@Test
public void testCubic() {
ComplexNumber[] result = CUBIC.getRoots(ONE_REAL_ROOT);
assertEquals(result.length, 3);
assertComplexEquals(result[0], new ComplexNumber(1, 0));
assertComplexEquals(result[1], new ComplexNumber(0, Math.sqrt(10 / 3.)));
assertComplexEquals(result[2], new ComplexNumber(0, -Math.sqrt(10 / 3.)));
result = CUBIC.getRoots(ONE_DISTINCT_ROOT);
assertEquals(result.length, 3);
for (final ComplexNumber c : result) {
assertComplexEquals(c, new ComplexNumber(1, 0));
}
result = CUBIC.getRoots(THREE_ROOTS);
assertEquals(result.length, 3);
assertComplexEquals(result[0], new ComplexNumber(1, 0));
assertComplexEquals(result[1], new ComplexNumber(3, 0));
assertComplexEquals(result[2], new ComplexNumber(2, 0));
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testNonCubic1() {
CUBIC.getRoots(new RealPolynomialFunction1D(new double[] {1, 1, 1, 1, 1}));
}
@Test(expectedExceptions = IllegalArgumentException.class)
public void testNullFunction1() {
CUBIC.getRoots(null);
}