SlicingTestsC.java

package org.nd4j.linalg.slicing;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.nd4j.linalg.BaseNd4jTest;
import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.factory.Nd4j;
import org.nd4j.linalg.factory.Nd4jBackend;
import org.nd4j.linalg.indexing.NDArrayIndex;
import org.nd4j.linalg.indexing.SpecifiedIndex;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;

/**
 * @author Adam Gibson
 */
@RunWith(Parameterized.class)
public class SlicingTestsC extends BaseNd4jTest {

    public SlicingTestsC(Nd4jBackend backend) {
        super(backend);
    }


    @Test
    public void testSliceRowVector() {
        INDArray arr = Nd4j.zeros(5);
        System.out.println(arr.slice(1));

    }

    @Test
    public void testSliceAssertion() {
        INDArray arr = Nd4j.linspace(1, 30, 30).reshape(3, 5, 2);
        INDArray firstRow = arr.slice(0).slice(0);
        for (int i = 0; i < firstRow.length(); i++) {
            System.out.println(firstRow.getDouble(i));
        }
        System.out.println(firstRow);
    }

    @Test
    public void testSliceShape() {
        INDArray arr = Nd4j.linspace(1, 30, 30).reshape(3, 5, 2);

        INDArray sliceZero = arr.slice(0);
        for (int i = 0; i < sliceZero.rows(); i++) {
            INDArray row = sliceZero.slice(i);
            for (int j = 0; j < row.length(); j++) {
                System.out.println(row.getDouble(j));
            }
            System.out.println(row);
        }

        INDArray assertion = Nd4j.create(new double[] {1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, new int[] {5, 2});
        for (int i = 0; i < assertion.rows(); i++) {
            INDArray row = assertion.slice(i);
            for (int j = 0; j < row.length(); j++) {
                System.out.println(row.getDouble(j));
            }
            System.out.println(row);
        }
        assertArrayEquals(new int[] {5, 2}, sliceZero.shape());
        assertEquals(assertion, sliceZero);

        INDArray assertionTwo = Nd4j.create(new double[] {11, 12, 13, 14, 15, 16, 17, 18, 19, 20}, new int[] {5, 2});
        INDArray sliceTest = arr.slice(1);
        assertEquals(assertionTwo, sliceTest);
    }

    @Test
    public void testSwapReshape() {
        INDArray n2 = Nd4j.create(Nd4j.linspace(1, 30, 30).data(), new int[] {3, 5, 2});
        INDArray swapped = n2.swapAxes(n2.shape().length - 1, 1);
        INDArray firstSlice2 = swapped.slice(0).slice(0);
        INDArray oneThreeFiveSevenNine = Nd4j.create(new float[] {1, 3, 5, 7, 9});
        assertEquals(firstSlice2, oneThreeFiveSevenNine);
        INDArray raveled = oneThreeFiveSevenNine.reshape(5, 1);
        INDArray raveledOneThreeFiveSevenNine = oneThreeFiveSevenNine.reshape(5, 1);
        assertEquals(raveled, raveledOneThreeFiveSevenNine);


        INDArray firstSlice3 = swapped.slice(0).slice(1);
        INDArray twoFourSixEightTen = Nd4j.create(new float[] {2, 4, 6, 8, 10});
        assertEquals(firstSlice2, oneThreeFiveSevenNine);
        INDArray raveled2 = twoFourSixEightTen.reshape(5, 1);
        INDArray raveled3 = firstSlice3.reshape(5, 1);
        assertEquals(raveled2, raveled3);
    }


    @Test
    public void testGetRow() {
        INDArray arr = Nd4j.linspace(1, 6, 6).reshape(2, 3);
        INDArray get = arr.getRow(1);
        INDArray get2 = arr.get(NDArrayIndex.point(1), NDArrayIndex.all());
        INDArray assertion = Nd4j.create(new double[] {4, 5, 6});
        assertEquals(assertion, get);
        assertEquals(get, get2);
        get2.assign(Nd4j.linspace(1, 3, 3));
        assertEquals(Nd4j.linspace(1, 3, 3), get2);

        INDArray threeByThree = Nd4j.linspace(1, 9, 9).reshape(3, 3);
        INDArray offsetTest = threeByThree.get(new SpecifiedIndex(1, 2), NDArrayIndex.all());
        INDArray threeByThreeAssertion = Nd4j.create(new double[][] {{4, 5, 6}, {7, 8, 9}});

        assertEquals(threeByThreeAssertion, offsetTest);
    }

    @Test
    public void testVectorIndexing() {
        INDArray zeros = Nd4j.create(1, 400000);
        INDArray get = zeros.get(NDArrayIndex.interval(0, 300000));
        assertArrayEquals(new int[] {1, 300000}, get.shape());
    }



    @Override
    public char ordering() {
        return 'c';
    }
}