code: package zemberek.lm.compression;
  
  import com.google.common.base.Stopwatch;
  import com.google.common.io.Files;
  import com.google.common.io.Resources;
  import java.io.File;
  import java.io.IOException;
  import java.net.URL;
  import java.util.Arrays;
  import java.util.Iterator;
  import java.util.concurrent.TimeUnit;
  import org.junit.Assert;
  import org.junit.Ignore;
  import org.junit.Test;
  import zemberek.core.SpaceTabTokenizer;
  import zemberek.core.io.LineIterator;
  import zemberek.core.io.SimpleTextReader;
  import zemberek.core.logging.Log;
  import zemberek.lm.BaseLanguageModel;
  import zemberek.lm.FakeLm;
  import zemberek.lm.LmVocabulary;
  import zemberek.lm.backoff.SimpleBackoffNgramModel;
  
  public class SmoothLmTest {
  
    URL TINY_ARPA_URL = Resources.getResource("tiny.arpa");
  
    @Test
    public void testGeneration() throws IOException {
      SmoothLm lm = getTinyLm();
      Assert.assertEquals(3, lm.getOrder());
    }
  
    private SmoothLm getTinyLm() throws IOException {
      return SmoothLm.builder(getTinyLmFile()).build();
    }
  
    File getTinyArpaFile() throws IOException {
      File tmp = File.createTempFile("tiny", ".arpa");
      Log.info("Temporary test Arpa model file %s", tmp);
      Files.copy(new File(TINY_ARPA_URL.getFile()), tmp);
      return tmp;
    }
  
    private File getTinyLmFile() throws IOException {
      File tmp = Files.createTempDir();
      tmp.deleteOnExit();
      final File lmFile = new File(tmp, "tiny.slm");
      Log.info("Temporary test compressed model file %s", lmFile);
      if (!lmFile.exists()) {
        UncompressedToSmoothLmConverter converter = new UncompressedToSmoothLmConverter(lmFile, tmp);
        converter.convertSmall(
            MultiFileUncompressedLm.generate(getTinyArpaFile(), tmp, "utf-8", 4).getLmDir(),
            new UncompressedToSmoothLmConverter.NgramDataBlock(16, 16, 16));
      }
      return lmFile;
    }
  
    @Test
    public void testNgramKeyExactMatch() throws IOException {
      File lmDir = Files.createTempDir();
      lmDir.deleteOnExit();
      MultiFileUncompressedLm.generate(getTinyArpaFile(), lmDir, "utf-8", 4).getLmDir();
      final File lmFile = new File(lmDir, "tiny.slm");
      UncompressedToSmoothLmConverter converter = new UncompressedToSmoothLmConverter(lmFile, lmDir);
      converter.convertSmall(
          lmDir,
          new UncompressedToSmoothLmConverter.NgramDataBlock(16, 16, 16));
      SmoothLm slm = SmoothLm.builder(lmFile).ngramKeyFilesDirectory(lmDir).build();
      SimpleBackoffNgramModel model = SimpleBackoffNgramModel.fromArpa(getTinyArpaFile());
      Iterator<SimpleBackoffNgramModel.NgramData> it = model.getAllIndexes();
      while (it.hasNext()) {
        Assert.assertTrue(slm.ngramExists(it.next().getIndexes()));
      }
    }
  
    @Test
    @Ignore("Requires external data")
    public void testBigFakeLm() throws IOException {
      int order = 4;
      final File lmFile = new File("/media/ahmetaa/depo/data/lm/fake/fake.slm");
      if (!lmFile.exists()) {
        final File arpaFile = new File("/media/ahmetaa/depo/data/lm/fake/fake.arpa");
        File tmp = new File("/tmp");
        if (!arpaFile.exists()) {
          FakeLm fakeLm = new FakeLm(order);
          fakeLm.generateArpa(arpaFile);
        }
        UncompressedToSmoothLmConverter converter = new UncompressedToSmoothLmConverter(lmFile, tmp);
        converter.convertSmall(
            MultiFileUncompressedLm.generate(arpaFile, tmp, "utf-8", 4).dir,
            new UncompressedToSmoothLmConverter.NgramDataBlock(24, 24, 24));
      }
      SmoothLm lm = SmoothLm.builder(lmFile).build();
  
