This type of problem is usually handed by employing a standardized file format tailored to the problem at hand. For linear programming problems, the old, commonly-used format is MPS:
http://en.wikipedia.org/wiki/MPS_(format) I don't know if there is a format which might be better/newer (if any) since I don't pretend to be an expert in this area. Nonetheless, I think your best bet would be to find your preferred file format for LP problems and write an importer for it (or find one which somebody has already created). Don't try to write a parser for your own format since it's a pain to do, and the problem has already been solved a number of times. Best of luck, Stuart On Tue, 18 Nov 2014, Bodo Kaiser wrote:
In university we have a course where we have a course where you define a "linear program" to find out which product or product-combination is best to product to have maximum revenue. The basic approach is to define a target equation: z = 4x + 3y x := amount of product 1 y := amount of product 2 which we maximize under some side conditions: 1. 5x + 10y ? 100 2. x ? 20 The first case could mean that we have 100h of working hours as capacity where it takes 5h to produce product 1 and 10h to produce product 2. The second case could mean that we have to supply the market with a minimum amount of 20 units of product 1. You can put this into a matrix: A = [5 10 1 0 100; 1 0 0 1 20; 4 3 0 0 -1] and apply the "Simplex" algorithm to find the value of x and y where z reaches maximum without breaking side conditions. To cut a long story short to apply the simplex algorithm we need to transform all conditions into a "canonical form" (e.g. convert greater then to less then). If I now would like to write a julia script which does solve linear programs for me I need to "read" the equation and change it. Do I need to write some sort of string based equation parser or is there some package which would do this for me? Best, Bo
