Getting started with LP Solver is relatively straightforward if you’re familiar with a typical Excel spreadsheet. You see the ingredient matrix on the main window. The columns are the cost of each ingredient, a minimum and maximum that defines the inclusion rates for each ingredient and then nutrients, dry matter, protein, fat ash, etcetera.
The rows within the matrix are the ingredients, and here we see the ingredients for a typical calf starter including barley, corn, soybean meal, oat, grain, etcetera. The last two rows are the minimum and maximums for each of the nutrients. For example, in the dry matter column we see the minimum should be 85% and the maximum should be 95%.
LP Solve includes a number of example files that are downloaded when you install the program. Therein your documents LPSolve V1.0 folder.
You can change the number of ingredients in a formula using the box above the matrix, and you can also look at the number of nutrients available within the matrix. There are as many as 53 nutrients you can view.
The nutrient columns can be reordered and when you include a minimum or maximum then the column title color will change from Gray to blue. Blue indicates that the column cannot be hidden since they contain a minimum or a maximum. The Gray columns without a min or Max can be hidden simply by clicking on the column header, and that will cause the column to be hidden from view. If we right-click on any column headers, a new box will open that allows us to select one of the currently hidden columns or nutrients. This allows you to see the columns that might be important to you.
The bottom left contains some the metadata associated with the file, including the name of the file, the farm, the formula, the author, and a brief description, as well as when the file was first created.
Once you’ve entered the prices, the min and Max for each of the ingredients and the nutrients, click the Run button. This will initiate the linear programming engine. If a feasible solution is found, a new window will open that shows the ingredient matrix along with additional information including the cost of the formula. As well as the percentages of each ingredient that are included in the final formula, there’s also sensitivity analysis information included in the results.
You can change the nutrient composition of or of any or all of the ingredients, change ingredients included in the matrix – add, delete, or reorder ingredients within the formula. The knowledge base contains more information about using the ingredients and nutrient ingredients and ingredient library, as well as the nutrient content within the program.
