 15000
    2x1 + 4x2 + x4 + 3x4 <= 20000
    3x1 + 2x2 + 5x3 + 3x4 <= 20000
    x1 >= 1000
    x2 >= 1000
    Maximize x1 + x2 + 2x3 + 2x4. I know the optimal value is 10500 as I've solved it.

    But now I'm trying to create a dual problem.
    y1 + 2y2 + 3y3 + y4 >= 1
    2y1 + 4y2 + 2y3 + y5 >= 1
    3y1 + y2 + 5y3 >= 2
    3y1 + 3y2 + 3y3 >= 2
    Minimize 15000y1 + 20000y2 + 20000y3 + 1000y4 + 1000y5.
    And this cannot be right. So what's wrong with it? Solving it using the dual simplex method doesn't result in the same optimization value as the primal problem hence I'm doing something wrong when formulating the dual problem...
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Mar 2012
    Posts
    24

    Re: Primal to dual problem

    I mean, it is effectively a 90 degree rotation?
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Primal/Dual Linear Program problem (Minimum cost critical pa
    Posted in the Advanced Applied Math Forum
    Replies: 0
    Last Post: March 2nd 2010, 12:23 PM
  2. Dual-Primal / Simplex
    Posted in the Advanced Applied Math Forum
    Replies: 2
    Last Post: August 12th 2009, 06:42 AM
  3. I need help for primal and dual problems
    Posted in the Advanced Math Topics Forum
    Replies: 0
    Last Post: January 31st 2009, 02:15 PM
  4. The Dual Problem??
    Posted in the Advanced Algebra Forum
    Replies: 0
    Last Post: December 10th 2007, 09:39 AM
  5. Need Help please!!!! Primal/Dual problems
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: November 4th 2007, 09:54 PM

Search Tags


/mathhelpforum @mathhelpforum