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Longest Path with Mixture of Positive and negative float

9 replies [Last post]
Haresh Jayanth
User offline. Last seen 6 years 30 weeks ago. Offline
Joined: 24 Aug 2006
Posts: 219

Dear All,

My program is showing longest path in P6 , with some activties which has a positive float of 135 days also, as well as Zero days float. How could it be possible to generate longest path with positive float and zero float.

Can anybody explain.

regards,

 

Haresh Jayanth - PMP - Planning Manager

 

 

Replies

Ronald Winter
User offline. Last seen 3 years 27 weeks ago. Offline
Joined: 4 Jan 2003
Posts: 928
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Haresh,

 

P3’s version of longest path has nothing to do with Total Float.  Only the forward pass calculations are considered.  Once you understand how longest path is calculated, then you will see this fact.  Try a paper of mine at http://ronwinterconsulting.com/published.htm called, “Longest Path Value” for more on this interesting subject.  Good luck!

Kamal Joshi
User offline. Last seen 2 years 21 weeks ago. Offline
Joined: 29 Nov 2004
Posts: 9

Its possible to have positive Float on the activities falling in Critical Path, when there are multiple critical paths on the program. Probably the reason stated ealier on Constraints given on activities or its Critical Successors/ Predecessors OR your activities showing 136 float have Actual Dates fed on.

Nathaniel Cagara
User offline. Last seen 5 years 24 weeks ago. Offline
Joined: 29 Jul 2005
Posts: 6

check activities that have mandatory constraints.

total float of activities in a path that leads to a mandatory constrainst are calculated relative to mandatory constraint date and not based on project finish date.

Paul Naughton
User offline. Last seen 10 years 37 weeks ago. Offline
Joined: 12 Jul 2006
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Are you looking at a longest path over multiple projects or a single file?

Gary Whitehead
User offline. Last seen 5 years 15 weeks ago. Offline

check for:

 

project constraints

activity constraints

different calendars

that you are using the default 'longest path' filter

Mike Testro
User offline. Last seen 26 weeks 3 days ago. Offline
Joined: 14 Dec 2005
Posts: 4418

Hi Haresh

When diod you last reschedule the project?

Do you have any restraint flags on the tasks?

Are any tasks set ALAP?

Does every task have at least one outgoing link?

And as Stefano says - check your calendars particularly if you have calendars attached to resources.

Best regards

Mike Testro

Stefano Bignozzi
User offline. Last seen 12 years 27 weeks ago. Offline
Joined: 30 May 2007
Posts: 13

Different calendars?

Haresh Jayanth
User offline. Last seen 6 years 30 weeks ago. Offline
Joined: 24 Aug 2006
Posts: 219

Dear Rockzy,

The option for longest path is kept " Total float = 0" , still i am getting longest path with positive float of 136 days also along with 0 days float activity, what would be any other reasons.......

 

regards,

 

Haresh Jayanth

Rockzy Sales
User offline. Last seen 13 years 34 weeks ago. Offline
Joined: 19 Dec 2010
Posts: 19
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Hi,

this is interesting, isn't zero float activities should be in the longest path (if this is also the critical path)...

but for 135 days float? check P6 options...

 

cheers,

the Rock