List of attributes

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Here a brief list of the available attributes is presented.  The attributes are extensively covered in the Model Attributes chapter.  An * below indicates this attribute is also controlled by a GAMS option command.

 

Attribute

Main Usage relative to Solve

Notes

Pre

Post

Bratio*

X

 

Controls whether to discard advanced basis

Cheat

X

 

Minimum improvement in MIP objective value

Cutoff

X

 

Limit on acceptable MIP objective value

Domlim

X

 

Number of numerical errors allowed during solution

Domusd

 

X

Number of equation evaluation numerical errors encountered in solving

Holdfixed

X

 

Reduces problem size by eliminating fixed variables

Iterlim*

X

 

Iteration limit which as of 23.1 has a default value of 2 billion

Iterusd

 

X

Number of iterations to solve problem

Limcol*

X

 

Limit on number of variables in output

Limrow*

X

 

Limit on number of equations in output

Modelstat

 

X

Model solution status. Values of 1 or 2 or 8 generally denotes optimal solution or with CNS values of 15 and 16., Other values denote infeasible, unbounded, solver failure etc.  Consult solver manuals or the modelstat table for more.

Nodlim

X

 

Node limit in MIP

Numdepnd        

 

X

Number of dependencies in a CNS model

Numdvar

 

X

Number of discrete variables in the model

Numequ

 

X

Number of total equations in the model

Numinfes

 

X

Number of infeasibilities in the solution

Numnopt

 

X

Number of non-optimalities in the solution

Numnz

 

X

Number of non-zero entries in the model coefficient matrix

Numunbd

 

X

Number of unbounded variables in the solution

Numvar

 

X

Number of single variables in the model

Optca*

X

 

Max absolute MIP optimality gap

Optcr*

X

 

Max relative MIP optimality gap

Optfile

X

 

Causes use of solver options file

Prioropt

X

 

Causes use of MIP priorities

Reslim*

X

 

Max time available to solve in seconds

Resusd

 

X

Time in CPU seconds the solver used to solve the model

Robj

 

X

Relaxed objective value from MIPs when solve doesn't work

Scaleopt

X

 

Use user defined internal scaling factors

Solprint*

X

 

Controls solution print in LST file. A related set of solprint constants is also present.

Solveopt

X

 

Merge or replace solution information

Solvestat

 

X

Solver termination status. Value of 1 denotes normal termination, larger values denote iteration limits, solver failure etc. A full list appears here.

Sysout*

X

 

Expands solution output

Tmodstat

 

X

Can be used in put statements to give problem optimality status text

Tolinfrep

X

 

Sets tolerance for infeasible solutions.  The default value is 1.0e-6

Tolproj

X

 

Sets tolerance for filtering primal and dual variables when reading solution files default is 1e-6

Tryint

X

 

Try to make current solution integer and use it in MIP solve

TryLinear

X

 

Examine empirical NLP model to see if there are any NLP terms active.  If there are none the default LP solver will be used. To activate use modelname.trylinear=1.  Default value is zero.  The procedure also checks to see if QCP, and DNLP models can be reduced to an LP; MIQCP and MINLP can be solved as an MIP; RMIQCP and RMINLP can be solved as an RMIP.

Tsolstat

 

X

Can be used in put statements to give problem optimality status text

Workspace*

X

 

Amount of CPU memory to allocate