ALTERA control card. Thus, right-hand side and matrix elements can both
be changed. It is important to remember that any matrix coefficient
including zero, must be entered explicitly in the original matrix section
to be modified by ALTERA.
 A sample input deck for using this strategy is shown in Figure 8.
This is SAMPLE PROBLEM NUMBER 1 from Section 4 that is used. In this
example we assume that region 1 places a tariff on the commodity C
that is imported from region 2. We want to project what the impact will
be on trade, production, consumption, and prices if tariffs of different
amounts are applied. In particular, we are seeking solutions for tariffs
of .2, .4, and .6 in monetary units.
 The solution results are shown in Figure 9. We will just consider
the Primal-Dual Solution Output since this gives us the information we
are really interested in. Several observations can be made. First of
all, an export tariff of the magnitude considered here did not change
the composition of the set of activities which come into the solution at
a positive level. It does, however, change the numerical values of all
of these variables, including both prices and quantities. This demonstrates
the high degree of interdependency in an international trade market such
as this. As one would expect, the amount imported by region 1 declines
with each increase in the tariff. Also, the domestic equilibrium price
increases in region 1 according to standard theory. A discriminating
tariff such as this, against region 2 has the effect of increasing the
level of imports from region 3. As a general conclusion, it would take
a much stiffer tariff to change the pattern of international trade
altogether, but the changes investigated by the model do have an impact
on the magnitudes of the market variables.
 The above demonstrates the kind of analysis that can be done with
this coefficient change procedure. In addition to tariffs, such things
as import quotas, fixed exogenous supplies of resources, fixed demands,
and even whole demand or supply functions can be established and changed.
Thus, we have a fairly comprehensive tool for model analysis to restart
a problem from a basis created by the user or generated by a previous
run. Experience with the RANDQP-LCRAND program, suggests that restarting
from a previous basis may not be as much a time saver as it is with
traditional linear programming algorithms. The control program used in