Download the DOTPRODUCT and QUADPRODUCT Functions
Frontline Systems' DOTPRODUCT and QUADPRODUCT functions make it easier for you to set up Solver models whose objective and constraints are linear or quadratic functions of the variables. They can be used to simplify formulas in your spreadsheet -- and when they are used in conjunction with our Analytic Solver products, they can greatly speed up the process of preparing your model for solution -- what we call "fast problem setup".
DOTPRODUCT is a generalized form of SUMPRODUCT, which is standard in Microsoft Excel. SUMPRODUCT is limited to arguments that are simple selections (not multiple selections) of the same orientation ( a column or a row), and it cannot be used in array formulas. DOTPRODUCT accepts multiple selections for both arguments, and it can be used in array formulas.
QUADPRODUCT is an add-in function that allows you to compute a quadratic function in one step. A common use of QUADPRODUCT is in the construction of efficient portfolios, often called portfolio optimization, where the objective is to minimize the total portfolio variance (a measure of riskiness), subject to a threshold on the expected portfolio return.
Both of these functions are implemented by a single Excel add-in dynamic link library (a so-called XLL), which is included with the Analytic Solver products. But you can download the XLL here and use these functions with the standard Excel Solver, or even in an Excel worksheet which isn't designed for the Solver. Using these functions will help you move more easily to "fast problem setup" if and when you upgrade to one of our Premium Solver products.
Follow these steps:
- Download Dotprd32.xll if you are using Excel XP, Excel 2000, Excel 97 or Excel 95. Download Dotprod.xll only if you are still using Excel 5.0 on Windows 3.1 (but consider an upgrade!).
- Download Dotprd32.hlp in either case -- This is a Windows Help file describing installation and use of DOTPRODUCT and QUADPRODUCT.
- Copy the file Dotprd32.xll (or Dotprod.xll) to your Excel Solver subdirectory (for example, C:\Program Files\Microsoft Office\Office\Library\Solver).
- Start Excel, and choose Tools Add-Ins... to display the Add-Ins dialog.
- Click the Browse... button, navigate to the Excel Solver subdirectory, select the XLL file, and click OK.
- The Add-Ins dialog should reappear, with "Frontline's Mathematical Functions" included in the list of available add-ins. Ensure that the box next to this entry is checked, and click OK.
- You can now use DOTPRODUCT and QUADPRODUCT in your Excel formulas. You'll even find these functions included in the Function Wizard when you select Insert Function... .
