2017-07-06 12:08:40 UTC
Read the following:
PERT++ (An enhanced edition of the program or project evaluation and
review technique that includes Statistical PERT) in Delphi and
FreePascal is here..
Authors: Amine Moulay Ramdane that have implemented PERT, Robert
Sedgewick, Kevin Wayne.
This program (or project) evaluation and review technique do include
includes Statistical PERT, it is a statistical tool, used in project
management, which was designed to analyze and represent the tasks
involved in completing a given project.
PERT++ permits also to calculate:
- The longest path of planned activities to the end of the project
- The earliest and latest that each activity can start and finish
without making the project longer
- Determines “critical” activities (on the longest path)
- Prioritize activities for the effective management and to
shorten the planned critical path of a project by:
- Pruning critical path activities
- “Fast tracking" (performing more activities in parallel)
- “Crashing the critical path" (shortening the durations of critical
path activities by adding resources)
- And it permits to give Risk for each output PERT formula
PERT is a method of analyzing the tasks involved in completing a given
project, especially the time needed to complete each task, and to
identify the minimum time needed to complete the total project. It
incorporates uncertainty by making it possible to schedule a project
while not knowing precisely the details and durations of all the
activities. It is more of an event-oriented technique rather than start-
and completion-oriented, and is used more in projects where time is the
major factor rather than cost. It is applied to very large-scale,
one-time, complex, non-routine infrastructure and Research and
PERT and CPM are complementary tools, because "CPM employs one time
estimate and one cost estimate for each activity; PERT may utilize three
time estimates (optimistic, most likely, and pessimistic) and no costs
for each activity. Although these are distinct differences, the term
PERT is applied increasingly to all critical path scheduling
This PERT library uses a CPM algorithm that uses Topological sorting to
render CPM a linear-time algorithm for finding the critical path of the
project, so it's fast.
You have to have a java compiler, and you have first to compile the java
libraries with the batch file compile.bat, and after that compile the
Delphi and Freepascal test1.pas program.
Here is the procedure to call:for PERT:
procedure solvePERT(filename:string;var info:TCPMInfo;var
The arguments are:
The filename: is the file to pass, it's is organized as:
The first line is the number of jobs, the rest of each of the lines are:
three time estimates that takes the job (optimistic, expected, and
pessimistic) and after that the number of precedence constraints and
after that the precedence constraints that specify that the job have to
be completed before certain other jobs are begun.
info: is the returned information, you can get the job number and the
start and finish time of the job in info[i].job and info[i].start and
info[i].finish, please look at the test.pas example to understand.
finishTime: is the finish time.
criticalPathStdDeviation: is the critical path standard deviation.
I have also provided you with three other functions, here they are:
function NormalDistA (const Mean, StdDev, AVal, BVal: Extended): Single;
function NormalDistP (const Mean, StdDev, AVal: Extended): Single;
function InvNormalDist(const Mean, StdDev, PVal: Extended; const Less:
For NormalDistA() or NormalDistP(), you pass the best estimate of
completion time to Mean, and you pass the critical path standard
deviation to StdDev, and you will get the probability of the value Aval
or the probability between the values of Aval and Bval.
For InvNormalDist(), you pass the best estimate of completion time to
Mean, and you pass the critical path standard deviation to StdDev, and
you will get the length of the critical path of the probability PVal,
and when Less is TRUE, you will obtain a cumulative distribution.
I have also included a 32 bit and 64 bit windows executables called
PERT32.exe and PERT64.exe (that take the file, with a the file format
that i specified above, as an argument) inside the zip, it is a very
powerful tool, you need to compile CPM.java with compile.bat before
The very important things to know about PERT is this:
1- PERT works best in projects where previous experience can be relied
on to accurately make predictions.
2- To not underestimate project completion time, especially if delays
cause the critical path to shift around, you have to enhance with point
number 1 above or/and management time and resources can be applied to
make sure that optimistic and most likely and pessimistic time estimates
of activities are accurate.
Also PERT++ zip file includes the powerful Statistical PERT, Statistical
PERT is inside Statistical_PERT_Beta_1.0.xlsx microsoft excel workbook,
you can use LibreOffice or Microsoft Office to execute it, after that
pass the output data of Statistical PERT to CPM library, please read the
Readme.CPM to learn how to use CPM library, and please read and learn
about Statistical PERT on internet.
You can download PERT++ from:
Have fun with it !
Language: FPC Pascal v2.2.0+ / Delphi 7+: http://www.freepascal.org/
Operating Systems: Windows,
Required FPC switches: -O3 -Sd -dFPC -dFreePascal
-Sd for delphi mode....
Required Delphi switches: -$H+ -DDelphi
For Delphi XE-XE7 use the -DXE switch
Amine Moulay Ramdane.