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OS/2 Shareware BBS: 10 Tools
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LIFE-1.02
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EXAMPLES
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SCHEDULE.DOC
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1996-06-04
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A LITTLE PERT SCHEDULER
NAME
schedule: A demo using constraints on sorts and residuation to achieve
performance and conciseness.
USAGE (see examples)
In a query, declare the tasks you consider and the information you have
about them:
A1 = task( duration => 34, prerequisites => [A2,A3]), ...
%%% A2 and A3 must be defined in the same query, and are references
%%% to tasks that must be performed before A1
when all tasks are declared, they may be visualized with
visAllTasks(List_of_Tasks)?
See the sample inputs in schedule.lf
FILES
The file schedule.lf contains the scheduler.
DESCRIPTION
All constraints are set during the type check, and they are released as soon
as if enough information is known.
Each time a task is defined, the earlyStart field is initialized with the
earlyCalc function. This function takes the list of prerequisites as argument,
and residuates on the tasks which are still undefined.
Defining the task also sets a set of constraints on the lateStart field of
the prerequisites. Here again, these constraints residuate until enough
information is known.
This way, every necessary computation is done once and only once.
AUTHOR
Bruno Dumant
Copyright 1992 Digital Equipment Corporation
All rights reserved