shadow price of the constraints

[ruoshuili-cn]

Hi maintainers,

I created an Lp instance in PuLP and have obtained a feasible solution, but I as try to use "constraint.pi" to get the shadow price, i.e. the dual variable's value of a constraint, the value seems not correct. I also noticed that as I changed the order of adding constraints, the value of shadow prices also change accordingly, which confused me a lot.

Can I know more about how the ".pi" function works and what might cause unstable shadow price values?

I've used both Python 2 and 3 to run the model, both results are not correct. I'm using a Windows64-bit.

Thanks!

[pchtsp]

Can you please provide an example? Check the docs on how to do that: https://coin-or.github.io/pulp/guides/how_to_debug.html#giving-feedback-and-asking-for-help

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On Sat, Jan 16, 2021, 15:04 ruoshuili-cn ***@***.***> wrote: Hi maintainers, I created an Lp instance in PuLP and have obtained a *feasible* solution, but I as try to use "constraint.pi" to get the shadow price, i.e. the dual variable's value of a constraint, the value seems not correct. I also noticed that as I changed the order of adding constraints, the value of shadow prices also change accordingly, which confused me a lot. *Can I know more about how the ".pi" function works and what might cause unstable shadow price values?* I've used both Python 2 and 3 to run the model, both results are not correct. I'm using a Windows64-bit. Thanks! — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#391>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABJUZ44KJHFE2LM6GLQW273S2GMHVANCNFSM4WFJFODQ> .