On Wed, 2009-10-28 at 23:08 +0100, Ricardo Fernandez wrote:
Hello Pete,
I'm not sure to understand, but my comment could help.
if you have a "Deadline" task for a part of your project (including,
for exemple, task A)
- you can set "Deadline" task as a fixed date milestone
- of course you can't set any predecessor for this fixed date task
- so you can't set A as predecessor (for example "end to start" link)
for "Deadline" task, but...
- you can set "Deadline" task as predecessor (same example ; "start
to end" link) of A
Correct. The way to set up this relationship is to edit your task A and
set up the deadline as a predecessor with a 'SF' relationship. Task A
will then be scheduled so that it ends just prior to the deadline task.
limits for this example :
- even if A is an "as soon as possible" task, it will be scheduled to
"the last moment" before "Deadline". why ? we just wan't it to become
a "not after" task.
ASAP just means that the task start date will float based on predecessor
relationships. Planner schedules all tasks (without assigned resources)
assuming that a single resource will work at 100% capacity for the
duration, and sets the start and end dates accordingly. If you want to
change the start date on a task with a 'SF' relationship, you should
assign a resource and adjust the resource units to something less than
100%.
- you can't anticipate A setting it to fixed date (today for
example). why ?
see above
- you can't set any other predecessor to A (a current task ending
tomorrow, linked "end to start", for example), even if A has been
scheduled on next year. why ?
Well, if you've set the finish date for task A with a SF or FF
relationship, then we need to let the start date float in order for the
scheduling algorithm to work.
If you created a task B, you could set task A as a predecessor with a SF
or FF relationship. In this way, you're essentially scheduling from the
deadline back to the present day.
I agree that external constraints are decisive in project scheduling
and that Planner constraints rules are too much restrictive.
but it's not an easy problem, and coding realy accurate rules could be
an infinite task.
so just try to use such links with parsimony
Regards,
Ricardo FERNANDEZ
______________________________________________________________________
De : Alexandre Franke <alexandre franke gmail com>
Envoyé : 25/10/2009 13:14:00 +0100
À : planner <planner-list gnome org>
Objet : Planner-list predecessors for fixed date tasks
On Sun, Oct 25, 2009 at 5:42 AM, pete davidson <caitifty gmail com> wrote:
Hi all
Hi,
I'm trying to use Planner to manage academic grant applications. As such,
there's a number of key tasks whose dates are externally set and
non-negotiable (such as the date the grant must be submitted to the funding
agency, or the date a letter of intent is due to the funding agency). I've
been 'locking' these dates by creating a milestone task (eg "Submit grant")
with a schedule of 'on fixed date' on the required date.
The problem I'm having is when I try and link these milestone tasks to the
rest of the tasks in the project by setting a predecessor. This produces
the error "You cannot add a relationship to a task with a Must Start On
constraint." I've also tried using a one-day task instead of a milestone
task, but get the same error.
The problem here is with the meaning of the predecessor relationship.
If you set A as a predecessor of B, it means that you cannot start
working on B until A is done. So what would happen if you start A on
oct 26th, need 4 days to finish it and set B on oct 28th (fixed date)?
That wouldn't make any sense because you'd need to work on B but you
couldn't since A isn't done yet.
This has nothing to do with the fact that it's a milestone.
Is there another approach to dealing with externally set fixed dates that
I'm missing, or a way to set milestone tasks which allows linking to other
tasks?
You can do it without the predecessor relationship, I think it's the
way that would make the most sense.
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