In this article:
Highlight and filter critical tasks and longest path
Critical task calculation
Longest path calculation
Using Isolate Path to analyze a schedule
Highlight and filter critical tasks and longest path
For a more hands-on experience, navigate through the player for an interactive walk-through, or if you prefer a more detailed approach, scroll down for a step-by-step guide:
Highlight Critical Tasks and Longest Path:
- On the Gantt Chart, click on Display to open the dropdown list
- Click on the respective toggle to active either Critical Tasks or Longest Path
- Once activated, ALICE will highlight respective activities in the Gantt chart with RED for critical and BLUE Hatch for the longest activities.
Filter Gantt Chart by Critical Tasks, Longest Path or Total Float:
- Click on Select to Filter to open the Filter Builder
- In the Criticality section, select Critical Tasks, Longest Path or Total Float
- ALICE allows to select multiple at the same time
- Click Done to apply the filter
Critical task calculation
By default, ALICE considers tasks as critical if they have zero or less total float. Total float is calculated by the following logic:
- Start float = late start - early start
- Finish float = late finish - early finish (default)
- Total Float is the smallest number of the two calculations above
ALICE analyzes successors, predecessors, calendars, early start, early finish, late start and late finish of each activity and calculates the free float and total float. Just like in P6, your critical tasks are updated as you make updates to your projects.
In ALICE Core this calculation is done in two places:
- On the Plan page, when the user makes edits to the plan and hits Reschedule
- On the Analyze page when the user views a solution that has been generated from a scenario
In both situations all the float calculations are done based on the precedence links and not resource links.
In ALICE Pro, this calculation is done only on the Analyze page and it also considers resource links in float calculation.
If you consider tasks with float greater than 0, you can use the filter builder to view all tasks by total float and add your desired criteria. This functionality is supported on both Gantt views in ALICE Core - Plan and Analyze. Read the filter section above to learn more.
Longest path calculation
The longest path is the sequence of tasks in a project schedule that determines the project's overall duration. It is similar to the critical path, but instead of focusing on tasks with zero float, it uses gaps between tasks (free float) to calculate the longest chain of dependent activities. It’s a good practice to identify and optimize the longest path in ALICE since it directly affects the duration of your project.
Calculation Methods:
Longest path = min(Predecessor Gap)
Calculation of free float (gaps between tasks): ALICE starts with the last task (or milestone) in the project and looks at its predecessors, considering minimum gaps between tasks.
It continues backward through the project by selecting the predecessor with the least amount of gap. This path indicates tasks that are dependent on one another and have the least amount of gap. One thing to keep in mind is that ALICE Core does not account for resource links while calculating the longest path. It only looks at hard logic(precedence links). In Pro, ALICE does account for resource links to calculate the free float.
Using Isolate Path to analyze a schedule
The isolate path feature allows users to identify all the activities that are in the path of any activity. It will look at predecessors and successors of an activity that you select and show you all the activities in the network. It will show predecessors of predecessors, same for successors.
This is very helpful if you want to optimize for specific milestones and you want to identify which activities you would like to optimize in order to optimize for that specific activity.
To isolate path, right click on any activity either on the Gantt chart or the task list and select Isolate Path.