Example 5.6: Nonstandard Precedence Relationships

The NETDRAW Procedure

Example 5.6: Nonstandard Precedence Relationships

This example illustrates the use of the LAG= option to indicate nonstandard precedence relationships between activities. Consider the widget manufacturing project described in the earlier examples. Some of the precedence constraints between the activities may be nonstandard or have a nonzero lag value. For example, the activity `Init. Prod.' may not be able to start until 2 days after the completion of the activity `Facility'. The Network data set is displayed in Output 5.6.1. The variable lagdur indicates the type of relationship between the activities specified in the variables task and succ.

The following statements invoke PROC NETDRAW with the LAG= option. The resulting network diagram is shown in Output 5.6.2.

   title 'Widget Manufacture';
   title2 h=1.5 'Nonstandard Precedence Constraints';
   proc netdraw graphics data=widglag;
      actnet / act=task
               succ=succ
               lag=lagdur
               pcompress
               htext=3 boxht=3 arrowhead=2
               xbetween=7 ybetween=9
               centerid
               separatearcs;
      run;

Output 5.6.1: Network with Nonstandard Precedence Constraints

Widget Manufacture

Network Data Set

Obs	task	days	succ	lagdur
1	Approve Plan	5	Drawings
2	Approve Plan	5	Anal. Market
3	Approve Plan	5	Write Specs
4	Drawings	10	Prototype
5	Anal. Market	5	Mkt. Strat.
6	Write Specs	5	Prototype
7	Prototype	15	Materials	ss_9
8	Prototype	15	Facility	ss_9
9	Mkt. Strat.	10	Test Market
10	Mkt. Strat.	10	Marketing
11	Materials	10	Init. Prod.
12	Facility	10	Init. Prod.	fs_2
13	Init. Prod.	10	Test Market
14	Init. Prod.	10	Marketing
15	Init. Prod.	10	Evaluate
16	Evaluate	10	Changes	ss_6
17	Test Market	15	Changes	ff_3
18	Changes	5	Production
19	Production	0
20	Marketing	0

Output 5.6.2: Network Diagram with Nonstandard Prcedence Constraints

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