GPM, Early, and Late Dates-Modes

NetPoint is based on the Graphical Path Method (GPM®), an innovative scheduling algorithm that governs the behavior of activities and events in a network-based schedule. However, activities, and their resource histograms and curves, can also be viewed on their CPM early or late dates. This gives NetPoint the ability to schedule forward from the project start or backward from the project completion.

In GPM Planning Mode, activities can be scheduled anywhere between their early and late dates (on what are called “planned dates”) without needing to constrain them (in CPM, constrained dates reduce total float).

In CPM Early Dates Mode, all connected activities are pulled back to their traditional CPM early-start dates (activities without any predecessors will remain on their GPM planned-dates). This mode is helpful for drawing and linking activities rapidly or push-planning from the project start. Effectively, activities can be drawn on the canvas as late as desired, without needing to think about exact dates or fine-tuning their positions.

In CPM Late Dates Mode, all connected activities are pushed forward to their traditional CPM late-start dates (activities without any predecessors will remain on their GPM planned-dates). This mode is helpful for pull-planning from the project completion.

In addition to switching between modes for the entire schedule, activities can be snapped to their early or late dates on an individual basis. Instructions are provided below.

NOTE: In CPM early and late dates modes, all link gaps and drifts equal zero, and all floats equal total floats.

NOTE: Do not change from GPM to early or late modes if there are any negative gaps in the schedule or any objects beyond the project completion. Otherwise, GPM dates may no longer match.

Steps

Changing Modes

  1. Click the down arrow next to the GPM/Early Dates/Late Dates icon in the toolbar.
  2. Select the desired mode from the list.

Snapping to Predecessors/Successors

  1. With the Select Tool chosen in the toolbar, right-click on a desired activity.
  2. Choose Snap to Predecessors or Snap to Successors accordingly.

Notes

Working in Early or Late Dates Modes

It is recommended that modifications to the network always be done in GPM Planning mode. If you modify the positions of activities in early or late-dates modes, negative gaps will temporarily form until the canvas has been clicked and activities return to their calculated positions.

Additionally, when switching between modes, you may observe unexpected results. For example, when switching between early-dates and GPM modes, the later of the two dates will be kept for all activities. When switching between late-dates and GPM modes, the earlier of the two dates will be kept for all activities. In both cases, if any activity has zero total float, it will be maintained. Original dates and gaps will be restored only for those relationships that have gone unmodified. If the project start is modified, it will not revert.

Updating in Early or Late Dates Modes

During schedule updates in CPM early or late dates mode, all activities to the left of the data date (or crossing through it) must have start and finish constraints applied before a data date is placed. Otherwise, all connected activities and milestones will jump to the data date and be unable to be actualized. For instructions, see Constraining Activities and Bulk-Editing Objects.