Attributes
To query and modify properties of a COPT model is through the attribute interface. A variety of different attributes are available, and they can be associated with solutions, or the model.
Problem related
Problem related attributes provide the relevant information of the model composition and description. The names and descriptions of these attributes are summarized below.
Name 
Type 
Description 

Integer 
Number of variables (columns) in the problem 

Integer 
Number of PSD variables in the problem 

Integer 
Number of constraints (rows) in the problem 

Integer 
Number of nonzero elements in the coefficient matrix 

Integer 
Number of nonzero quadratic elements in the quadratic objective function 

Integer 
Number of PSD terms in objective function 

Integer 
Number of symmetric matrices in the problem 

Integer 
Number of binary variables 

Integer 
Number of integer variables 

Integer 
Number of SOS constraints 

Integer 
Number of SecondOrderCone constraints 

Integer 
Number of quadratic constraints 

Integer 
Number of PSD constraints 

Integer 
Number of LMI constraints 

Integer 
Number of indicator constraints 

Integer 
The optimization direction 

Double 
The constant part of the objective function 

Integer 
Whether the problem has quadratic objective function 

Integer 
Whether the problem has PSD terms in objective function 

Integer 
Whether the problem is a MIP 
Cols
Integer attribute.
Number of variables (columns) in the problem.
PSDCols
Integer attribute.
Number of PSD variables in the problem.
Rows
Integer attribute.
Number of constraints (rows) in the problem.
Elems
Integer attribute.
Number of nonzero elements in the coefficient matrix.
QElems
Integer attribute.
Number of nonzero quadratic elements in the quadratic objective function.
PSDElems
Integer attribute.
Number of PSD terms in objective function.
SymMats
Integer attribute.
Number of symmetric matrices in the problem.
Bins
Integer attribute.
Number of binary variables.
Ints
Integer attribute.
Number of integer variables.
Soss
Integer attribute.
Number of SOS constraints.
Cones
Integer attribute.
Number of SecondOrderCone constraints.
QConstrs
Integer attribute.
Number of quadratic constraints.
PSDConstrs
Integer attribute.
Number of PSD constraints.
LMIConstrs
Integer attribute.
Number of LMI (Linear Matrix Inequalities) constraints.
Indicators
Integer attribute.
Number of indicator constraints.
ObjSense
Integer attribute.
The optimization direction.
ObjConst
Double attribute.
The constant part of the objective function.
HasQObj
Integer attribute.
Whether the problem has quadratic objective function.
HasPSDObj
Integer attribute.
Whether the problem has PSD terms in objective function.
IsMIP
Integer attribute.
Whether the problem is a MIP.
Solution related
Solution related attributes provide the relevant information of the solution composition and description. The names and descriptions of these attributes are summarized below.
Name 
Type 
Description 

Integer 
The LP status 

Integer 
The MIP status 

Integer 
Number of simplex iterations performed 

Integer 
Number of barrier iterations performed 

Integer 
Number of explored nodes 

Integer 
Number of solutions in solution pool 

Integer 
Number of parameter tuning results 

Integer 
Whether LP solution is available 

Integer 
Whether LP basis is available 

Integer 
Whether the dual Farkas of an infeasible LP problem is available 

Integer 
Whether the primal ray of an unbounded LP problem is available 

Integer 
Whether MIP solution is available 

Integer 
Number of bounds of columns in IIS 

Integer 
Number of rows in IIS 

Integer 
Number of SOS constraints in IIS 

Integer 
Number of indicator constraints in IIS 

Double 
Whether IIS is available 

Integer 
Whether feasibility LPrelaxation solution is available 

Integer 
Whether the computed IIS is minimal 

Integer 
The LP objective value 

Double 
Best integer objective value for MIP 

Double 
Best bound for MIP 

Double 
Best relative gap for MIP 

Double 
Feasibility relaxation objective value 

Double 
The time spent for the optimization (in seconds) 
LpStatus
Integer attribute.
The LP status. Please refer to General Constants: Solution Status for possible values.
MipStatus
Integer attribute.
The MIP status. Please refer to General Constants: Solution Status for possible values.
SimplexIter
Integer attribute.
Number of simplex iterations performed.
BarrierIter
Integer attribute.
Number of barrier iterations performed.
NodeCnt
Integer attribute.
Number of explored nodes.
PoolSols
Integer attribute.
Number of solutions in solution pool.
TuneResults
Integer attribute.
Number of parameter tuning results
HasLpSol
Integer attribute.
Whether LP solution is available.
HasBasis
Integer attribute.
Whether LP basis is available.
HasDualFarkas
Integer attribute.
Whether the dual Farkas of an infeasible LP problem is available.
HasPrimalRay
Integer attribute.
Whether the primal ray of an unbounded LP problem is available.
HasMipSol
Integer attribute.
Whether MIP solution is available.
IISCols
Integer attribute.
Number of bounds of columns in IIS.
IISRows
Integer attribute.
Number of rows in IIS.
IISSOSs
Integer attribute.
Number of SOS constraints in IIS.
IISIndicators
Integer attribute.
Number of indicator constraints in IIS.
HasIIS
Integer attribute.
Whether IIS is available.
HasFeasRelaxSol
Integer attribute.
Whether feasibility LPrelaxation solution is available.
IsMinIIS
Integer attribute.
Whether the computed IIS is minimal.
LpObjval
Double attribute.
The LP objective value.
BestObj
Double attribute.
Best integer objective value for MIP.
BestBnd
Double attribute.
Best bound for MIP.
BestGap
Double attribute.
Best relative gap for MIP.
FeasRelaxObj
Double attribute.
Feasibility relaxation objective value.
SolvingTime
Double attribute.
The time spent for the optimization (in seconds).
Methods for accessing attributes
In different programming interfaces, the ways to access attributes are slightly different. For details, please refer to the corresponding chapters of each programming language API reference manual:
C++ API: C++ API Reference: Attributes
C# API: C# API Reference: Attributes
Java API: Java API Reference: Attributes
Python API: Python API Reference: Attributes