[SCIP] set/vbc/dispsols
Gotzes, Uwe Dr.
Uwe.Gotzes at open-grid-europe.com
Fri Dec 16 15:07:46 CET 2016
Ok, I see, thanks!
Could you also say something about
> Regarding your answer to my "frac"-question: If there are 0 fractional variables in the LP-solution of node 2, why isn't there a primal bound resulting from it?
> time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons |cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
> 0.0s| 2 | 1 | 3 | 0.0 | 169k| 1 | - | 2 | 3 | 2 | 2 | 3 | 0 | 0 |8.000000e+000 | -- | Inf
-----Ursprüngliche Nachricht-----
Von: Jakob Witzig [mailto:witzig at zib.de]
Gesendet: Freitag, 16. Dezember 2016 14:58
An: Gotzes, Uwe Dr.
Cc: scip at zib.de
Betreff: Re: [SCIP] set/vbc/dispsols
Hi Uwe!
No, because the SCIP output only says that the solution with objective value 4 was found at the 5th node that was evaluated, this need not to be the node number with 5.
Cheers,
Jakob
Am 16.12.2016 um 13:28 schrieb Gotzes, Uwe Dr.:
> Hi Jakob,
>
> my problem is that the solution with objective value -4 corresponds to node 5 and the solution with objective value -7 corresponds to node 6. In the vbc-file it is somehow the other way round: "U -4" is printed "close" to the new (P)ainting of node 6 while "U -7" occurs close to the new painting of node 5 in the file.
>
>>> 00:00:00.00 P 6 14
>>> 00:00:00.00 U -4.000000
> ...
>>> 00:00:00.00 P 5 14
> ...
>>> 00:00:00.00 U -7.000000
>
> Isn't that strange?
>
> Regarding your answer to my "frac"-question: If there are 0 fractional variables in the LP-solution of node 2, why isn't there a primal bound resulting from it?
> time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons |cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
> 0.0s| 2 | 1 | 3 | 0.0 | 169k| 1 | - | 2 | 3 | 2 | 2 | 3 | 0 | 0 |8.000000e+000 | -- | Inf
>
> Best,
> Uwe
>
>
> -----Ursprüngliche Nachricht-----
> Von: Jakob Witzig [mailto:witzig at zib.de]
> Gesendet: Freitag, 16. Dezember 2016 13:01
> An: Gotzes, Uwe Dr.
> Cc: scip at zib.de
> Betreff: Re: [SCIP] set/vbc/dispsols
>
> One additional remark or workaround. You can look at the lines of type:
>
> 00:00:00.00 U -7.000000
>
> This is new upper bound, i.e., the objective values of the new incumbent. In your case you need to multiply with -1 because your problem seems to be a maximization problem and SCIP's transformed problem is always a minimization problem.
>
> Cheers
> Jakob
>
> Am 16.12.2016 um 12:56 schrieb Jakob Witzig:
>> Hi Uwe,
>>
>> I had a look into the code and it seems that the vbc-format does not
>> support information about the new incumbent solution. If you use bak
>> instead of vbc, SCIP will print a line like:
>>
>> integer {nodenumber} {parentnumber} {boundtype} {newobj}
>>
>> The "frac" column shows the number of fractional variables in the LP
>> solution. If all integer variables have an integral solution value in
>> the LP solution a "-" is printed.
>>
>> Cheers,
>> Jakob
>>
>> Am 16.12.2016 um 12:02 schrieb Gotzes, Uwe Dr.:
>>> Hi,
>>>
>>> I have a very simple problem and tried to tell scip to apply plain
>>> lp-based branch and bound to it.
>>>
>>> I have set vbc/dispsols = TRUE to visualize the nodes where
>>> solutions are found.
>>>
>>> This option results in the two lines 00:00:00.00 P 6 14 and
>>> 00:00:00.00 P 5 14 in the vbc-file. (P int int Number of the node,
>>> number of the nodes colour.)
>>>
>>> I have two questions:
>>> 1. Is it possible to figure out the value of the solution found in
>>> the respective node from the vbc-file?
