Quick start - Gams

Notes
Pdemand.. P =g= 6 - 0.3*Qd; (econequil.gms)
r1.. ba * so4 =e= 1 ; (nonlinsys.gms)
The general form of these statements are
Equationname.. algebra1 equationtype algebra2 ;
where an equation with that name must have been declared (have appeared in and
equation statement)
the .. appears just after the equation name
the algebraic expressions algebra1 and algebra2 can each be a mixture of
variables, data items and constants
the equationtype is the =E=, =L=, and =G= discussed above.
a ; ends the statement
All equations must be specified in .. notation before they can be used.
Some model equations may be specified in an alternative way by including upper or
lower bounds as discussed in the Variables, Equations, Models and Solves chapter.
.. specification statements may be more complex including more involved algebra as
discussed later in this tutorial and in the Calculating Items chapter.
It may be desirable to express equations as only being present under some conditions as
discussed later in this tutorial and in the Conditionals chapter.
Model
Once all the model structural elements have been defined then one employs a MODEL statement
to identify models that will be solved. Such statements occur in the each of the three example
models:
Notes
MODEL farmPROBLEM /ALL/; (optimize.gms)
MODEL PROBLEM /Pdemand.Qd, Psupply.Qs,Equilibrium.P/; (econequil.gms)
Model wall / all / ; (nonlinsys.gms)
The general form of these statements are
Courtesy of B.A. McCarl, October 2002 9