A Two-Way Rainbow Diagram is an in-depth look at the effects of varying two variables on the optimal policy and expected value (and or certain equivalent if applicable). Two-Way Rainbows can only be run for values initialized with a constant expression.
Analyzing Two-Way Rainbow Diagrams
When the sensitivity runs are complete, DPL opens a Two-Way Rainbow Diagram window and displays a graph with the range of values for the first sensitivity variable along the horizontal axis and the range of values for the second sensitivity variable along the vertical axis. A region in which the optimal policy is the same is indicated with a single color. If there is more than one colored region in the graph, the optimal policy is different depending on the value of the sensitivity variables. Because model outputs are determined at discrete values over a range of the sensitivity variables, you should not assume that the line between regions indicates the precise value at which the policy changes. If the precise point at which the policy changes is important, rerun the sensitivity analysis using a narrower range and smaller increments.
If you receive a message that reads, "Too many decision policies. Some colors will represent more than one policy," then there are more than 224 decision policies in the diagram. In this case, you may wish to compare the expected value and policy information at each of the intersection points in the Two-Way Rainbow Diagram using Show Tips or look at the Session Log for more information.
Policy Information
If Show Tips is turned on within View | Tips, you will be able to view the expected value and policy information by placing the mouse cursor over the markers displayed on the diagram. This information is also printed to the Session Log.
NOTE: If your model has a Halt function in the Objective Function or the Constraint Function, the Two-Way Rainbow Diagram will not display policy changes. (See Constraint Functions)
Versions: DPL Professional, DPL Enterprise, DPL Portfolio
See Also