      FakeLm fakeLm = new FakeLm(order);
      for (int i = 1; i <= fakeLm.order; i++) {
        FakeLm.FakeGram[] probs = fakeLm.getNgramProbs(i);
        for (FakeLm.FakeGram prob : probs) {
          Assert.assertEquals("ouch:" + Arrays.toString(prob.vals), prob.prob,
              lm.getProbability(prob.indexes), 0.001);
        }
      }
    }
  
    @Test
    public void testVocabulary() throws IOException {
      SmoothLm lm = getTinyLm();
      LmVocabulary vocab = lm.getVocabulary();
      Assert.assertTrue(vocab.contains("Ahmet"));
      int i1 = vocab.indexOf("Ahmet");
      Assert.assertTrue(vocab.contains("elma"));
      int i2 = vocab.indexOf("elma");
      Assert.assertTrue(i1 != i2);
      Assert.assertEquals("Ahmet", vocab.getWord(i1));
      Assert.assertEquals("elma", vocab.getWord(i2));
    }
  
    @Test
    public void testProbabilities() throws IOException {
      SmoothLm lm = getTinyLm();
      System.out.println(lm.info());
      LmVocabulary vocabulary = lm.getVocabulary();
      int[] is = {vocabulary.indexOf("<s>")};
      Assert.assertEquals(-1.716003, lm.getProbabilityValue(is), 0.0001);
      Assert.assertEquals(-1.716003, lm.getProbability(is), 0.0001);
      //<s> kedi
      int[] is2 = {vocabulary.indexOf("<s>"), vocabulary.indexOf("kedi")};
      Assert.assertEquals(-0.796249, lm.getProbabilityValue(is2), 0.0001);
      Assert.assertEquals(-0.796249, lm.getProbability(is2), 0.0001);
      //Ahmet dondurma yedi
      int[] is3 = {vocabulary.indexOf("Ahmet"), vocabulary.indexOf("dondurma"),
          vocabulary.indexOf("yedi")};
      Assert.assertEquals(-0.602060, lm.getProbabilityValue(is3), 0.0001);
      Assert.assertEquals(-0.602060, lm.getProbability(is3), 0.0001);
    }
  
    @Test
    public void testBackoffcount() throws IOException {
      SmoothLm lm = getTinyLm();
      LmVocabulary vocabulary = lm.getVocabulary();
      int[] is = {vocabulary.indexOf("<s>")};
      Assert.assertEquals(0, lm.getBackoffCount(is));
      int[] is2 = vocabulary.toIndexes("<s>", "kedi");
      Assert.assertEquals(0, lm.getBackoffCount(is2));
      int[] is3 = vocabulary.toIndexes("Ahmet", "dondurma", "yedi");
      Assert.assertEquals(0, lm.getBackoffCount(is3));
      int[] is4 = vocabulary.toIndexes("Ahmet", "yemez");
      Assert.assertEquals(1, lm.getBackoffCount(is4));
      int[] is5 = vocabulary.toIndexes("Ahmet", "yemez", "kırmızı");
      Assert.assertEquals(2, lm.getBackoffCount(is5));
    }
  
    @Test
    public void testExplain() throws IOException {
      SmoothLm lm = getTinyLm();
      LmVocabulary vocabulary = lm.getVocabulary();
      int[] is = {vocabulary.indexOf("<s>")};
      System.out.println(lm.explain(is));
      //<s> kedi
      int[] is2 = vocabulary.toIndexes("<s>", "kedi");
      System.out.println(lm.explain(is2));
      //Ahmet dondurma yedi
      int[] is3 = vocabulary.toIndexes("Ahmet", "dondurma", "yedi");
      System.out.println(lm.explain(is3));
      int[] is4 = vocabulary.toIndexes("Ahmet", "yemez");
      System.out.println(lm.explain(is4));
      int[] is5 = vocabulary.toIndexes("Ahmet", "yemez", "kırmızı");
      System.out.println(lm.explain(is5));
    }
  
