Lpmethod.java

/* Copyright 2021, Gurobi Optimization, LLC */ /* Solve a model with different values of the Method parameter; show which value gives the shortest solve time. */ import gurobi.*; public class Lpmethod { public static void main(String[] args) { if (args.length < 1) { System.out.println("Usage: java Lpmethod filename"); System.exit(1); } try { // Read model GRBEnv env = new GRBEnv(); GRBModel model = new GRBModel(env, args[0]); // Solve the model with different values of Method int bestMethod = -1; double bestTime = model.get(GRB.DoubleParam.TimeLimit); for (int i = 0; i <= 2; ++i) { model.reset(); model.set(GRB.IntParam.Method, i); model.optimize(); if (model.get(GRB.IntAttr.Status) == GRB.Status.OPTIMAL) { bestTime = model.get(GRB.DoubleAttr.Runtime); bestMethod = i; // Reduce the TimeLimit parameter to save time // with other methods model.set(GRB.DoubleParam.TimeLimit, bestTime); } } // Report which method was fastest if (bestMethod == -1) { System.out.println("Unable to solve this model"); } else { System.out.println("Solved in " + bestTime + " seconds with Method: " + bestMethod); } // Dispose of model and environment model.dispose(); env.dispose(); } catch (GRBException e) { System.out.println("Error code: " + e.getErrorCode() + ". " + e.getMessage()); } } }