Abstract
LP (linear programming) and other programming techniques can be used to make a farm crop production plan or to estimate the impact of a new agricultural technology. XLP is a computer program running on Excel in Microsoft Windows to compute the optimal solution of a LP. XLP can provide an optimal solution for a LP model. It can solve a GP (goal programming) model, which can incorporate multiple objectives such as average income and reduced working time. It can also solve IP (integer programming) models, which can incorporate productive elements counted by discrete units, such as domestic animals, green houses, or fixed costs. The interface program of XLP is coded in VBA (Visual Basic for Applications). The computational engine for LPs (LP, GP and IP) is coded in Delphi. XLP is easy to use. The LP model is entered on an Excel worksheet “tableau” in a particular format. An additional XLP menu of computational options is added to the Excel menu bar at startup. The optimal solution is shown on worksheet as a “computed result”. XLP is directly used as a tool to describe an LP model and to solve it. It is also used as a computing engine in developing an Excel workbook-based application which builds a farming model automatically from collected data on farming and helps agricultural extension advisors and farmers use LP models. We have begun to develop a program like the above-mentioned application too. XLP can be downloaded from the following URLs: http://39you.net/xlp/ or http://cse.naro.affrc.go.jp/ooisi/
