Table 2.--Transportation cost matrix

 Destination region
 Source 1
 1 2 3
 region

 1 0 2.1 2.5
 2 2.1 0 3.0
 3 2.5 3,0 0


 In this case, and in many cases, the matrix is symmetric and has
zeros along the diagonal. The inclusion of items such as marketing mar-
gins, import tariffs, etc. can result in a very different cost of trading
being entered in the model.
 All possible flows of trade between the three regions are allowed
in the model. Often, many trade flow possibilities can be left out of
the model based on previous knowledge.
 The monetary unit can be dollars, yen, or whatever you like. It
does not affect the presentation here. Choice of monetary units, deflator
etc. is a problem in modeling of the type done with LCRAND but is not
considered in this manual.


4.1.2 Input data--As in the MPS programming systems, we must choose names
for the rows and columns of the A matrix. It is desirable that the names
chosen be meaningful to the user, as a well chosen "system" for naming
can save unnecessary confusion and mistakes. Frequently, a workable
scheme involves assigning a certain meaning to each position in the name
and then establishing a letter code to signify different regions, commodity:
etc. For this problem, we will use the following system.
 R regional (signifies a row name)
 X quantity (signifies a column name)
 D demand
 S supply
 C commodity
 T trade
 1,2,3 region