[SCIP] SCIP presolver for MIQCP

[Ahmed Ibrahim]

Hi All,
I was wondering whether it is normal for the presolver to return a presolved MIQCP with a larger number of continuous variables and larger number of linear constraints than was provided in the original instance?
The details are provided below (N.B iam using opti toolbox which interfaces SCIP with Matlab):
 Problem Properties:
# Decision Variables:      527
# Constraints:             4261
  # Linear Inequality:     256
  # Quadratic Constraints: 2844
  # Bounds:                1054
  # Binary Variables:      107
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  Solver Parameters:
Solver:                    SCIP
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numerics/lpfeastol = 1e-012
feasible solution found by trivial heuristic after 0.0 seconds, objective value -1.000000e+000
presolving:
(round 1, fast)       9 del vars, 20 del conss, 0 add conss, 0 chg bounds, 0 chg sides, 0 chg coeffs, 0 upgd conss, 0 impls, 42 clqs
(round 2, fast)       9 del vars, 20 del conss, 7560 add conss, 0 chg bounds, 0 chg sides, 0 chg coeffs, 840 upgd conss, 0 impls, 42 clqs
(round 3, fast)       9 del vars, 20 del conss, 7560 add conss, 0 chg bounds, 840 chg sides, 840 chg coeffs, 840 upgd conss, 2520 impls, 760 clqs
(round 4, exhaustive) 9 del vars, 20 del conss, 7560 add conss, 0 chg bounds, 840 chg sides, 840 chg coeffs, 1074 upgd conss, 2520 impls, 760 clqs
(round 5, medium)     9 del vars, 22 del conss, 7644 add conss, 0 chg bounds, 840 chg sides, 840 chg coeffs, 1074 upgd conss, 2604 impls, 844 clqs
(round 6, exhaustive) 9 del vars, 108 del conss, 7646 add conss, 0 chg bounds, 840 chg sides, 840 chg coeffs, 1074 upgd conss, 2604 impls, 844 clqs
(round 7, exhaustive) 9 del vars, 108 del conss, 7646 add conss, 0 chg bounds, 840 chg sides, 1917 chg coeffs, 1074 upgd conss, 2604 impls, 844 clqs
   (0.2s) probing: 51/106 (48.1) - 0 fixings, 0 aggregations, 0 implications, 0 bound changes
   (0.2s) probing aborted: 50/50 successive totally useless probings
presolving (8 rounds: 8 fast, 5 medium, 4 exhaustive):
 9 deleted vars, 108 deleted constraints, 7646 added constraints, 0 tightened bounds, 0 added holes, 840 changed sides, 1917 changed coefficients
 2604 implications, 867 cliques
presolved problem has 3038 variables (106 bin, 0 int, 0 impl, 2932 cont) and 10638 constraints
   2604 constraints of type <varbound>
     42 constraints of type <setppc>
      2 constraints of type <and>
   5882 constraints of type <linear>
    104 constraints of type <logicor>
   2004 constraints of type <quadratic>


Regards,
Ahmed
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