The dependency graph behind auto-scheduling (GanttEx.Scheduler) and the
critical path (GanttEx.CriticalPath).
Only schedulable tasks take part: tasks and milestones, and projects without children. Projects with children get their dates from their descendants, so:
- a link from a project depends on every schedulable descendant of it
- a finish-to-start or start-to-start link to a project applies to each of its schedulable descendants
Lags are in the duration unit of the store, using the calendar of the task being scheduled.
iex> store = GanttEx.Store.new!(
...> [%{id: 1, start_date: ~D[2025-01-06], duration: 2}, %{id: 2, start_date: ~D[2025-01-06], duration: 1}],
...> [%{id: 1, source: 1, target: 2, lag: 1}]
...> )
iex> GanttEx.Dependency.order(store)
[1, 2]
iex> task = GanttEx.Store.get_task(store, 2)
iex> GanttEx.Dependency.earliest_start(store, task)
~N[2025-01-09 00:00:00]Summary
Functions
Returns the earliest start the links of task allow, or nil when no link
constrains it.
Returns the latest end of source that does not delay successor through
link, given the successor's latest start and end.
Returns the links that constrain task: links to the task itself, plus
finish-to-start and start-to-start links to its ancestor projects.
Returns the schedulable task ids ordered so that every task comes after the tasks it depends on (ties keep the tree order). Tasks in a cycle, which links between a project and its own descendants can create, are appended in tree order.
Returns the links whose source is task or one of its ancestor projects.
Returns true when the dates of task are scheduled (not rolled up).
Returns the ids of the schedulable tasks, in tree order.
Returns the schedulable tasks a link source stands for.
Returns the earliest start of task allowed by one incoming link.
Functions
@spec earliest_start(GanttEx.Store.t(), GanttEx.Task.t()) :: NaiveDateTime.t() | nil
Returns the earliest start the links of task allow, or nil when no link
constrains it.
@spec finish_bound( GanttEx.Store.t(), GanttEx.Task.t(), GanttEx.Link.t(), NaiveDateTime.t(), NaiveDateTime.t() ) :: NaiveDateTime.t()
Returns the latest end of source that does not delay successor through
link, given the successor's latest start and end.
@spec incoming(GanttEx.Store.t(), GanttEx.Task.t()) :: [GanttEx.Link.t()]
Returns the links that constrain task: links to the task itself, plus
finish-to-start and start-to-start links to its ancestor projects.
@spec order(GanttEx.Store.t()) :: [GanttEx.Task.id()]
Returns the schedulable task ids ordered so that every task comes after the tasks it depends on (ties keep the tree order). Tasks in a cycle, which links between a project and its own descendants can create, are appended in tree order.
@spec outgoing(GanttEx.Store.t(), GanttEx.Task.t()) :: [GanttEx.Link.t()]
Returns the links whose source is task or one of its ancestor projects.
@spec schedulable?(GanttEx.Store.t(), GanttEx.Task.t()) :: boolean()
Returns true when the dates of task are scheduled (not rolled up).
@spec schedulable_ids(GanttEx.Store.t()) :: [GanttEx.Task.id()]
Returns the ids of the schedulable tasks, in tree order.
@spec source_ids(GanttEx.Store.t(), GanttEx.Link.t()) :: [GanttEx.Task.id()]
Returns the schedulable tasks a link source stands for.
@spec start_bound(GanttEx.Store.t(), GanttEx.Task.t(), GanttEx.Link.t()) :: NaiveDateTime.t() | nil
Returns the earliest start of task allowed by one incoming link.
- finish-to-start: starts after the source ends (plus lag)
- start-to-start: starts after the source starts (plus lag)
- finish-to-finish: ends after the source ends (plus lag)
- start-to-finish: ends after the source starts (plus lag)