cavis/cavis-dnn/cavis-dnn-core/src/test/java/org/deeplearning4j/datasets/iterator/EarlyTerminationMultiDataSetIteratorTest.java

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package org.deeplearning4j.datasets.iterator;

import org.deeplearning4j.BaseDL4JTest;
import org.deeplearning4j.datasets.iterator.impl.MnistDataSetIterator;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.nd4j.linalg.dataset.adapter.MultiDataSetIteratorAdapter;
import org.nd4j.linalg.dataset.api.MultiDataSet;
import org.nd4j.linalg.dataset.api.iterator.MultiDataSetIterator;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import static org.junit.jupiter.api.Assertions.*;

public class EarlyTerminationMultiDataSetIteratorTest extends BaseDL4JTest {

    int minibatchSize = 5;
    int numExamples = 105;

    @Test
    public void testNextAndReset() throws Exception {

        int terminateAfter = 2;

        MultiDataSetIterator iter =
                        new MultiDataSetIteratorAdapter(new MnistDataSetIterator(minibatchSize, numExamples));

        int count = 0;
        List<MultiDataSet> seenMDS = new ArrayList<>();
        while (count < terminateAfter) {
            seenMDS.add(iter.next());
            count++;
        }
        iter.reset();

        EarlyTerminationMultiDataSetIterator earlyEndIter =
                        new EarlyTerminationMultiDataSetIterator(iter, terminateAfter);

        assertTrue(earlyEndIter.hasNext());
        count = 0;
        while (earlyEndIter.hasNext()) {
            MultiDataSet path = earlyEndIter.next();
            assertEquals(path.getFeatures()[0], seenMDS.get(count).getFeatures()[0]);
            assertEquals(path.getLabels()[0], seenMDS.get(count).getLabels()[0]);
            count++;
        }
        assertEquals(count, terminateAfter);

        //check data is repeated
        earlyEndIter.reset();
        count = 0;
        while (earlyEndIter.hasNext()) {
            MultiDataSet path = earlyEndIter.next();
            assertEquals(path.getFeatures()[0], seenMDS.get(count).getFeatures()[0]);
            assertEquals(path.getLabels()[0], seenMDS.get(count).getLabels()[0]);
            count++;
        }
    }

    @Test
    public void testNextNum() throws IOException {
        int terminateAfter = 1;

        MultiDataSetIterator iter =
                        new MultiDataSetIteratorAdapter(new MnistDataSetIterator(minibatchSize, numExamples));
        EarlyTerminationMultiDataSetIterator earlyEndIter =
                        new EarlyTerminationMultiDataSetIterator(iter, terminateAfter);

        earlyEndIter.next(10);
        assertFalse(earlyEndIter.hasNext());

        earlyEndIter.reset();
        assertTrue(earlyEndIter.hasNext());
    }

    @Test
    public void testCallstoNextNotAllowed() throws IOException {
        int terminateAfter = 1;

        MultiDataSetIterator iter =
                        new MultiDataSetIteratorAdapter(new MnistDataSetIterator(minibatchSize, numExamples));
        EarlyTerminationMultiDataSetIterator earlyEndIter =
                        new EarlyTerminationMultiDataSetIterator(iter, terminateAfter);

        earlyEndIter.next(10);
        iter.reset();
        Assertions.assertThrows(RuntimeException.class, () -> {
            earlyEndIter.next(10);
        });
    }

}