예제 #1
0
  /**
   * tests the firstDerivative function by comparison
   *
   * <p>This will test the functions <tt>f(x) = x^3 - 2x^2 + 6x + 3, g(x) = 3x^2 - 4x + 6</tt> and
   * <tt>h(x) = 6x - 4</tt>
   */
  public void testfirstDerivativeComparison() throws MathException {
    double[] f_coeff = {3.0, 6.0, -2.0, 1.0};
    double[] g_coeff = {6.0, -4.0, 3.0};
    double[] h_coeff = {-4.0, 6.0};

    PolynomialFunction f = new PolynomialFunction(f_coeff);
    PolynomialFunction g = new PolynomialFunction(g_coeff);
    PolynomialFunction h = new PolynomialFunction(h_coeff);

    // compare f' = g
    assertEquals(f.derivative().value(0.0), g.value(0.0), tolerance);
    assertEquals(f.derivative().value(1.0), g.value(1.0), tolerance);
    assertEquals(f.derivative().value(100.0), g.value(100.0), tolerance);
    assertEquals(f.derivative().value(4.1), g.value(4.1), tolerance);
    assertEquals(f.derivative().value(-3.25), g.value(-3.25), tolerance);

    // compare g' = h
    assertEquals(g.derivative().value(Math.PI), h.value(Math.PI), tolerance);
    assertEquals(g.derivative().value(Math.E), h.value(Math.E), tolerance);
  }
예제 #2
0
  /**
   * tests the value of a constant polynomial.
   *
   * <p>value of this is 2.5 everywhere.
   */
  public void testConstants() throws MathException {
    double[] c = {2.5};
    PolynomialFunction f = new PolynomialFunction(c);

    // verify that we are equal to c[0] at several (nonsymmetric) places
    assertEquals(f.value(0.0), c[0], tolerance);
    assertEquals(f.value(-1.0), c[0], tolerance);
    assertEquals(f.value(-123.5), c[0], tolerance);
    assertEquals(f.value(3.0), c[0], tolerance);
    assertEquals(f.value(456.89), c[0], tolerance);

    assertEquals(f.degree(), 0);
    assertEquals(f.derivative().value(0), 0, tolerance);

    assertEquals(f.polynomialDerivative().derivative().value(0), 0, tolerance);
  }