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Do not resource level flag / Must Start On constraint.

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Evgeny Z.
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Dear all,

I still sort of feel that for my applications it would be difficult to work  with Spider without a feature  to make certain tasks so high priority, that resource leveling cannot move them at all. So, something like “do not resource level” flag or may be even Must Start On constraint.

In case several of such activities create a resource conflict, which Spider cannot resolve, I would want it to give an error message.

I would use this feature to put in the schedule activities, which are determined/scheduled outside of Spider and therefore Spider just has to respect those (and take them into account). e.g.

  • Vacations
  • Visits of presidents etc
  • Trainings, scheduled externally
  • Actually any activity, which is not influenced by a scheduler, however which he has to take into account.

At the moment the only way to achieve this, would be to create activity with very high priority, imposed by “Unachievable NLT constraint”, however this is still not exactly the same as “do not resource level” flag.

What do you think?

Replies

Rafael Davila
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Joined: 1 Mar 2004
Posts: 4780

As initially proposed by Vladimir it is starting to look like it is easier and safer to:

  • Just make an exception in the resource calendar at the "must" activities time period and do not assign resources to activities that are must. This way overallocations are avoided and resources may interrupt jobs they are doing for attending seminar, conference of president. In any case these activities usually do not represent real work.
    • All you need is a single exception per "must activity" you assign to the calendars of resources that will be required for the "must activity". The trick is that you will not assign these resources to the "must activity" but will mark them as unavailable via the calendar exception. It is easy to report calendar exception assignments as well as to make changes to the exceptions that will be automatically applied to all calendars with such exception. 
  • You can create additional dummy resource and assign this resource to "must" activities, then create resource center adding dummy resource to the real one, and then get reports on resource center. You will get full information on total resource workload.
  • It is not necessary to apply special calendars to dummy resources in the model. Assign 24/7 calendar with no exceptions. In any case they shall be assigned to activities that have special calendars and dates and will be used only on these activities.

Best Regards,

Rafael

Evgeny,

there are many ways to achieve the same in Spider Project.

Using high priority activities for exceptions will require to use variable resource assignments on all other activities or set other activities as splitable. It will make calculations slower and may take more time than entering time exceptions for several resources, creating dummy resources and resource centers.

Exceptions activities with manually entered dates shall be created in both cases.

I don’t understand what do you mean by succeeding exception. I understoof that exception is an activity that does not depend on anything in the project (like visit, vacation, etc.).

If it is project activity then other competing activities shall become splitable with lower priority.

The problem with interruptible activities may be created if other activities (not exception activities) have higher priority. It may lead to unwanted interruptions.

I think that an approach that I suggested is more safe but other described above may work also.

Below is an example of the same project when calendar exceptions are not used but activities are set as splittable.

 

 photo Interr_zps1cb7982c.png

Evgeny Z.
User offline. Last seen 11 weeks 6 days ago. Offline
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Vladimir,

I just made a comparison table to show 2 different approach to handle exception:

  • As a very high priority activity
  • As a calendar exception.

Assumption: there is a need to show the exception in the report using the method suggetsed by you. 

Is the table correct in your view?

 Using calendar exceptionUsing high priority activity
Need for activity to show exceptionYesYes
Need for one extra dummy resource per real resourceYesNo
Need for one extra resource center per real resource to combine every real resource with dummy resource for reporting purposesYesNo
Need for Calendar exceptionYesNo
Need for Separate calendar for every resourceYesNo
Need to manually synch duration and start time of exception and activity, which shows exceptionYesNo
Need to Manually update dates of the succeeding exception, if preceding activities have changedYesNo

Regards.

 

Evgeny

I would suggest this

 photo DummyP_zps49e64ac2.png When resource assignments are variable it is better to use activity of Productivity type.

Evgeny Z.
User offline. Last seen 11 weeks 6 days ago. Offline
Joined: 13 Jan 2008
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Vladimir,

I have made an example of what I think you mean.

Is it correct?

https://docs.google.com/file/d/0B1FBt_G3gCVqajhLdlZaa2J4OU0/edit

 

 photo Exceptions_zpsc516619a.png

Rafael Davila
User offline. Last seen 5 hours 6 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780

Thanks Vladimir,

Very easy indeed.

