@Test
public void testAxpySparseArray() {

    DenseVector y = new DenseVector(new double[] {1.0, 2.0});
    double a = 2.0;
    SparseVector x = sparseFromArray(new double[] {1.0, 2.0});
    SparseVector exp = (SparseVector)x.times(a).plus(y);
    Blas.axpy(a, x, y);
    Assert.assertTrue(elementsEqual(exp, y));
}