[Help-glpk] [Fwd: Can we set a row with equal upper and lower bound?]

[Andrew Makhorin]

-------- Forwarded Message --------
From: Wenfei Wu <address@hidden>
To: address@hidden
Subject: Can we set a row with equal upper and lower bound?
Date: Fri, 29 Jul 2011 12:07:35 -0700

Hi, all
   I am using GLPK now. the version is 4.45. I use it in Cygwin
   I have a problem.
   I set up a row with upper bound 0 and lower bound 0, the when I run
it. Problem appears.

 Code is
   glp_set_row_bnds(lp, 1, GLP_DB, 0.0, 0.0);

 output is
  glp_simplex: row 1: lb = 0, ub = 0; incorrect bounds

 Then I change the code
   glp_set_row_bnds(lp, 1, GLP_DB, 0.0, 0.001);
and it works.

 Does this mean that we cannot set both bound equal?  But in the GLPK
reference Manual, on page 13, it says "Bounds of variables can be
nite as well as innite. Besides, lower and upper bounds can be equal
to each other."

  Thanks.
  Wenfei