parent
4ca15c909e
commit
0144471d0f
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@ -345,6 +345,12 @@
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<artifactId>opennlp-tools</artifactId>
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<version>1.8.0</version>
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</dependency>
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<dependency>
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<groupId>info.debatty</groupId>
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<artifactId>java-lsh</artifactId>
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<version>${java-lsh.version}</version>
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</dependency>
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</dependencies>
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<properties>
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@ -371,6 +377,7 @@
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<serenity.plugin.version>1.4.0</serenity.plugin.version>
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<jUnitParams.version>1.1.0</jUnitParams.version>
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<netty.version>4.1.10.Final</netty.version>
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<java-lsh.version>0.10</java-lsh.version>
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</properties>
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</project>
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@ -0,0 +1,48 @@
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package com.baeldung.lsh;
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import info.debatty.java.lsh.LSHMinHash;
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import org.junit.Ignore;
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import org.junit.Test;
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import java.util.Arrays;
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import static org.assertj.core.api.Assertions.assertThat;
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public class LocalSensitiveHashingUnitTest {
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@Ignore("for simplicity of the example number of input vectors is very low, that's why LSH may yield non deterministic results")
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@Test()
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public void givenNVectors_whenPerformLSH_thenShouldCalculateSameHashForSimilarVectors() {
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//given
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boolean[] vector1 = new boolean[]{true, true, true, true, true};
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boolean[] vector2 = new boolean[]{false, false, false, true, false};
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boolean[] vector3 = new boolean[]{false, false, true, true, false};
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int sizeOfVectors = 5;
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int numberOfBuckets = 10;
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int stages = 4;
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LSHMinHash lsh = new LSHMinHash(stages, numberOfBuckets, sizeOfVectors);
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//when
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int[] firstHash = lsh.hash(vector1);
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int[] secondHash = lsh.hash(vector2);
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int[] thirdHash = lsh.hash(vector3);
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System.out.println(Arrays.toString(firstHash));
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System.out.println(Arrays.toString(secondHash));
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System.out.println(Arrays.toString(thirdHash));
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//then
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int lastIndexOfResult = stages - 1;
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assertThat(firstHash[lastIndexOfResult]).isNotEqualTo(secondHash[lastIndexOfResult]);
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assertThat(firstHash[lastIndexOfResult]).isNotEqualTo(thirdHash[lastIndexOfResult]);
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assertThat(isCloseOrEqual(secondHash[lastIndexOfResult], thirdHash[lastIndexOfResult], numberOfBuckets)).isTrue();
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}
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private boolean isCloseOrEqual(int secondHash, int thirdHash, int numberOfBuckets) {
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return Math.abs(secondHash - thirdHash) < numberOfBuckets / 2;
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}
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}
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Reference in New Issue