The NETFLOW Procedure

Suppose the 25-inch screen TVs produced at factory 1 in May can be sold at either shop with an increased profit of 40 dollars each. What is the new optimal solution? Because only arc costs have been changed, information about the present solution in DUALOUT= dual4 and CONOUT= con4 can be used as a warm start in the following PROC NETFLOW run. It is still necessary to specify CONDATA= con3 SPARSECONDATA RHSOBS= 'CHIP/BO LIMIT', since the CONDATA= data set is always read.

  title 'Using a Constrained Solution Warm Start';
  title2 'Production Planning/Inventory/Distribution';
  data new_con4;
     set con4;
     oldcost=_cost_;
     oldflow=_flow_;
     oldfc=_fcost_;
     if _tail_='f1_may_2'
        & (_head_='shop1_2' | _head_='shop2_2')
        then _cost_=_cost_-40;
     run;

proc netflow
   warm
   arcdata=new_con4
   dualin=dual4
   condata=con3
   sparsecondata
   rhsobs='CHIP/BO LIMIT'
   dualout=dual5
   conout=con5;
run;
 quit;

proc print data=con5 heading=h width=min;
sum _fcost_;
var _tail_ _head_ _capac_ _lo_ _supply_ _demand_ _name_ _cost_ _flow_ _fcost_;
run;

proc print data=con5 heading=h width=min;
   sum oldfc;
   var oldcost oldflow oldfc diagonal factory key_id mth_made _anumb_ _tnumb_;
run;

proc print data=dual5;
run;

The following messages appear on the SAS log: