Re: Simple priority scheduling

[Alexandre Franke <alexandre franke gmail com>]

Hey,

On Thu, Mar 12, 2015 at 8:24 AM, Terry Barnaby <terry beam ltd uk> wrote:
> Hi, I have been using planner on and off for a few years now for some
> projects. Its not ideal but works ok for us. The biggest issue though has
> been the lack of some form of automatic scheduling of tasks that share the
> same resource.
> There was the --enable-simple-priority-scheduling build option but
> this did not seem to do much if anything.

Yeah, as far as I know this was more of an experiment, which is why it
is not enabled by default.

> Anyway, we wanted to have some basic priority scheduling for a project
> and after looking around at alternative programs decided to modify
> planner a bit.

Cool!

> So we have implemented a basic priority scheduler, enabled with the
> --enable-simple-priority-scheduling build option. What this does
> is:

If it is good enough, and has no undesirable side effect, we could
enable this by default (and maybe use a
--disable-simple-priority-scheduling if we still want to be able to
disable it, though I'm not sure why we'd want that).

> 1. Has a "scheduling" checkbox in the project dialog to enable
>    the feature. This is saved to/restored from the xml project file.

Are you talking about the project properties dialog that can be
launched from Project → Edit project properties?

> 2. When enabled if there is any degree of clash between two tasks
>    that use the same resource the task with the lowest priority
>    and its dependants is/are moved in time to be after the task with
>    the higher priority.

What kind of move are we talking about here? Is it only computed and
displayed, or is the new start date saved in the file? Will the
scheduling happen everytime I open the file? Everytime I edit a task?

> 3. If the clashing tasks have the same priority, the earliest task
>    in the list of tasks (nearer the top) are deemed to have higher
>    priority than the ones below.

Simple no-nonsense behaviour. I like that. Are there complex cases
where the scheduler messes up or gets lost? E.g. what happens with
lots of dependencies or when several people work on the same task, but
with different calendars? Or any other corner case you might think of…

> At the moment I use a simple toggle button to enable, but an integer
> is stored in the xml file to enable it so it would be possible to
> extend this with various simple algorithms.

Seems fair enough.

> I can provide a patch for this, but I don't have much time to really
> polish it and update the main sources. Some things may need to
> be changed (for example I have modified the mrproject-0.6.dtd file
> it may be better to have an updated version dtd file etc).
> I'm not sure if anyone is actively maintaining the code and/or
> thinks this patch would be a good idea and would like to take the
> patch and update the code ?

Let's say I'm semi-actively maintaining it. The code is not moving
much currently because we're transitionning to GTK+3 and I'm waiting
for GSK to arrive to replace our current gnome-canvas based Gantt
chart.

But sure, your contribution is welcome and I'd be happy to have it merged.

-- 
Alexandre Franke