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batchmode_cs.cs
/* Copyright 2023, Gurobi Optimization, LLC */
/* This example reads a MIP model from a file, solves it in batch mode,
and prints the JSON solution string.
You will need a Cluster Manager license for this example to work. */
using System;
using Gurobi;
class batchmode_cs
{
/// <summary>Set-up the environment for batch mode optimization.
/// </summary>
/// <remarks>
/// The function creates an empty environment, sets all neccessary
/// parameters, and returns the ready-to-be-started Env object to
/// caller.
/// </remarks>
static void setupbatchenv(ref GRBEnv env)
{
env.CSBatchMode = 1;
env.CSManager = "http://localhost:61080";
env.LogFile = "batchmode.log";
env.ServerPassword = "pass";
env.UserName = "gurobi";
// No network communication happened up to this point. This will happen
// now that we call start().
env.Start();
}
///<summary>Print batch job error information, if any</summary>
static void printbatcherrorinfo(ref GRBBatch batch)
{
if (batch.BatchErrorCode == 0)
return;
Console.WriteLine("Batch ID: " + batch.BatchID + ", Error code: " +
batch.BatchErrorCode + "(" +
batch.BatchErrorMessage + ")");
}
///<summary>Create a batch request for given problem file</summary>
static string newbatchrequest(string filename)
{
string batchID= "";
// Create an empty environment
GRBEnv env = new GRBEnv(true);
// set environment and build model
setupbatchenv(ref env);
GRBModel model = new GRBModel(env, filename);
try {
// Set some parameters
model.Set(GRB.DoubleParam.MIPGap, 0.01);
model.Set(GRB.IntParam.JSONSolDetail, 1);
// Define tags for some variables to access their values later
int count = 0;
foreach (GRBVar v in model.GetVars()) {
v.VTag = "Variable" + count;
count += 1;
if (count >= 10) break;
}
// Submit batch request
batchID = model.OptimizeBatch();
} finally {
// Dispose of model and env
model.Dispose();
env.Dispose();
}
return batchID;
}
///<summary>Wait for the final status of the batch. Initially the
/// status of a batch is <see cref="GRB.BatchStatus.SUBMITTED"/>;
/// the status will change once the batch has been processed
/// (by a compute server).</summary>
static void waitforfinalstatus(string batchID)
{
// Wait no longer than one hour
double maxwaittime = 3600;
DateTime start = DateTime.Now;
// Setup and start environment, create local Batch handle object
GRBEnv env = new GRBEnv(true);
setupbatchenv(ref env);
GRBBatch batch = new GRBBatch(env, batchID);
try {
while (batch.BatchStatus == GRB.BatchStatus.SUBMITTED) {
// Abort this batch if it is taking too long
TimeSpan interval = DateTime.Now - start;
if (interval.TotalSeconds > maxwaittime) {
batch.Abort();
break;
}
// Wait for two seconds
System.Threading.Thread.Sleep(2000);
// Update the resident attribute cache of the Batch object
// with the latest values from the cluster manager.
batch.Update();
// If the batch failed, we retry it
if (batch.BatchStatus == GRB.BatchStatus.FAILED) {
batch.Retry();
System.Threading.Thread.Sleep(2000);
batch.Update();
}
}
} finally {
// Print information about error status of the job
// that processed the batch
printbatcherrorinfo(ref batch);
batch.Dispose();
env.Dispose();
}
}
///<summary>Final Report for Batch Request</summary>
static void printfinalreport(string batchID)
{
// Setup and start environment, create local Batch handle object
GRBEnv env = new GRBEnv(true);
setupbatchenv(ref env);
GRBBatch batch = new GRBBatch(env, batchID);
switch(batch.BatchStatus) {
case GRB.BatchStatus.CREATED:
Console.WriteLine("Batch status is 'CREATED'\n");
break;
case GRB.BatchStatus.SUBMITTED:
Console.WriteLine("Batch is 'SUBMITTED\n");
break;
case GRB.BatchStatus.ABORTED:
Console.WriteLine("Batch is 'ABORTED'\n");
break;
case GRB.BatchStatus.FAILED:
Console.WriteLine("Batch is 'FAILED'\n");
break;
case GRB.BatchStatus.COMPLETED:
Console.WriteLine("Batch is 'COMPLETED'\n");
// Get JSON solution as string
Console.WriteLine("JSON solution:" + batch.GetJSONSolution());
// Write the full JSON solution string to a file
batch.WriteJSONSolution("batch-sol.json.gz");
break;
default:
// Should not happen
Console.WriteLine("Unknown BatchStatus" + batch.BatchStatus);
Environment.Exit(1);
break;
}
// Cleanup
batch.Dispose();
env.Dispose();
}
///<summary>Instruct the cluster manager to discard all data relating
/// to this BatchID</summary>
static void batchdiscard(string batchID)
{
// Setup and start environment, create local Batch handle object
GRBEnv env = new GRBEnv(true);
setupbatchenv(ref env);
GRBBatch batch = new GRBBatch(env, batchID);
// Remove batch request from manager
batch.Discard();
// Cleanup
batch.Dispose();
env.Dispose();
}
///<summary>Solve a given model using batch optimization</summary>
static void Main(string[] args)
{
if (args.Length < 1) {
Console.Out.WriteLine("Usage: batchmode_cs filename");
return;
}
try {
// Submit new batch request
string batchID = newbatchrequest(args[0]);
// Wait for final status
waitforfinalstatus(batchID);
// Report final status info
printfinalreport(batchID);
// Remove batch request from manager
batchdiscard(batchID);
Console.WriteLine("Batch optimization OK");
} catch (GRBException e) {
Console.WriteLine("Error code: " + e.ErrorCode + ". " +
e.Message);
}
}
}
