Working with PTC Mathcad Prime > Working with Math Expressions > Evaluating Math Expressions > About Controlling Region Calculation
  
About Controlling Region Calculation
By default the numerical results and graphs in your worksheet update automatically. However, some equations take a long time to calculate. They may contain repeated evaluations, or an algorithm may take a long time to converge. If you do not want to wait for computations to complete, you can stop region calculation in one of two ways:
Stop all region calculations
Stop calculations in select regions
Stop All Region Calculations
If you edit a region then that region and all dependent regions are dimmed and the results are not recalculated.
The green dot in the left-hand side of the status bar turns red.
Stop Calculations in Select Regions
Disabled regions are immediately dimmed, as shown below:
Enabled Region
Disabled Region
You can edit a disabled region but the changes that you make do not affect calculations in subsequent regions
The state of Auto Calculation does not affect disabled regions
Regions that are dependent on definitions or calculation results from disabled regions report errors
The green dot in the left-hand side of the status bar remains green as long as Auto Calculation is enabled
Additional Information
When you open a worksheet, PTC Mathcad Prime does not recalculate results automatically even if Auto Calculation is enabled. You must click Calculate or press Ctrl+F5 to recalculate the worksheet and view the final results. The recalculation is important when you are dealing with legacy PTC Mathcad worksheets that you converted or with files that contain included worksheets.