[Help-glpk] [Fwd: help to get dual solution from glp_simplex]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Sergio Barbosa Villas-Boas sbVB <address@hidden>
To: address@hidden, Leonas Sakalauskas <address@hidden>
Subject: help to get dual solution from glp_simplex
Date: Thu, 06 Oct 2011 17:06:09 -0300

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Hi, gurus
 
I'm using glpk with linux, writing in C++.
 
I succeeded in getting results of Simplex by using glp_simplex.
The results are the primal solution.
 
Now I need to get the dual solution (also known as shadow price).
I tried the code below (simplified)
 
////////////////////////////////////////////////////////// begin
 
// load data to lp ....
 
// create param setting method to DUAL
    glp_smcp parm;
    glp_init_smcp(&parm);
    parm.meth = GLP_DUAL;
 
// call simplex
    glp_simplex(lp, &parm);
 
////////////////////////////////////////////////////////// end
 
The glp_simplex function returns the same solution as it the method was
GLP_PRIMAL.
 
I would appreciate if someone could give me an example of how to write code
to get the dual solution (shadow price).
 
Thanks in advance.
 
- ----------------------------------------------------
 +------+  Sergio Barbosa Villas-Boas
/------/|  address@hidden
| sbVB |/  http://www.sbVB.com.br
+------+   Skype: sbvbsbvb
 
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