>>> 2. What is the meaning of the minus sign in the "frac"-column of node 2?
>>>
>>>
>>> Scip output is:
>>>
>>> time | node | left |LP iter|LP it/n| mem |mdpt |frac |vars |cons
>>> |cols |rows |cuts |confs|strbr| dualbound | primalbound | gap
>>> 0.0s| 1 | 0 | 0 | - | 166k| 0 | - | 2 | 3
>>> | 2 | 0 | 0 | 0 | 0 | -- | -- | Inf
>>> (node 1) LP relaxation is unbounded (LP 0)
>>> 0.0s| 1 | 0 | 2 | - | 167k| 0 | - | 2 | 3
>>> | 2 | 2 | 2 | 0 | 0 | -- | -- | Inf
>>> (node 1) LP relaxation is unbounded (LP 1)
>>> 0.0s| 1 | 0 | 3 | - | 168k| 0 | 1 | 2 | 3
>>> | 2 | 2 | 3 | 0 | 0 |8.428571e+000 | -- | Inf
>>> 0.0s| 1 | 2 | 3 | - | 168k| 0 | 1 | 2 | 3
>>> | 2 | 2 | 3 | 0 | 0 |8.428571e+000 | -- | Inf
>>> 0.0s| 2 | 1 | 3 | 0.0 | 169k| 1 | - | 2 | 3
>>> | 2 | 2 | 3 | 0 | 0 |8.000000e+000 | -- | Inf
>>> 0.0s| 3 | 2 | 5 | 1.0 | 169k| 1 | 1 | 2 | 3
>>> | 2 | 2 | 3 | 0 | 0 |7.500000e+000 | -- | Inf
>>> 0.0s| 4 | 3 | 6 | 1.0 | 170k| 2 | 1 | 2 | 3
>>> | 2 | 2 | 3 | 0 | 0 |7.000000e+000 | -- | Inf
>>> * 0.0s| 5 | 2 | 7 | 1.0 | 170k| 3 | - | 2 | 3
>>> | 2 | 2 | 3 | 0 | 0 |7.000000e+000 |4.000000e+000 | 75.00%
>>> * 0.0s| 6 | 0 | 8 | 1.0 | 170k| 3 | - | 2 | 3
>>> | 2 | 2 | 3 | 0 | 0 |7.000000e+000 |7.000000e+000 | 0.00%
>>>
>>> The content of the generated vbc-file:
>>>
>>> #TYPE: COMPLETE TREE
>>> #TIME: SET
>>> #BOUNDS: SET
>>> #INFORMATION: STANDARD
>>> #NODE_NUMBER: NONE
>>> 00:00:00.00 N 0 1 3
>>> 00:00:00.00 I 1
>>> \inode:\t1\idepth:\t0\nvar:\t-\nbound:\t-100000000000000000000.00000
>>> 0
>>> 00:00:00.00 P 1 11
>>> 00:00:00.00 N 1 2 3
>>> 00:00:00.00 I 2 \inode:\t2\idepth:\t1\nvar:\t-\nbound:\t-8.428571
>>> 00:00:00.00 I 2 \inode:\t2\idepth:\t1\nvar:\tt_x1 [-0,1e+020] <=
>>> 2.000000\nbound:\t-8.000000
>>> 00:00:00.00 N 1 3 3
>>> 00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\t-\nbound:\t-8.428571
>>> 00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\tt_x1 [-0,1e+020] >=
>>> 3.000000\nbound:\t-8.428571
>>> 00:00:00.00 I 1
>>> \inode:\t1\idepth:\t0\nvar:\t-\nbound:\t-8.428571\nnr:\t1
>>> 00:00:00.00 P 1 2
>>> 00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\tt_x1 [3,1e+020] >=
>>> 3.000000\nbound:\t100000000000000000000.000000\nnr:\t2
>>> 00:00:00.00 P 3 2
>>> 00:00:00.00 I 3 \inode:\t3\idepth:\t1\nvar:\tt_x1 [3,1e+020] >=
>>> 3.000000\nbound:\t100000000000000000000.000000\nnr:\t2