Rafael

Evgeny and Rafael,

it is not necessary to apply special calendars to dummy resources in the model I described. I would assign 24/7 calendar with no exceptions. In any case they shall be assigned to activities that have special calendars and dates and will be used only on these activities.

So it is much easier than Evgeny described: Show certain exceptions as activities, create dummy resources with large quantity (Rafael is right), assign these resources to exception activities, create resource centers combining real and dummy resources.

Now any report may be created including those that Evgeny described. If necessary, dummy activities may be hidden.

Rafael Davila
User offline. Last seen 5 hours 6 min ago. Offline
Joined: 1 Mar 2004
Posts: 4780

When Vladimir said: By the way you can create additional dummy resource and assign this resource to "must" activities, then create resource center adding dummy resource to the real one, and then get reports on resource center. You will get full information on total resource workload.

  • I believe he also meant to say use additional dummy resource; for Visits of presidents etc, Trainings, scheduled externally and Actually any activity, which is not influenced by a scheduler, however which he has to take into account.
    • The dummy resource is a meeting resource, this means shall be on every team on "must" activities and the activities will be scheduled to happen only when all meeting resources are available.
    • Meeting Resource shall be assigned a special calendar where availability is only on dates they must be assigned.
    • Meeting Resource shall be of a very high quantity as it not to delay activities because of quantity limits but to use it only to schedule activities when all meeting resources are available because of a common calendar. 
    • A must date constraint will not do it, it will allow impossible assignments.

Say you fix Rafael meeting in Cuba this Monday 7am GMT, Rafael meeting in Sochy this Monday 7am GMT, by brute force it is possible but it is wrong. 

  • You assign Rafael and Meeting Resource to Cuba Meeting and do the same for Sochi meeting.
  • The meeting resource will not prevent both activities to happen simultaneously because it was set very high quantity it is the single Rafael resource that will prevent the two meetings to be scheduled the same day. 

Say you need three activities to happen on Monday. 

  • The meeting resource will not prevent any activity to happen simultaneously because it was set very high quantity but activities will be scheduled to happen when Meeting Resource and activities resources are available at the same time. Assign the activities a high priority so they will not be scheduled on Monday if for some reason is imposible otherwise they will. 

For Vacations the calendars exceptions is enough for resources to be assigned on vacations and the dummy resource is enough to show vacation activities.

  • To show a calendar as an activity you assign the dummy resource to the activity and it will be scheduled only when available based on his calendar, the dummy resource will be available on vacation calendar.

Whenever you adjust any calendar the above activities would be automatically adjusted. The idea on RCP - Resource Critical Path scheduling is on making sure there are no resource overload if you fix by brute force activities it will not work.

Best Regards,

Zulu Time

Evgeny Z.
User offline. Last seen 11 weeks 6 days ago. Offline
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Vladimir,

using calendar exceptions is one of the possibilities, but in my eyes it has several disadvantages:

  • It would require creation of the separate calendar for every resource.
  • It will be very difficult to manage if unmovable activities are a bit more complex than just a single activity. E.g. if there are several activities, linked to each other. In this case if one extends duration of the 1st activity, than he also would have to change the start date of the 2nd activity (calendar exception) etc. So it becomes a bit messy to manage
  • There is no report available to show all exceptions for a specific resource.
  • The way to produce a report on the resource workload suggested by you would work, but it would require a creation of: individual calendar for a resource; calendar exception; separate dummy resource; activity, which falls exactly in the exception; resource center. So, to conclude: this is very difficult to manage as well as to update.

From the other side, the “do not resource level” or “very high priority” activity functionality seems to be already present in the algorithm.  As the “unachievable NLT constraint” or “Consider Portfolio Schedule” features must be using it pretty much. So, may be it is not that difficult to add it formally to Spider?

Regards.

Evgeny

  

Mike Testro
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Hi Evgeny

I would put this type of "interuptions" on a calendar and apply them to the resource. That would over ride the task calendar.

Best regards

Mike Testro

In such cases we just made an exception in the resource calendar at the president visit time period and do not assign resources to activities that are must. This way overallocations are avoided and resources may interrupt jobs they are doing for attending seminar, conference of president. In any case these activities usually do not represent real work.

By the way you can create additional dummy resource and assign this resource to "must" activities, then create resource center adding dummy resource to the real one, and then get reports on resource center. You will get full information on total resource workload.