<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""></div><div class=""> <br class=""><div><blockquote type="cite" class=""><div class="">Am 10.02.2015 um 11:33 schrieb John Forrest <<a href="mailto:john.forrest@fastercoin.com" class="">john.forrest@fastercoin.com</a>>:</div><br class="Apple-interchange-newline"><div class="">
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<div class="moz-cite-prefix">Mike,<br class="">
<br class="">
The problem is due to the elements of 1.0e9 in model. In
postprocessing this led to values of 1.0e-9 which is just on a
particular tolerance.<br class="">
<br class="">
Without preprocessing my tests gave correct solution.<br class="">
<br class="">
It was a bug - I have made postprocessing more robust in 2.9.<br class="">
<br class="">
John Forrest<br class="">
<br class="">
On 09/02/15 11:39, Mike Steglich wrote:<br class="">
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Hello,
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<div class="">I've got an interesting behaviour with the attached
mps file. When I run this problem with the CBC binary (2.8.9 on
OS X and 2.9.0 on Win8.1) then I got the following information:</div>
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<div class="">...</div>
<div class=""><i class="">Coin0505I Presolved problem not optimal,
resolve after postsolve<br class="">
Cgl0013I Postprocessed model is infeasible - possible
tolerance issue - try without preprocessing<br class="">
16 relaxed row infeasibilities - summing to 193<br class="">
16 relaxed row infeasibilities - summing to 193<br class="">
16 relaxed row infeasibilities - summing to 193<br class="">
<br class="">
Result - Optimal solution found<br class="">
<br class="">
Objective value: 813.00000000</i></div>
<div class="">...</div>
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<div class="">The solution file (It doesn't matter whether I use
the solu or gsolu option) shows an different objective function
value of 1925 and values for the variables that are obviously
infeasible. When I set the preprocessing off then the problem
is stated as infeasible.</div>
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<div class="">It could be possible that the problem formulation
and therefore the mps file is stupid. But when I use the same
mps file with glpk, scip and Cplex then I'm able to find in any
case an optimal solution with the objective function value 813
(that is also shown by Cbc).</div>
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<div class="">Thanks,</div>
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<div class="">Mike</div>
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