#!/bin/env python import xpress as xp p = xp.problem () # fill in a problem with three variables and four constraints p.loadproblem ("", # probname ['G','G','E', 'L'], # qrtypes [-2.4, -3, 4, 5], # rhs None, # range [3,4,5], # obj [0,2,4,8], # mstart None, # mnel [0,1,2,3,0,1,2,3], # mrwind [1,1,1,1,1,1,1,1], # dmatval [-1,-1,-1], # lb [3,5,8], # ub colnames = ['x1','x2','x3'], # column names rownames = ['row1','row2','row3','constr_04']) # row names p.write ("loadlp", "lp") p.solve () # Create another variable and add it, then modify the objective # function. Note that the objective function is replaced by, not # amended with, the new objective x = xp.var() p.addVariable (x) p.setObjective (x**2 + 2*x + 444) p.solve() p.write ("updated", "lp")