    @Test
    public void testLogBaseChange() throws IOException {
      SmoothLm lm10 = getTinyLm();
      System.out.println(lm10.info());
      File lmFile = getTinyLmFile();
      SmoothLm lm = SmoothLm.builder(lmFile).logBase(Math.E).build();
      System.out.println(lm.info());
      Assert.assertEquals(lm.getLogBase(), Math.E, 0.00001);
      LmVocabulary vocabulary = lm.getVocabulary();
      int[] is = {vocabulary.indexOf("<s>")};
      Assert.assertEquals(l(-1.716003), lm.getProbabilityValue(is), 0.0001);
      Assert.assertEquals(l(-1.716003), lm.getProbability(is), 0.0001);
      //<s> kedi
      int[] is2 = {vocabulary.indexOf("<s>"), vocabulary.indexOf("kedi")};
      Assert.assertEquals(l(-0.796249), lm.getProbabilityValue(is2), 0.0001);
      Assert.assertEquals(l(-0.796249), lm.getProbability(is2), 0.0001);
      //Ahmet dondurma yedi
      int[] is3 = {vocabulary.indexOf("Ahmet"), vocabulary.indexOf("dondurma"),
          vocabulary.indexOf("yedi")};
      Assert.assertEquals(l(-0.602060), lm.getProbabilityValue(is3), 0.0001);
      Assert.assertEquals(l(-0.602060), lm.getProbability(is3), 0.0001);
      java.nio.file.Files.delete(lmFile.toPath());
    }
  
    private double l(double i) {
      return Math.log(Math.pow(10, i));
    }
  
    @Test
    @Ignore
    public void testActualData() throws IOException {
      Stopwatch sw = Stopwatch.createStarted();
      File lmFile = new File("/home/ahmetaa/data/lm/smoothnlp-test/lm1.slm");
      File tmp = new File("/tmp");
      if (!lmFile.exists()) {
        final File arpaFile = new File("/home/ahmetaa/data/lm/smoothnlp-test/lm1.arpa");
        UncompressedToSmoothLmConverter converter = new UncompressedToSmoothLmConverter(lmFile, tmp);
        converter.convertLarge(
            MultiFileUncompressedLm.generate(arpaFile, tmp, "utf-8", 4).dir,
            new UncompressedToSmoothLmConverter.NgramDataBlock(2, 1, 1), 20);
      }
      SmoothLm lm = SmoothLm.builder(lmFile).build();
      System.out.println(sw.elapsed(TimeUnit.MILLISECONDS));
      sw.reset();
      final int order = 3;
      final int gramCount = 1000000;
      int[][] ids = new int[gramCount][order];
      long[] trigrams = new long[gramCount];
      LineIterator li = SimpleTextReader.trimmingUTF8LineIterator(
          new File("/home/ahmetaa/data/lm/smoothnlp-test/corpus-lowercase_1000000_2000000"));
      SpaceTabTokenizer tokenizer = new SpaceTabTokenizer();
      int i = 0;
      while (i < gramCount) {
        String line = li.next();
        String[] tokens = tokenizer.split(line);
        if (tokens.length < order) {
          continue;
        }
        for (int j = 0; j < tokens.length - order - 1; j++) {
          String[] words = new String[order];
          System.arraycopy(tokens, j, words, 0, order);
          int[] indexes = lm.getVocabulary().toIndexes(words);
          if (!lm.getVocabulary().containsAll(indexes)) {
            continue;
          }
          ids[i] = indexes;
          if (order == 3) {
            trigrams[i] = lm.getVocabulary().encodeTrigram(indexes);
          }
          i++;
          if (i == gramCount) {
            break;
          }
        }
      }
      sw.start();
      double tr = 0;
      for (int[] id : ids) {
        tr += lm.getProbability(id);
      }
      System.out.println(sw.elapsed(TimeUnit.MILLISECONDS));
      System.out.println("tr = " + tr);
    }
  
    @Test
    public void testProbWithBackoff() throws IOException {
      SmoothLm lm = getTinyLm();
      LmVocabulary vocabulary = lm.getVocabulary();
      int ahmet = vocabulary.indexOf("Ahmet");
      int yemez = vocabulary.indexOf("yemez");
      // p(yemez|ahmet) = p(yemez) + b(ahmet) if p(yemez|ahmet) does not exist.
      double expected = -1.414973 + -0.316824;
      Assert.assertEquals(expected, lm.getProbability(ahmet, yemez), 0.0001);
    }
  
