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Incorrect duration

9 replies [Last post]
Fri, 2009-06-05 06:03
Khuong Do
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Hi all.
I’m working with P6.2.
Sometimes the activity duration change to a decimal number, like 505.01 days. I fix it to 505.00d but after some days it changes back to 505.01d. I have no idea with this weird error.
Doese anyone have the same issue like me?

Regards
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Replies

Tue, 2023-12-26 09:27
#1
Rodana Saqallah
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Groups: Civil Engineering, Planning, Claims & Contracting, Women in Planning & Scheduling (WiPS)

hello all

i have issue  ...the original duration for project is less that what should be

actually it should be 260 day but its only 212

i checked calender and all solution that mentiond before


what should i do

8563
new.png

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Tue, 2023-12-26 09:24
#2
Rodana Saqallah
User offline. Last seen 6 weeks 1 day ago. Offline
Joined: 16 Dec 2023
Posts: 1
Groups: Civil Engineering, Planning, Claims & Contracting, Women in Planning & Scheduling (WiPS)

wysiwyg_imageupload::

hello all

i have issue  ...the original duration for project is less that what should be

actually it should be 270 day but its only 212

i checked calender and all solution that mentiond before

 

what should i do

8562
new.png

Top
Tue, 2023-12-26 09:24
#3
Rodana Saqallah
User offline. Last seen 6 weeks 1 day ago. Offline
Joined: 16 Dec 2023
Posts: 1
Groups: Civil Engineering, Planning, Claims & Contracting, Women in Planning & Scheduling (WiPS)

wysiwyg_imageupload::

hello all

i have issue  ...the original duration for project is less that what should be

actually it should be 270 day but its only 212

i checked calender and all solution that mentiond before

 

what should i do

8562
new.png

Top
Sun, 2009-06-07 23:30
#4
Dieter Wambach
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Joined: 15 Jan 2007
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Groups: Petro-Chem / Oil & Gas, TILOS
Khuong Do

If you’ll enter the duration or units value in hours, it should be ok. As I wrote, I only found those rounding errors only in the calculation between display: in days and save: in hours with decimals. No need to change user preferences if you want to enter a value in hours. Just type the value in hours followed by "h" - or your abbreviation for hours, if you modified it.

Regards
Dieter
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Sun, 2009-06-07 22:01
#5
Khuong Do
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Joined: 22 May 2009
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Hi Dieter and Ronald.
Thanks so much for your help.
In brief, the error is due to time conversion from hour to day. If I change to dislay in hour and input value 4040 hours (=505 days) and then display in day for report purpose, Primavera will display duration in day correctly, is it right?

I’m little doubt at this solution. Because I didn’t change the value in "Time Period" in Admin Preference and in User Preference. There is no difference between them.

Regards
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Sun, 2009-06-07 04:29
#6
Dieter Wambach
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Ronald, Vladimir

I agree to Vladimir. When I checked for the size of different projects, I found that big usage (10 to 15 per activity, for whatever reason) of coding has much mor influence on memory consumption.
Another factor are notebook items and relations to documents. It wasn’t that much the size by number of activities.

Regards
Dieter
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Fri, 2009-06-05 18:22
#7
Vladimir Liberzon
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Groups: Accreditation Editors, Board of Advisors, Civil Engineering, GPCCAR Editors, Petro-Chem / Oil & Gas, Regional Representatives, Spider Project Team, TURNAROUND & SHUTDOWN (T/A & S/D)
Ronald,
you wrote:
As bizarre as it sounds, P6 calculates the CPM in minute increments (even 500 day schedules.) Now you can see why Primavera lists 2 GB of memory as a minimum requirement for your computer.

Spider Project calculates schedules in seconds but does not require any special memory. So this is not the reason why P6 needs 2 GB.
Best Regards,
Vladimir
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Fri, 2009-06-05 11:36
#8
Dieter Wambach
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Ronald

I don’t feel like picked. I didn’t mention the units less than an hour. How many digits depends on the settings of the database (in Oracle).

Ronald, I’m sure you are much more experienced than me. I’m a user (since 1994 P3 and 2001 P3e)

In the past I stumbled over the same as Khuong Do and felt unsafe of course. So I tested. Now I’m quite confident in the internal calculation. When I need exact results I let units and durations be displayed in hours with decimals and the dates with minutes.

If you have a look into the database, those fields are defined numeric (17,6) for the MS SQL-server - as far as I know, even more in Oracle.

I’ll have no chance to join the AACE meeting, I hope you’ll show your paper on your home page. It would be great.

Best regards

Dieter

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Fri, 2009-06-05 11:05
#9
Ronald Winter
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Dieter,

I hope that you do not think that I am picking on you. I suspect that you know more about P6 than the current Primavera Development Team. While you are correct in quoting Primavera’s technical manual in stating that P6 calculates the CPM in hours, this clearly is not the case.

Holidays are entered in half hour increments. There would be no reason to do this if the CPM were calculated in hours. Likewise, working day length can be defined in fractions of an hour to (at least) two decimal paces. Durations in the database are stored in hours, but decimal hours accurate down to the microsecond.

I will be delivering a technical paper at the AACEi Annual Conference in July of this year that shows P6 calculating a test schedule down to the even minute. As bizarre as it sounds, P6 calculates the CPM in minute increments (even 500 day schedules.) Now you can see why Primavera lists 2 GB of memory as a minimum requirement for your computer.
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Fri, 2009-06-05 10:41
#10
Dieter Wambach
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Ronald

You are right for my calculation; it’s 14 minutes, not less than one - sorry Khuong Do.

But as the internal calculation is in hours, the overall duration will be ok. For my experience this error just happens in the calculation of the displayed duration. In the past I stumbled over this item as well and checked several times. Result: the calculation in hours was ok. Therefore my suggestion: for an exact check, display durations in hours.

Regards
Dieter
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Fri, 2009-06-05 08:53
#11
Ronald Winter
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Dieter,

Khuong is working in days. 0.01 days is equal to 14.4 minutes; roughly a quarter of an hour. Due to rounding issues, the ’real’ value could be 21 minutes and still display 0.01. I stand with Khuong on this; a $5,000 software package should not be generating one-third of an hour errors. As you pointed out, 500-day schedules consisting of tens of thousands of activities all off by a third of an hour (or more) does not give one a real sense of confidence in the accumulated sum.
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Fri, 2009-06-05 08:16
#12
Dieter Wambach
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Khuong Do

Internally P6 calculates in hours, just to display it calculates hours into days, weeks - whatever you choose as unit. Rounding issues during this calculation may lead to this result. If you’ll need exact figures, you’ll better use hours.

0.01 is less than one minute. Which controlling actions you’ll take to recover? For an activity duration of 500 days it might be a consideration to ignore the decimals.

Regards
Dieter
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