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Lpmethod.java
/* Copyright 2020, 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());
}
}
}
