[SCIP] Different Problems while using SCIP with YALMIP

[Valerie Schrayvogel]

Hello,

 

I have a couple of questions regarding using SCIP (nonlinear) under YALMIP
(interfaced for Matlab through the OPTI Toolbox).

 

(1) I get the message "Original variable <nlobj> not released when freeing
SCIP. Consider releasing variable first.": I could not find out how this
works under YALMIP.

As far as I understood, this is not necessary but quite useful to use the
Memory-Management. Is there a way to handle this using YALMIP?

 

(2) Furthermore I am a litte irritated by the following message:

 

SCIP Status        : problem is solved [optimal solution found]

Solving Time (sec) : 0.22

Solving Nodes      : 1

Primal Bound       : +4.79653886000805e+03 (1 solutions)

Dual Bound         : +4.79653886000805e+03

Gap                : 0.00

  [linear] <lincon45>: <xvar33>[C] -<xvar37>[C] <= 1e-05;

violation: right hand side is violated by 1.50505108851939e-05

best solution is not feasible in original problem

 

Does it mean that the solution is not feasable (yalmip reports the problem
0, which means feasable solution found)?

 

(3) I calculate the same type of NLP (accurate: a heat exchanger network) a
couple of times with different parameters (Temperatures at the in- an
outlet). In most cases yalmip reports the problem "0" but in some cases it
returns 9 (which is defined as "Unknown problem in solver" in YALMIP).

Do you have any idea what could be the problem here?

 

Thank you in advance!

 

Best, 

 

Valerie 

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