Assigning variable and equation attributes

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One may specify initial values for the attributes of equations and variables. Those new data statements follow the syntax for parameters or tables by adding an additional dimension to specify the specific data attribute but appear in the context of the variable and equation definitions or a Table statement.

The items that can be entered are the upper, lower and fixed bounds (.up, .lo, .fx); starting values (.l); scaling factors (.scale); marginals (.m); and priorities (.prior for variables only).

The format is an extension of the variable and equation commands of one of two forms.

•The conventional variable and equation statements can be augmented with a parameter like section where values are enclosed in between /'s as follows

 

    Variable x1(j) my first  / j1.up 10 , j1.lo 5, j1.scale 20, jl.l 7, j1.m 0 /;

    Equation landconstrain(landtype) my land constraints

                          / cropland.scale 20, cropland.l 7, cropland.m 100 /;

 

•A table structure can be used The conventional variable and equation statements can be augmented with a parameter like section where values are enclosed in between /'s as follows

          variable table x(i,j) initial values

                                  l      m

         seattle.  new-york    50

         seattle.  Chicago    300

         san-diego.new-york   275

         san-diego.chicago         0.009;

 

    Equation table landconstrain(landtype) my land constraints

                    Scale   l   m                                                  

         cropland    20     7  100

         Pasture     10     6   30;