# Local Trend Graph PropertyManager

With the Local Trend Graph PropertyManager, you can gain insight into the relation between an objective or constraint (dependent variables) and specific design variables (independent variables).

To display the Local Trend Graph PropertyManager:

From the left frame of a Design Study tab, right-click Results and Graphs , and click Define Local Trend Graph.

The table summarizes the availability of the Local Trend Graph for Optimization and Design Studies.
Types of Variables Optimization Studies Design Studies
• Continuous variables within range
• Results quality = High quality
Local Trend Graph is available NA
• Continuous variables within range
• Results quality = Fast results
Local Trend Graph is available NA
• Discrete Variables
• Results quality = High quality
NA NA
• Discrete Variables
• Results quality = Fast Results
Local Trend Graph is available Local Trend Graph is available
• Combination of Discrete and Continuous Variables within range
• Results quality = High quality
Local Trend Graph is available NA
• Combination of Discrete and Continuous Variables within range
• Results quality = Fast Results
Local Trend Graph is available NA

A local trend graph provides an insight as to the change in value of an objective or constraint (dependent variable) within a permissible range of the independent design variables.

The independent value of the design variable is plotted for the selected iteration. The graph shows the trend of the dependent variable (objective or goal) as the independent variable varies within the permissible range.

An ascending concave curve would indicate that for the values in the neighborhood of the selected variable, the value of a constraint or objective is increasing, and the rate of change is also increasing. This could indicate a strong correlation between the design variable and the constraint or objective. A descending concave graph would indicate a downward trend, while also giving insight as to the strength of any correlation. A flat horizontal line may indicate that there is no correlation between a change in the variable value and the constraint or objective values.

The local trend graph does not show the values of the dependent design variable at each iteration.

## Design Variables (X-Axis)

Select one design variable to plot along the X-axis. The range of values are dependent on the selected iteration.

## Y-Axis

 Objective Select the design objective (or goal) to plot on the Y-axis. Constraint Select one constraint to plot on the Y-axis. Normalized to initial value Plots the ratio of the objective or constraint variable value to its initial value from the initial scenario. Local trend at The permissible range of values for the design variable is dependent on the selected iteration.