[SCIP] A question about initial solution of branch and price.

[Matthias Miltenberger]

Dear Kai Wei,

when I run your model SCIP shows an optimal objective value of 0.
Please check again that your code actually does what you want. You may 
try compiling in debug mode ("make OPT=dbg") and enabling more debug 
output ("#define SCIP_DEBUG" at the top of source files) to find out 
what's going on.

all the best
Matthias

On 03.11.2015 09:16, weikaimas at 163.com wrote:
> Hi Matthias,
>
> Thanks for your reply.
>
> I did not attach all my model in the last email. I attach this model 
> in this email.
>
> The model is printed by 
>   SCIP_CALL( SCIPwriteLP(scip, "N_initial_model.lp") ), in my code.
>
> SCIP shows the objective value is 30 (see the picture I attached in my 
> last email).
>
> I checked all my code without finding any mistake.
>
> Would like to give me some suggeations.
>
> Best regard,
>
> Kai Wei.
>
>     *From:* Matthias Miltenberger <mailto:miltenberger at zib.de>
>     *Date:* 2015-11-03 15:55
>     *To:* weikaimas at 163.com <mailto:weikaimas at 163.com>
>     *CC:* scip <mailto:scip at zib.de>
>     *Subject:* Re: [SCIP] A question about initial solution of branch
>     and price.
>     Hey Kai Wei,
>
>     I do not see how the model you described corresponds to the SCIP
>     output you sent us. Where are the 337 constraints coming from?
>     I suppose there's something wrong in your own code.
>
>     all the best
>     Matthias
>
>     On 03.11.2015 08:20, weikaimas at 163.com wrote:
>>
>>>     Hi,
>>>      I have a branch and price algorithm. I am facing a problem when
>>>     I set the initial solution.
>>>
>>>     When I set the parameter to zero for each variable in objective
>>>     function, SCIP shows the primal bound is 30.
>>>
>>>     In my problem, the primal bound given by SCIP also 30 unit
>>>     bigger than the real primal bound.
>>>
>>>     I don't know why this happens.
>>>     I attach the initial model and SCIP result in the following.
>>>
>>>     \ENCODING=ISO-8859-1
>>>     \Problem name: mymodel
>>>
>>>     Minimize
>>>      obj:
>>>     Subject To
>>>      Constraint0:   x_1_1  = 30
>>>      Constraint1:   x_2_1  = 10
>>>      Constraint2:   x_3_1  = 30
>>>      Constraint3:   x_4_1  = 19
>>>      Constraint4:   x_5_1  = 17
>>>      Constraint5:   x_6_1  = 22
>>>      Constraint6:   x_7_1  = 28
>>>      Constraint7:   x_8_1  = 21
>>>      Constraint8:   x_9_1  = 27
>>>      Constraint9:   x_10_1  = 20
>>>      Constraint10:  x_11_1  = 10
>>>      Constraint11:  x_12_1  = 21
>>>      Constraint12:  x_13_1  = 14
>>>      Constraint13:  x_14_1  = 11
>>>      Constraint14:  x_15_1  = 28
>>>      Constraint15:  x_16_1  = 21
>>>      Constraint16:  x_17_1  = 21
>>>      Constraint17:  x_18_1  = 20
>>>      Constraint18:  x_19_1  = 16
>>>      Constraint19:  x_20_1  = 24
>>>      Constraint20:  - RgConstraint20  = 0
>>>      Constraint21:  - RgConstraint21  = 0
>>>      Constraint22:  - RgConstraint22  = 0
>>>      Constraint23:  - RgConstraint23  = 0
>>>      Constraint24:  - RgConstraint24  = 0
>>>      Constraint25:  - RgConstraint25  = 0
>>>      Constraint26:  - RgConstraint26  = 0
>>>      Constraint27:  - RgConstraint27  = 0
>>>      Constraint28:  - RgConstraint28  = 0
>>>
>>>
>>>     best regard,
>>>
>>>     Kai Wei
>>
>>
>>
>>     _______________________________________________
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>>     Scip at zib.de
>>     http://listserv.zib.de/mailman/listinfo/scip
>
>     -- 
>     \__________________
>     Matthias Miltenberger
>     Zuse Institute Berlin
>     Takustr. 7, 14195 Berlin
>     www.zib.de/miltenberger
>     miltenberger at zib.de
>     +49 (30) 841 85-245
>
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>
>

-- 
\__________________

Matthias Miltenberger
Zuse Institute Berlin
Takustr. 7, 14195 Berlin
www.zib.de/miltenberger
miltenberger at zib.de
+49 (30) 841 85-245

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