Example - Complete Decomposition of Selected Expression in Equation

This illustrates what happens when you click on the "Decompose Selected Expression" popup menu item which shows when you right-click on a linearised equation, and then ask for the complete decomposition.

Only the selected expression (rather than the RHS or LHS or whole equation) is decomposed. Otherwise the complete decomposition works in the same way as for the complete decomposition of one side or of the whole of the equation. Knowing this, if you understand how the complete decomposition of one side of an equation works, you will be able to anticipate how the complete decomposition of a selected expression in an equation works.

When you do the complete decomposition of a selected expression, you always see separate terms/toggles corresponding to each of the variables in the expression. You also see a last term/toggle which shows the values of the whole expression you have selected. This last toggle is always called EXP to indicate that this shows the value of the whole expression.

Example

Equation E_x3 # Source-specific commodity demands #

(all,c,COM)(all,s,SRC) x3(c,s) - a3(c,s) =

x3_s(c) - SIGMA3(c) * [p3(c,s) + a3(c,s) - p3_s(c)] ;

Suppose that you select the part of the RHS beginning with SIGMA3 and going to the closing ] (as shown in bold above) and then ask for the complete decomposition of this expression.

There are only 3 variables occurring in this expression, namely p3, a3 and p3_s. Hence, in the complete decomposition, you will see the following 4 values:

1 the terms in the expression involving p3, namely SIGMA3(c) * p3(c,s),

2 the terms in the expression involving a3, namely SIGMA3(c) * a3(c,s),

3 the terms in the expression involving p3_s, namely -SIGMA3(c) * p3_s(c), and

4 the whole expression, namely SIGMA3(c) * [p3_s(c) + a3(c,s) - p3(c)].

The Formulas you will see in the Evaluate memo on the AnayseGE form are:

Formula (All,c,COM)(All,s,SRC) TempCoeff("p3",c,s) = SIGMA3(c) * p3(c,s);

Formula (All,c,COM)(All,s,SRC) TempCoeff("a3",c,s) = SIGMA3(c) * a3(c,s);

Formula (All,c,COM)(All,s,SRC) TempCoeff("p3_s",c,s) = -SIGMA3(c) * p3_s(c);

Formula (All,c,COM)(All,s,SRC) TempCoeff("EXP",c,s) =

SIGMA3(c) * [p3_s(c) + a3(c,s) - p3(c)]

Notice that the toggle EXP is used for the whole expression. [The other toggles are the names of the variables, as happens with all complete decompositions of all or part of an equation.] The toggle names and their associated values are as follows:

You might like to compare this with the intelligent decomposition of this expression in the equation and/or the complete decomposition of the RHS of this equation.

Exactly What Are You Seeing?

As with all decompositions, if you are at all unsure exactly what values you are seeing in each toggle, you can look at the Exxx header on the ViewHAR form or in the Evaluate memo on the AnalyseGE form.

URL of this topic: www.copsmodels.com/webhelp/analysege/hc_decompcmp.htm

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