コード例 #1
0
ファイル: ArithmeticUtilsTest.java プロジェクト: mfwzan/astor
  @Test
  public void testBinomialCoefficient() {
    long[] bcoef5 = {1, 5, 10, 10, 5, 1};
    long[] bcoef6 = {1, 6, 15, 20, 15, 6, 1};
    for (int i = 0; i < 6; i++) {
      Assert.assertEquals("5 choose " + i, bcoef5[i], ArithmeticUtils.binomialCoefficient(5, i));
    }
    for (int i = 0; i < 7; i++) {
      Assert.assertEquals("6 choose " + i, bcoef6[i], ArithmeticUtils.binomialCoefficient(6, i));
    }

    for (int n = 1; n < 10; n++) {
      for (int k = 0; k <= n; k++) {
        Assert.assertEquals(
            n + " choose " + k,
            binomialCoefficient(n, k),
            ArithmeticUtils.binomialCoefficient(n, k));
        Assert.assertEquals(
            n + " choose " + k,
            binomialCoefficient(n, k),
            ArithmeticUtils.binomialCoefficientDouble(n, k),
            Double.MIN_VALUE);
        Assert.assertEquals(
            n + " choose " + k,
            FastMath.log(binomialCoefficient(n, k)),
            ArithmeticUtils.binomialCoefficientLog(n, k),
            10E-12);
      }
    }

    int[] n = {34, 66, 100, 1500, 1500};
    int[] k = {17, 33, 10, 1500 - 4, 4};
    for (int i = 0; i < n.length; i++) {
      long expected = binomialCoefficient(n[i], k[i]);
      Assert.assertEquals(
          n[i] + " choose " + k[i], expected, ArithmeticUtils.binomialCoefficient(n[i], k[i]));
      Assert.assertEquals(
          n[i] + " choose " + k[i],
          expected,
          ArithmeticUtils.binomialCoefficientDouble(n[i], k[i]),
          0.0);
      Assert.assertEquals(
          "log(" + n[i] + " choose " + k[i] + ")",
          FastMath.log(expected),
          ArithmeticUtils.binomialCoefficientLog(n[i], k[i]),
          0.0);
    }
  }
コード例 #2
0
ファイル: ArithmeticUtilsTest.java プロジェクト: mfwzan/astor
  @Test
  public void testFactorial() {
    for (int i = 1; i < 21; i++) {
      Assert.assertEquals(i + "! ", factorial(i), ArithmeticUtils.factorial(i));
      Assert.assertEquals(
          i + "! ", factorial(i), ArithmeticUtils.factorialDouble(i), Double.MIN_VALUE);
      Assert.assertEquals(
          i + "! ", FastMath.log(factorial(i)), ArithmeticUtils.factorialLog(i), 10E-12);
    }

    Assert.assertEquals("0", 1, ArithmeticUtils.factorial(0));
    Assert.assertEquals("0", 1.0d, ArithmeticUtils.factorialDouble(0), 1E-14);
    Assert.assertEquals("0", 0.0d, ArithmeticUtils.factorialLog(0), 1E-14);
  }
コード例 #3
0
ファイル: ArithmeticUtilsTest.java プロジェクト: mfwzan/astor
  /** Tests correctness for large n and sharpness of upper bound in API doc JIRA: MATH-241 */
  @Test
  public void testBinomialCoefficientLarge() throws Exception {
    // This tests all legal and illegal values for n <= 200.
    for (int n = 0; n <= 200; n++) {
      for (int k = 0; k <= n; k++) {
        long ourResult = -1;
        long exactResult = -1;
        boolean shouldThrow = false;
        boolean didThrow = false;
        try {
          ourResult = ArithmeticUtils.binomialCoefficient(n, k);
        } catch (MathArithmeticException ex) {
          didThrow = true;
        }
        try {
          exactResult = binomialCoefficient(n, k);
        } catch (MathArithmeticException ex) {
          shouldThrow = true;
        }
        Assert.assertEquals(n + " choose " + k, exactResult, ourResult);
        Assert.assertEquals(n + " choose " + k, shouldThrow, didThrow);
        Assert.assertTrue(n + " choose " + k, (n > 66 || !didThrow));

        if (!shouldThrow && exactResult > 1) {
          Assert.assertEquals(
              n + " choose " + k,
              1.,
              ArithmeticUtils.binomialCoefficientDouble(n, k) / exactResult,
              1e-10);
          Assert.assertEquals(
              n + " choose " + k,
              1,
              ArithmeticUtils.binomialCoefficientLog(n, k) / FastMath.log(exactResult),
              1e-10);
        }
      }
    }

    long ourResult = ArithmeticUtils.binomialCoefficient(300, 3);
    long exactResult = binomialCoefficient(300, 3);
    Assert.assertEquals(exactResult, ourResult);

    ourResult = ArithmeticUtils.binomialCoefficient(700, 697);
    exactResult = binomialCoefficient(700, 697);
    Assert.assertEquals(exactResult, ourResult);

    // This one should throw
    try {
      ArithmeticUtils.binomialCoefficient(700, 300);
      Assert.fail("Expecting MathArithmeticException");
    } catch (MathArithmeticException ex) {
      // Expected
    }

    int n = 10000;
    ourResult = ArithmeticUtils.binomialCoefficient(n, 3);
    exactResult = binomialCoefficient(n, 3);
    Assert.assertEquals(exactResult, ourResult);
    Assert.assertEquals(1, ArithmeticUtils.binomialCoefficientDouble(n, 3) / exactResult, 1e-10);
    Assert.assertEquals(
        1, ArithmeticUtils.binomialCoefficientLog(n, 3) / FastMath.log(exactResult), 1e-10);
  }