  
    @Test
    public void testTrigramBackoff() throws IOException {
      SmoothLm lm = getTinyLm();
      LmVocabulary vocabulary = lm.getVocabulary();
      int ahmet = vocabulary.indexOf("Ahmet");
      int armut = vocabulary.indexOf("armut");
      int kirmizi = vocabulary.indexOf("kırmızı");
      // p(kirmizi | Ahmet,armut) = b(ahmet, armut) + p(kırmızı|armut) if initial trigram prob does not exist.
      // if p(kırmızı|armut) also do not exist, we back off to b(ahmet, armut) + b(armut) + p(kırmızı)
      double backoffAhmetArmut = -0.124939;
      double backoffArmut = -0.492916;
      double probKirmizi = -1.539912;
  
      double expected = backoffAhmetArmut + backoffArmut + probKirmizi;
      System.out.println("expected = " + expected);
      System.out.println(lm.explain(ahmet, armut, kirmizi));
      Assert.assertEquals(expected, lm.getProbability(ahmet, armut, kirmizi), 0.0001);
      Assert.assertEquals(expected, lm.getTriGramProbability(ahmet, armut, kirmizi), 0.0001);
    }
  
    @Test
    public void testStupifBackoff() throws IOException {
      File lmFile = getTinyLmFile();
      SmoothLm lm = SmoothLm.builder(lmFile).useStupidBackoff().build();
      LmVocabulary vocabulary = lm.getVocabulary();
      int ahmet = vocabulary.indexOf("Ahmet");
      int armut = vocabulary.indexOf("armut");
      int kirmizi = vocabulary.indexOf("kırmızı");
      // p(kirmizi | Ahmet,armut) = b(ahmet, armut) + p(kırmızı|armut) if initial trigram prob does not exist.
      // if p(kırmızı|armut) also do not exist, we back off to b(ahmet, armut) + b(armut) + p(kırmızı)
      double probKirmizi = -1.539912;
      double expected = lm.getStupidBackoffLogAlpha() + lm.getStupidBackoffLogAlpha() + probKirmizi;
      System.out.println("expected = " + expected);
      System.out.println(lm.explain(ahmet, armut, kirmizi));
      Assert.assertEquals(expected, lm.getProbability(ahmet, armut, kirmizi), 0.0001);
      java.nio.file.Files.delete(lmFile.toPath());
    }
  
    @Test
    public void cacheTest() throws IOException {
      SmoothLm lm = getTinyLm();
      BaseLanguageModel.LookupCache cache = new BaseLanguageModel.LookupCache(lm);
      int[] is3 = lm.getVocabulary().toIndexes("Ahmet", "dondurma", "yedi");
      Assert.assertEquals(lm.getProbability(is3), cache.get(is3), 0.0001);
      Assert.assertEquals(lm.getProbability(is3), cache.get(is3), 0.0001);
  
      BaseLanguageModel.LookupCache cache2 = new BaseLanguageModel.LookupCache(lm);
      Assert.assertEquals(lm.getProbability(is3), cache2.get(is3), 0.0001);
      Assert.assertEquals(lm.getProbability(is3), cache2.get(is3), 0.0001);
    }
  
  
    @Test
    public void ngramExistTest() throws IOException {
      SmoothLm lm = getTinyLm();
      Assert.assertTrue(lm.ngramExists(lm.getVocabulary().toIndexes("Ahmet", "elma")));
      Assert.assertTrue(lm.ngramExists(lm.getVocabulary().toIndexes("elma")));
      Assert.assertFalse(lm.ngramExists(lm.getVocabulary().toIndexes("elma", "Ahmet")));
    }
  
    @Test
    @Ignore("Not an actual test.")
    public void loadLargeLmAndPrintInfo() throws IOException {
      SmoothLm lm = SmoothLm
          .builder(new File("/media/depo/data/asr/model/language/tr/makine-sf/lm.slm")).build();
      System.out.println(lm.info());
      System.out.println(lm.getVocabulary().size());
      System.out.println(Arrays.toString(lm.counts));
      System.out.println(lm.getVocabulary().indexOf("<UNK>"));
      System.out.println(lm.getVocabulary().indexOf("<unk>"));
    }
  }
  