/***********************************************************************************
* This program is taken from the following book. If using please cite it as: *
* Emrouznejad, A. and W. Ho (2012). Applied Operations Research with SAS, *
* CRC Press: Taylor Francis Ltd, ISBN: 9781439841303. *
* For details please visit: http://www.sas-or.com. *
************************************************************************************/
*Program 2.3: Using PROC OPTMODEL for Transportation problem;
option nodate ;
%let _title=’solution to exercise 2.3′;
%let _data=’c:\sasor\data2_3_exercise.txt’;
* The data handling macro;
%macro data;
* Import text tab delimited data file to SAS data file;
proc import
datafile=&_data
out=dcost
dbms=tab
replace;
getnames=yes;
run;
%mend data;
%macro model;
* Starting OPTMODEL Procedure;
proc optmodel;
* Define sets;
set SUPPLIERS;
set CUSTOMERS={1..5};
* Define parameters;
number demand{CUSTOMERS};
number supply{SUPPLIERS};
number cost{SUPPLIERS, CUSTOMERS};
* Define variables;
var X{SUPPLIERS, CUSTOMERS} >= 0;
* Load the supplier set and their amount of supply;
read data dcost (where= (supply ne .))
into SUPPLIERS=[Supplier] supply[Supplier]=col(“supply”);
* Load the customer set and their demand;
read data dcost (where= (supply eq .)) into
{c in CUSTOMERS} ;
* Load the cost of shipment from each supplier to each customer;
read data dcost (where= (supply ne .))
into SUPPLIERS=[Supplier]
{c in CUSTOMERS} ;
* Define objective function;
min obj = sum{s in SUPPLIERS, c in CUSTOMERS} cost[s,c]*x[s,c];
* Define constraints;
con req_supply{s in SUPPLIERS}:
sum{c in CUSTOMERS} x[s,c] <= supply[s];
con req_demand{c in CUSTOMERS}:
sum{s in SUPPLIERS} x[s,c] >= demand[c];
con zero{c in CUSTOMERS, s in SUPPLIERS : cost[s,c]=1E10}: x[s,c]=0;
* Solve the model;
solve with lp/solver=primal;
* Create optimum values in a SAS dataset ‘optimout’;
create data optimout
from [SUPPLIERS CUSTOMERS]
={s in SUPPLIERS, c in CUSTOMERS: x[s,c]^=0}
amount=x;
* End of OPTMODEL Procedure;
quit;
%mend model;
* The report writing macro;
%macro report;
* report the results in a tabulated form;
proc tabulate data=optimout;
title &_title;
class SUPPLIERS CUSTOMERS ;
var amount;
table SUPPLIERS =” Suppliers”,
CUSTOMERS*amount*sum
/ BOX=’Amount of suppliers to customers’ ;
run;
%mend report;
* The ortrans macro for transportation problem;
%macro ortrans;
%data;
%model;
%report;
%mend ortrans;
%ortrans;
/****************************************************************************
******************************END of the program*****************************
****************************************************************************/
