Originally posted by: Nasaku

Hello;

I need to do a re-optimization on my model after adding a new constraint. My problem is that I need to add a contraint that include my slacks variables.

How can I do it ? in my model, i can use only normal variables (not slack variables), or may be there is a method that i don't know it.

I need help, i'm stopped for one week in this point.

Thanks

For a constraint a*x<=b the slack s is defined as s=b-a*x. So when you define a constraint on s then you just have to substitute b-a*x in the constraint.

Originally posted by: Nasaku

Hello,

Thanks for response. I have thinking in this issue, but i'm prefering to do it directely to use dual simplex after.

So, if i add my constraint by replacing "s" by "b-a*x", can i guarantee to do a re-optimization from the last table of simplex and not doing a new optimization from the beginning of the problem ?

Thanks for help

Originally posted by: Nasaku

I found the answer in this link :

https://www.ibm.com/developerworks/community/forums/html/topic?id=75458d70-ae5a-49e2-a5d5-fc5f77be7f32

thanks