Frontline's Add-in Functions for Microsoft Excel

Included with the Premium Solver and Large-Scale LP Solver for Microsoft Excel is an add-in Dynamic Link Library (XLL) which provides two new functions for use in Excel spreadsheets: DOTPRODUCT and QUADPRODUCT. This page (and its hyperlinks, which provide detailed information) will show how you can use these functions to simplify your Solver models and make them more efficient -- especially when used with our enhanced solvers.

If you sign up (it's free) for our Private Web for Solver Users, you can download the XLL and use these functions in any of your own Excel spreadsheets -- even if you don't have one of our enhanced solvers!

DOTPRODUCT Function

DOTPRODUCT is a generalized form of SUMPRODUCT, which is standard in Microsoft Excel. SUMPRODUCT is limited to arguments which 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 Function

QUADPRODUCT is an add-in function which 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.

Fast Problem Setup

Frontline's Premium Solver and Large-Scale LP Solver for Microsoft Excel include a feature called fast problem setup. This feature can greatly speed up the process of preparing your model for optimization -- the time spent in Microsoft Excel with "Setting up Problem..." on the message bar. On large models, fast problem setup can be up to 100 times faster! DOTPRODUCT and QUADPRODUCT, along with several standard Microsoft Excel functions such as SUM and SUMPRODUCT, are recognized by the fast problem setup process. And the array form of DOTPRODUCT is even more efficient than individual uses of this function, both for general recalculation and for fast problem setup.

Copyright © 1996 Frontline Systems Inc.
Last modified: January 19, 1997