[Scip] Error (-6)

[Tobias Achterberg]

Hi Oscar,

it seems that your the root LP relaxation is unbounded. Unfortunately, The SoPlex
interface does not provide a primal ray that is needed in this case to look for cutting
planes that cut off this ray.

Btw: This problem is an LP anyway. Using a MIP solver like SCIP to solve it is somekind of
overkill. You can directly solve it with SoPlex (or any other LP solver). I guess that the
LP solver will tell you that the problem is unbounded.


Best, Tobias


Oscar Gustafsson wrote:
> Dear all,
> 
> I have installed SCIP 1.00 with SOPLEX 1.3 and get the following error 
> when running a test problem (I have others working fine though).
> 
> Any ideas?
> 
> Regards
> 
> Oscar Gustafsson
> 
> ---
> 
> SCIP version 1.00 [precision: 8 byte] [memory: block] [mode: optimized] 
> [LP solver: SOPLEX 1.3.0]
> Copyright (c) 2002-2007 Konrad-Zuse-Zentrum fuer Informationstechnik 
> Berlin (ZIB)
> 
> user parameter file <scip.set> not found - using default parameters
> 
> SCIP> read test1.lp
> original problem has 513 variables (0 bin, 0 int, 0 impl, 513 cont) and 
> 32768 constraints
> SCIP> optimize
> 
> presolving:
> (round 1) 0 del vars, 15568 del conss, 0 chg bounds, 15568 chg sides, 0 
> chg coeffs, 0 upgd conss, 0 impls, 0 clqs
> presolving (2 rounds):
>   0 deleted vars, 15568 deleted constraints, 0 tightened bounds, 0 added 
> holes, 15568 changed sides, 0 changed coefficients
>   0 implications, 0 cliques
> presolved problem has 513 variables (0 bin, 0 int, 0 impl, 513 cont) and 
> 17200 constraints
>    17200 constraints of type <linear>
> Presolving Time: 134.18
> 
> [src/scip/lpi_spx.cpp:2029] ERROR: SCIPlpiGetPrimalRay() not supported by 
> SOPLEX
> [src/scip/lp.c:11096] ERROR: Error <-6> in function call
> [src/scip/lp.c:10086] ERROR: Error <-6> in function call
> [src/scip/solve.c:672] ERROR: Error <-6> in function call
> [src/scip/solve.c:1765] ERROR: Error <-6> in function call
> [src/scip/solve.c:2394] ERROR: Error <-6> in function call
> [src/scip/solve.c:2950] ERROR: Error <-6> in function call
> [src/scip/scip.c:4858] ERROR: Error <-6> in function call
> [src/scip/dialog_default.c:826] ERROR: Error <-6> in function call
> [src/scip/dialog.c:777] ERROR: Error <-6> in function call
> [src/scip/dialog.c:323] ERROR: Error <-6> in function call
> [src/scip/scip.c:2376] ERROR: Error <-6> in function call
> [src/scip/scipshell.c:347] ERROR: Error <-6> in function call
> [src/scip/scipshell.c:405] ERROR: Error <-6> in function call
> SCIP Error (-6): error in LP solver
> 
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