# Multi Calc Dialog

This allows you to run multiple calculations, changing the value of a single property for one or more elements in each iteration, and saving the accumulated results to a spreadsheet. To display the Multi Calc Dialog: ▪Select the Tools | Multi Calc menu item. Toolbar Buttons •Use the toolbar buttons to create a new FMC (FluidFlow Multi Calc) file; open an existing one; save the current FMC you're working on to a new file name; or import/export individual multi calc records between FMC files. NOTE: The changes you make to your current FMC are saved automatically when you close the dialog, i.e., you are not prompted to save changes, they are saved automatically. •The '+', '-', and 'Copy' buttons allow you to add a new multi calc, delete the currently selected one, or to make a copy of the currently selected record. •You can use the 'Properties' button to specify what properties should be available in the Property to Change drop-down. •The 'Run' button will execute the currently selected multi calc, updating the status bar at the bottom of the dialog on the progress. (Note: Some models may take some time to complete if there are a large number of runs to perform.) How it Works The type of property value change between "multi calc" iterations can be one of four types of Input Source: Step-wise This allows you to specify Starting and Ending values, and the number of Steps between these values to take. For example, specifying 1 and 10 for the Start/End values for Elevation, and the number of Steps as 10, means that the calculations will run 10 times, starting at 1, then 2, then 3, etc., up until 10. Incremental This is a variation on Step-wise in that you specify the amount to change a property by, from a start value until the end value is reached. Note, you can use this to decrease the value as shown below: In this example, the Temperature of the selected element is specified to start at 45, and will be decremented by 5 until it reaches 15. This will result in 7 calculation runs where the temperature will be 45, 40, 35, 30, 25, 20, and 15. User-entered In this mode, you can specify the different values to set a property to from a list you populate. You can also specify that the multi calc applies to an element (or elements), as opposed to the currently selected element(s) on your flowsheet. For example in the image below, we are applying a range of values - 140, 150, 160, and 170 - as 4 separate calculations to Node 4 (a centrifugal pump). Note: When you select 'Specify Element(s)' from Apply To, the list of available elements will be filtered based on what is relevant to the Property to Change field value. For example, in the above, Impeller Diameter is only available for the Pump in the flowsheet, so none of the other nodes/pipes are displayed. Excel Linked Here you can specify an Excel file, open it (in the dialog), and select a range of cells that you want to use as the source for your property values. In the above example we are changing the Operating Speed value of Pump 4 to the values from cells B3 to B7 in the Pump Speed Data.xlsx file. This will run 5 times for 1450, 1550, 2000, 3000, and 3500. Note: The advantage of this approach over the 'User-entered' is that you can change the values in the underlying spreadsheet and Multi Calc will read from them at runtime. Report Results After running the multi calc, you can review the results in the 'Report' tab, as per the image below. The results can be filtered by all available, or on an individual run-basis. Use the toolbar buttons to save the results to an Excel (XLSX) file, or to preview the report in Excel (or the FF3 Previewer.) Additionally, the 'Messages' sheet will contain hints/warnings/errors encountered during each calculation run.