>>> 00:00:00.00 P 3 4
>>> 00:00:00.00 N 2 4 3
>>> 00:00:00.00 I 4 \inode:\t4\idepth:\t2\nvar:\t-\nbound:\t-7.500000
>>> 00:00:00.00 I 4 \inode:\t4\idepth:\t2\nvar:\tt_x2 [-0,3] <=
>>> 0.000000\nbound:\t-7.500000
>>> 00:00:00.00 N 2 5 3
>>> 00:00:00.00 I 5 \inode:\t5\idepth:\t2\nvar:\t-\nbound:\t-7.500000
>>> 00:00:00.00 I 5 \inode:\t5\idepth:\t2\nvar:\tt_x2 [-0,3] >=
>>> 1.000000\nbound:\t-7.000000
>>> 00:00:00.00 I 2 \inode:\t2\idepth:\t1\nvar:\tt_x1 [-0,2] <=
>>> 2.000000\nbound:\t-7.500000\nnr:\t3
>>> 00:00:00.00 P 2 2
>>> 00:00:00.00 N 4 6 3
>>> 00:00:00.00 I 6 \inode:\t6\idepth:\t3\nvar:\t-\nbound:\t-6.000000
>>> 00:00:00.00 I 6 \inode:\t6\idepth:\t3\nvar:\tt_x1 [-0,2] <=
>>> 1.000000\nbound:\t-4.000000
>>> 00:00:00.00 N 4 7 3
>>> 00:00:00.00 I 7 \inode:\t7\idepth:\t3\nvar:\t-\nbound:\t-6.000000
>>> 00:00:00.00 I 7 \inode:\t7\idepth:\t3\nvar:\tt_x1 [-0,2] >=
>>> 2.000000\nbound:\t-6.000000
>>> 00:00:00.00 I 4 \inode:\t4\idepth:\t2\nvar:\tt_x2 [-0,0] <=
>>> 0.000000\nbound:\t-6.000000\nnr:\t4
>>> 00:00:00.00 P 4 2
>>> 00:00:00.00 I 6 \inode:\t6\idepth:\t3\nvar:\tt_x1 [-0,1] <=
>>> 1.000000\nbound:\t-4.000000\nnr:\t5
>>> 00:00:00.00 P 6 2
>>> 00:00:00.00 P 6 14
>>> 00:00:00.00 U -4.000000
>>> 00:00:00.00 I 5 \inode:\t5\idepth:\t2\nvar:\tt_x2 [1,3] >=
>>> 1.000000\nbound:\t-7.000000\nnr:\t6
>>> 00:00:00.00 P 5 2
>>> 00:00:00.00 P 5 14
>>> 00:00:00.00 I 7 \inode:\t7\idepth:\t3\nvar:\tt_x1 [-0,2] >=
>>> 2.000000\nbound:\t-6.000000\nnr:\t6
>>> 00:00:00.00 P 7 4
>>> 00:00:00.00 U -7.000000
>>>
>>> Thanks,
>>> Uwe
>>>
>>> _______________________________________________
>>> Scip mailing list
>>> Scip at zib.de
>>> http://listserv.zib.de/mailman/listinfo/scip
>>>
>>
>>
>
>
> --
> Jakob Witzig
>
> Zuse Institute Berlin (ZIB)
>
> Division Mathematical Optimization and Scientific Information Research
> Group Mathematical Optimization Methods
>
> Takustrasse 7
> 14195 Berlin
>
> Tel. : +49 (0)30 84185-416
> Fax : +49 (0)30 84185-269
> email: witzig at zib.de
>
--
Jakob Witzig
Zuse Institute Berlin (ZIB)
Division Mathematical Optimization and Scientific Information Research Group Mathematical Optimization Methods
Takustrasse 7
14195 Berlin
Tel. : +49 (0)30 84185-416
Fax : +49 (0)30 84185-269
email: witzig at zib.de
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