Batchmode.java
/* Copyright 2021, Gurobi Optimization, LLC */
/* This example reads a model from a file, solves it in batch mode
* and prints the JSON solution string. */
import gurobi.*;
public class Batchmode {
// Set-up a batch-mode environment
private static GRBEnv setupbatchconnection() throws GRBException {
GRBEnv env = new GRBEnv(true);
env.set(GRB.IntParam.CSBatchMode, 1);
env.set(GRB.StringParam.LogFile, "batchmode.log");
env.set(GRB.StringParam.CSManager, "http://localhost:61080");
env.set(GRB.StringParam.UserName, "gurobi");
env.set(GRB.StringParam.ServerPassword, "pass");
env.start();
return env;
}
// Display batch-error if any
private static void batcherrorinfo(GRBBatch batch) throws GRBException {
// Get last error code
int error = batch.get(GRB.IntAttr.BatchErrorCode);
if (error == 0) return;
// Query last error message
String errMsg = batch.get(GRB.StringAttr.BatchErrorMessage);
// Query batchID
String batchID = batch.get(GRB.StringAttr.BatchID);
System.out.println("Batch ID " + batchID + "Error Code " +
error + "(" + errMsg + ")");
}
// Create a batch request from the given problem file
private static String newbatchrequest(String filename) throws GRBException {
// Setup a batch connection
GRBEnv env = setupbatchconnection();
// Read a model
GRBModel model = new GRBModel(env, filename);
// Set some parameters
model.set(GRB.DoubleParam.MIPGap, 0.01);
model.set(GRB.IntParam.JSONSolDetail, 1);
// Set-up some tags, we need tags to be able to query results
int count = 0;
for (GRBVar v: model.getVars()) {
v.set(GRB.StringAttr.VTag, "UniqueVariableIdentifier" + count);
count += 1;
if (count >= 10) break;
}
// Batch-mode optimization
String batchid = model.optimizeBatch();
// no need to keep the model around
model.dispose();
// no need to keep environment
env.dispose();
return batchid;
}
// Wait for final status
private static void waitforfinalstatus(String batchid) throws Exception {
// Setup a batch connection
GRBEnv env = setupbatchconnection();
// Create Batch-object
GRBBatch batch = new GRBBatch(env, batchid);
try {
// Query status, and wait for completed
int status = batch.get(GRB.IntAttr.BatchStatus);
long timestart = System.currentTimeMillis();
while(status == GRB.BatchStatus.SUBMITTED) {
// Abort if taking too long
long curtime = System.currentTimeMillis();
if (curtime - timestart > 3600 * 1000) {
// Request to abort the batch
batch.abort();
break;
}
// Do not bombard the server
Thread.sleep(2000);
// Update local attributes
batch.update();
// Query current status
status = batch.get(GRB.IntAttr.BatchStatus);
// Deal with failed status
if (status == GRB.BatchStatus.FAILED ||
status == GRB.BatchStatus.ABORTED ) {
// Retry the batch job
batch.retry();
}
}
} catch (Exception e) {
// Display batch-error if any
batcherrorinfo(batch);
throw e;
} finally {
// Dispose resources
batch.dispose();
env.dispose();
}
}
// Final report on batch request
private static void finalreport(String batchid) throws GRBException {
// Setup a batch connection
GRBEnv env = setupbatchconnection();
// Create batch object
GRBBatch batch = new GRBBatch(env, batchid);
try {
int status = batch.get(GRB.IntAttr.BatchStatus);
// Display depending on batch status
switch(status) {
case GRB.BatchStatus.CREATED:
System.out.println("Batch is 'CREATED'");
System.out.println("maybe batch-creation process was killed?");
break;
case GRB.BatchStatus.SUBMITTED:
System.out.println("Batch is 'SUBMITTED'");
System.out.println("Some other user re-submitted this Batch object?");
break;
case GRB.BatchStatus.ABORTED:
System.out.println("Batch is 'ABORTED'");
break;
case GRB.BatchStatus.FAILED:
System.out.println("Batch is 'FAILED'");
break;
case GRB.BatchStatus.COMPLETED:
// print JSON solution into string
System.out.println("JSON solution:" + batch.getJSONSolution());
// save solution into a file
batch.writeJSONSolution("batch-sol.json.gz");
break;
default:
System.out.println("This should not happen, probably points to a user-memory corruption problem");
System.exit(1);
break;
}
} catch (GRBException e) {
// Display batch-error if any
batcherrorinfo(batch);
throw e;
} finally {
// Dispose resources
batch.dispose();
env.dispose();
}
}
// Discard batch data from the Cluster Manager
private static void discardbatch(String batchid) throws GRBException {
// Setup a batch connection
GRBEnv env = setupbatchconnection();
// Create batch object
GRBBatch batch = new GRBBatch(env, batchid);
try {
// Request to erase input and output data related to this batch
batch.discard();
} catch (GRBException e) {
// Display batch-error if any
batcherrorinfo(batch);
throw e;
} finally {
// Dispose resources
batch.dispose();
env.dispose();
}
}
// Main public function
public static void main(String[] args) {
// Ensure enough parameters
if (args.length < 1) {
System.out.println("Usage: java Batch filename");
System.exit(1);
}
try {
// Create a new batch request
String batchid = newbatchrequest(args[0]);
// Wait for final status
waitforfinalstatus(batchid);
// Query final status, and if completed, print JSON solution
finalreport(batchid);
// once the user is done, discard all remote information
discardbatch(batchid);
// Signal success
System.out.println("OK");
} catch (GRBException e) {
System.out.println("Error code: " + e.getErrorCode() + ". "
+ e.getMessage());
} catch (Exception e) {
System.out.println("Error");
}
}
}
