Model characteristics statistics

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The next item of output is the model size statistics.  For the shortmodel.gms example it is

 

MODEL STATISTICS

 

BLOCKS OF EQUATIONS       2     SINGLE EQUATIONS        3

BLOCKS OF VARIABLES       2     SINGLE VARIABLES        4

NONZERO ELEMENTS          9

 

While for the example simpnlp.gms it is

 

MODEL STATISTICS

 

BLOCKS OF EQUATIONS       1     SINGLE EQUATIONS        1

BLOCKS OF VARIABLES       2     SINGLE VARIABLES        2

NONZERO ELEMENTS          2     NON LINEAR N-Z          2

DERIVATIVE POOL           6     CONSTANT POOL          11

CODE LENGTH              54

 

This output provides details on the size and nonlinearly of the model.

The block counts refer to GAMS equations and variables, the single counts to individual rows and columns in the problem generated.  The NONZERO ELEMENTS entry refers to the number of nonzero coefficients in the problem matrix.

There are several entries that provide additional information about nonlinear models.

•The NON LINEAR N-Z entry refers to the number of nonlinear coefficient entries in the model.
•The CODE LENGTH entry reports on the complexity of the nonlinearly of the model and is really telling how much code GAMS passes to the nonlinear solver which describes all the nonlinear terms in the model.
•The DERIVATIVE POOL and CONSTANT POOL provide more information about the nonlinear information passed to the nonlinear solver.