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<div class="moz-cite-prefix">Dear Kai Wei,<br>
<br>
as far as I can see from your output file, the only plugins
changing the bounds of variables are the storeGraph constraint
handler and possibly the branching rule (when creating children,
but probably, branching is enforced by the storeGraph constraint
handler). This looks ok.<br>
<br>
Whenever there are variables with negative reduced cost, could it
be that the storeGraph constraint handler fixed them to 0 already?
In that case, your pricing should not generate them again if you
correctly modify your pricing problem based on your branching
decisions.<br>
<br>
If this is not the case, can you check that SCIPvarGetCol() is not
NULL for the variables with reduced cost and whether
SCIPcolIsInLP(SCIPvarGetCol()) holds?<br>
<br>
Best,<br>
Gerald<br>
<br>
On 15.03.2016 06:45, <a class="moz-txt-link-abbreviated" href="mailto:weikaimas@163.com">weikaimas@163.com</a> wrote:<br>
</div>
<blockquote cite="mid:2016031513450732265811@163.com" type="cite">
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<div><span></span>Hi Gerald,</div>
<div><br>
</div>
<div>I attached the statistics in the attachment. </div>
<div><br>
</div>
<div><span style="font-size: 10.5pt; line-height: 1.5;
background-color: window;">Waiting for your reply. </span></div>
<div><br>
</div>
<div>Best regards,</div>
<div><br>
</div>
<div>Kai WEI</div>
<div><br>
</div>
<blockquote style="margin-top: 0px; margin-bottom: 0px;
margin-left: 0.5em;">
<div> </div>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<div style="PADDING-RIGHT: 8px; PADDING-LEFT: 8px; FONT-SIZE:
12px;FONT-FAMILY:tahoma;COLOR:#000000; BACKGROUND: #efefef;
PADDING-BOTTOM: 8px; PADDING-TOP: 8px">
<div><b>From:</b> <a moz-do-not-send="true"
href="mailto:gamrath@zib.de">Gerald Gamrath</a></div>
<div><b>Date:</b> 2016-03-15 00:30</div>
<div><b>To:</b> <a moz-do-not-send="true"
href="mailto:weikaimas@163.com">weikaimas@163.com</a></div>
<div><b>CC:</b> <a moz-do-not-send="true"
href="mailto:scip@zib.de">scip</a></div>
<div><b>Subject:</b> Re: Reduced cost about variables in LP
relaxation</div>
</div>
</div>
<div>
<div class="FoxDiv20160315133338930940">
<div class="moz-cite-prefix">Hi Wei Kai,<br>
<br>
could you please print the statistics at the end of the
solving process and send them to me. Probably, you can see
there which propagator did reductions.<br>
<br>
Best,<br>
Gerald<br>
<br>
<br>
On 12.03.2016 06:49, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:weikaimas@163.com">weikaimas@163.com</a>
wrote:<br>
</div>
<blockquote cite="mid:2016031213494287355325@163.com"
type="cite" style="margin-top: 0px; margin-bottom: 0px;
margin-left: 0.5em;">
<div><span></span>Dear Gerald,</div>
<div><br>
</div>
<div>I have tried to use <span style="font-size: 10.5pt;
line-height: 1.5; background-color: window;">SCIPchgVarUbLazy()
to set an upper bound value for each variable in 3.2.0
and use version 3.2.1. </span></div>
<div><span style="font-size: 10.5pt; line-height: 1.5;
background-color: window;">However, I also found some
variables with negative reduced cost in both above
methods. The number of negative </span><span
style="font-size: 10.5pt; line-height: 1.5;
background-color: window;"> </span><span
style="font-size: 10.5pt; line-height: 1.5;
background-color: window;">reduced cost variable </span></div>
<div><span style="font-size: 10.5pt; line-height: 1.5;
background-color: window;">is much less than version
3.2.0 without </span><span style="font-size: 10.5pt;
line-height: 1.5; background-color: window;">SCIPchgVarUbLazy(),
and both new methods have the some results.</span></div>
<div><span style="font-size: 10.5pt; line-height: 1.5;
background-color: window;"><br>
</span></div>
<div>Would have some methods to avoid the this phenomenon
