OR-Tools Java MemoryLeakSolver

MemoryLeakSolver.java

// Copyright 2010-2018 Google LLC
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.ortools;

import com.google.ortools.Loader;
import com.google.ortools.sat.CpSolverStatus;
import com.google.ortools.sat.IntervalVar;
import com.google.ortools.sat.CpModel;
import com.google.ortools.sat.CpSolver;
import com.google.ortools.sat.IntVar;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.IntStream;
import java.util.Random;
import java.util.logging.Logger;

/** Memory Leak Solver Samples */
public class MemoryLeakSolver {
  private static final Logger logger = Logger.getLogger(MemoryLeakSolver.class.getName());

  public static final int NUM_OBSERVATIONS =  6000;
  public static final int NUM_NIGHTS       =  180;
  public static final int SLOTS_PER_NIGHT  =  10;
  public static final int SLOTS_PER_DAY    =  24;
  public static final int TOTAL_SLOTS      =  NUM_NIGHTS * SLOTS_PER_DAY;

  public static long getMaxMemory() {
    return Runtime.getRuntime().maxMemory();
  }

  public static long getUsedMemory() {
    return getMaxMemory() - getFreeMemory();
  }

  public static long getTotalMemory() {
    return Runtime.getRuntime().totalMemory();
  }

  public static long getFreeMemory() {
    return Runtime.getRuntime().freeMemory();
  }

  public static boolean schedule(List<Integer> obs) {
    // create constraint model
    CpModel model = new CpModel();

    List<IntervalVar> intervals = new LinkedList<IntervalVar>();
    for (int i = 0; i < obs.size(); i++) {
      // constraint: observation intervals with their duration
      IntVar from = model.newIntVar(0, TOTAL_SLOTS - 1, "OB from " + i);
      IntVar to   = model.newIntVar(0,  TOTAL_SLOTS - 1, "OB to " + i);
      intervals.add(model.newIntervalVar(from, obs.get(i), to, "OB Interval " + i));
    };
    // constraint: exclude daytime slots 10 ... 23
    IntStream.range(0, NUM_NIGHTS).forEach(night -> {
      intervals.add(model.newFixedInterval(night * SLOTS_PER_DAY + SLOTS_PER_NIGHT, SLOTS_PER_DAY - SLOTS_PER_NIGHT,
            "Reserved day daytime " + night));
    });
    // constraint: no slot overlap
    model.addNoOverlap(intervals.toArray(new IntervalVar[0]));

    CpSolverStatus status = new CpSolver().solve(model);
    return status == CpSolverStatus.OPTIMAL || status == CpSolverStatus.FEASIBLE;
  }

  public static void main(String[] args) throws Exception {
    Loader.loadNativeLibraries();
    // prepare observations with variable duration 1 .. 10
    Random rand = new Random();
    Integer[] observations = new Integer[NUM_OBSERVATIONS];
    IntStream.range(0, observations.length).forEach(i -> {
      observations[i] = 1 + rand.nextInt(3);
    });

    LinkedList<Integer> scheduledObservations = new LinkedList<Integer>();
    System.out.println("Total observations to schedule: " + observations.length);
    IntStream.range(0, observations.length).forEach(i -> {
      System.out.println("KB: " + getUsedMemory() / 1024);
      scheduledObservations.add(observations[i]);
      if (schedule(scheduledObservations)) {
        System.out.println("Scheduled observation " + (i + 1));
      } else {
        scheduledObservations.removeLast();
        System.out.println("Skipping observation " + (i + 1));
      }
    });
    System.out.println("Done. Scheduled " + scheduledObservations.size() + " observations");
  }
}

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project
  xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>

<groupId>com.google.ortools</groupId>
<artifactId>MemoryLeakSolver</artifactId>
<version>1.0.0</version>
<packaging>jar</packaging>

<name>${project.groupId}:${project.artifactId}</name>
<description>Google OR-Tools Java project.</description>
<url>https://github.com/google/or-tools</url>

<licenses>
  <license>
    <name>The Apache License, Version 2.0</name>
    <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
  </license>
</licenses>

<developers>
  <developer>
    <name>Corentin "Mizux" Le Molgat</name>
    <email>[email protected]</email>
    <organization>Google LLC</organization>
    <organizationUrl>http://www.google.com</organizationUrl>
  </developer>
  <developer>
    <name>Laurent Perron</name>
    <email>[email protected]</email>
    <organization>Google LLC</organization>
    <organizationUrl>http://www.google.com</organizationUrl>
  </developer>
</developers>

<scm>
  <connection>scm:git:git://github.com/google/or-tools.git</connection>
  <developerConnection>scm:git:ssh://github.com:google/or-tools.git</developerConnection>
  <url>http://github.com/google/or-tools/tree/master</url>
  <tag>HEAD</tag>
</scm>

<issueManagement>
  <system>GitHub Issues</system>
  <url>http://github.com/google/or-tools/issues</url>
</issueManagement>

<properties>
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  <exec.mainClass>com.google.ortools.MemoryLeakSolver</exec.mainClass>
  <maven.compiler.source>1.8</maven.compiler.source>
  <maven.compiler.target>1.8</maven.compiler.target>
</properties>

<dependencies>
  <dependency>
    <groupId>com.google.ortools</groupId>
    <artifactId>ortools-java</artifactId>
    <version>[8.0,)</version>
    <type>jar</type>
    <scope>compile</scope>
  </dependency>
</dependencies>

<build>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-source-plugin</artifactId>
      <version>3.2.0</version>
      <executions>
        <execution>
          <id>attach-sources</id>
          <goals>
            <goal>jar-no-fork</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-javadoc-plugin</artifactId>
      <version>3.2.0</version>
      <executions>
        <execution>
          <id>attach-javadocs</id>
          <goals>
            <goal>jar</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>
</project>