[SCIP] ERROR: cannot change bounds of multi-aggregated variable

[Gregor Hendel]

Dear Zahra,

I agree with Benny. I assume that you are not creating XOR constraints 
yourself. They are instead created from linear constraints with a 
special parity structure, which is called upgrading in SCIP. As a 
workaround for continuing with your code, you can disable the mentioned 
upgrade by setting the parameter

# enable linear upgrading for constraint handler <xor>
# [type: bool, advanced: FALSE, range: {TRUE,FALSE}, default: TRUE]
constraints/linear/upgrade/xor = TRUE

to FALSE.

Best,
Gregor


Am 20.02.19 um 08:55 schrieb Benjamin Müller:
> Dear Zahra,
>
> looks like a bug in SCIP. Could you write out the MILP in the cip 
> format and send it to me, please? Thanks!
>
> Best,
> Benjamin
>
> On 2/18/19 9:36 AM, Zahra Eskandari wrote:
>> Hi everyone,
>>
>> I have a MILP problem which i try to solve with SCIP. when it solved 
>> by "count", it generate all feasible solution without any error. But 
>> when I use "Optimize" to solve it, it generate these errors:
>>
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/tree.c:1824] 
>> ERROR: cannot change bounds of multi-aggregated variable <agg_t_t_z(64)>
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/tree.c:2041] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/scip_var.c:5597] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/cons_xor.c:3251] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/cons_xor.c:5037] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/cons.c:4083] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/scip_solve.c:1050] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/scip_solve.c:1420] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/scip_solve.c:2448] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/scip_solve.c:2660] 
>> ERROR: Error <-9> in function call
>> [/nfs/OPTI/jenkins/workspace/SCIPOptSuite_linux_release/scipoptsuite-6.0.0/scip/src/scip/heur_rins.c:391] 
>> ERROR: Error <-9> in function call
>> WARNING: Transformed variable <agg_t_t_z(50)> not released when 
>> freeing SCIP. Consider releasing variable first.
>> Segmentation fault (core dumped)
>>
>>
>>
>>
>> it is notable that I use PySCIPOpt.
>>
>> if someone has some opinions, please, let me know.
>>
>> Zahra
>>
>>
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>>
>

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