because the pricing method will find some useless
variables.</div>
<div><span style="font-family: 'Microsoft YaHei UI',
Tahoma; font-size: 10.5pt; line-height: 1.5;
background-color: window;"><br>
</span></div>
<div><span style="font-family: 'Microsoft YaHei UI',
Tahoma; font-size: 10.5pt; line-height: 1.5;
background-color: window;">Best regards,</span></div>
<div><span style="font-family: 'Microsoft YaHei UI',
Tahoma; font-size: 10.5pt; line-height: 1.5;
background-color: window;">Kai Wei</span></div>
<div><span style="font-size: 10.5pt; line-height: 1.5;
background-color: window;"><br>
</span></div>
<div><span style="font-size: 10.5pt; line-height: 1.5;
background-color: window;"><br>
</span></div>
<div><br>
</div>
<div><br>
</div>
<blockquote style="margin-top: 0px; margin-bottom: 0px;
margin-left: 0.5em;">
<div> </div>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0cm 0cm 0cm">
<div style="PADDING-RIGHT: 8px; PADDING-LEFT: 8px;
FONT-SIZE: 12px;FONT-FAMILY:tahoma;COLOR:#000000;
BACKGROUND: #efefef; PADDING-BOTTOM: 8px;
PADDING-TOP: 8px">
<div><b>From:</b> <a moz-do-not-send="true"
href="mailto:gamrath@zib.de">Gerald Gamrath</a></div>
<div><b>Date:</b> 2016-03-04 18:23</div>
<div><b>To:</b> <a moz-do-not-send="true"
href="mailto:weikaimas@163.com">weikaimas@163.com</a>;
<a moz-do-not-send="true"
href="mailto:scip@zib.de">scip</a></div>
<div><b>Subject:</b> Re: Reduced cost about
variables in LP relaxation</div>
</div>
</div>
<div>
<div class="FoxDiv20160312131757072986">
<div class="moz-cite-prefix">Dear Wei Kai,<br>
<br>
if a variable has an upper bound and is nonbasic
at its upper bound in the LP solution, it may have
negative reduced cost.<br>
<br>
Did you set an upper bound for your variables? If
so, you can use SCIPchgVarUbLazy() to set an upper
bound value which is implicitly given by the
constraints and should not explicitly added to the
LP as bound of the variable.<br>
<br>
However, we also noticed that some propagators
installed upper bound on variables in
branch-and-price applications. Although the
reductions were correct, they may lead to troubles
as you are now observing them. Therefore, these
propagators are now automatically disabled if
pricers are active. This fix is already included
in the bugfix version 3.2.1 released earlier this
week. Please try if updating your version fixes
your issues.<br>
<br>
Best,<br>
Gerald<br>
<br>
On 04.03.2016 08:56, <a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:weikaimas@163.com">weikaimas@163.com</a>
wrote:<br>
</div>
<blockquote
cite="mid:2016030415555871994824@163.com"
type="cite" style="margin-top: 0px; margin-bottom:
0px; margin-left: 0.5em;"> Hi all,
<div><br>
</div>
<div> I have used SCIP to implement a B&P
procedure. At leaf nodes, before I implement
pricing algorithm I use SCIPgetVarRedcosr()</div>
<div>to check the reduced cost of all variables (<span
style="font-size: 10.5pt; line-height: 1.5;
background-color: window;">SCIPgetLPSolstat()
returns 1</span><span style="font-size:
10.5pt; line-height: 1.5; background-color:
window;">). I found some variables with
negative reduced cost.</span></div>
<div><span style="font-size: 10.5pt; line-height:
1.5; background-color: window;"> Can you give
me the reasons about </span><span
style="font-size: 10.5pt; line-height: 1.5;
background-color: window;">this phenomenon?
How can I avoid to find the variables with
negative reduced cost in my pricing algorithm?</span></div>
<div><br>
</div>
<div><span style="font-family: 'Microsoft YaHei
UI', Tahoma; line-height: normal;">Best
regards,</span></div>
<div><span style="font-family: 'Microsoft YaHei
UI', Tahoma; line-height: normal;"><br>
</span></div>
<div><span style="font-family: 'Microsoft YaHei
UI', Tahoma; line-height: normal;">Kai WEI</span></div>
<div><br>
</div>
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