int log2 = DoubleMath.log2(d, FLOOR);
      assertTrue(StrictMath.pow(2.0, log2) <= d);
      assertTrue(StrictMath.pow(2.0, log2 + 1) > d);
    }
  }

  @GwtIncompatible // DoubleMath.log2(double, RoundingMode), StrictMath
  public void testRoundLog2Ceiling() {
    for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
      int log2 = DoubleMath.log2(d, CEILING);

	}
	return log10(x)
}

func log10(x float64) float64 {
	return Log(x) * (1 / Ln10)
}

// Log2 returns the binary logarithm of x.
// The special cases are the same as for [Log].
func Log2(x float64) float64 {
	if haveArchLog2 {
		return archLog2(x)
	}
	return log2(x)
}

func log2(x float64) float64 {
	frac, exp := Frexp(x)
	// Make sure exact powers of two give an exact answer.

	for i := 0; i <= (1 << fastlogNumBits); i++ {
		fastlog2Table[i] = log2(1.0 + float64(i)/(1<<fastlogNumBits))
	}
	return fastlog2Table
}

// log2 is a local copy of math.Log2 with an explicit float64 conversion
// to disable FMA. This lets us generate the same output on all platforms.
func log2(x float64) float64 {
	frac, exp := math.Frexp(x)
	// Make sure exact powers of two give an exact answer.

     * definitely >= floor(sqrt(x)), and then continue the iteration until we reach a fixed point.
     */
    BigInteger sqrt0;
    int log2 = log2(x, FLOOR);
    if (log2 < Double.MAX_EXPONENT) {
      sqrt0 = sqrtApproxWithDoubles(x);
    } else {
      int shift = (log2 - DoubleUtils.SIGNIFICAND_BITS) & ~1; // even!
      /*
       * We have that x / 2^shift < 2^54. Our initial approximation to sqrtFloor(x) will be

     * definitely >= floor(sqrt(x)), and then continue the iteration until we reach a fixed point.
     */
    BigInteger sqrt0;
    int log2 = log2(x, FLOOR);
    if (log2 < Double.MAX_EXPONENT) {
      sqrt0 = sqrtApproxWithDoubles(x);
    } else {
      int shift = (log2 - DoubleUtils.SIGNIFICAND_BITS) & ~1; // even!
      /*
       * We have that x / 2^shift < 2^54. Our initial approximation to sqrtFloor(x) will be

    return result;
  }

  /**
   * Generates a number in [0, 2^numBits) with an exponential distribution. The floor of the log2 of
   * the result is chosen uniformly at random in [0, numBits), and then the result is chosen in that
   * range uniformly at random. Zero is treated as having log2 == 0.
   */
  static BigInteger randomNonNegativeBigInteger(int numBits) {
    int digits = RANDOM_SOURCE.nextInt(numBits);

				t.Errorf("Find got (%v, %v), want (%v, %v)", pos, found, tt.wantPos, tt.wantFound)
			}
		})
	}
}

// log2 computes the binary logarithm of x, rounded up to the next integer.
// (log2(0) == 0, log2(1) == 0, log2(2) == 1, log2(3) == 2, etc.)
func log2(x int) int {
	n := 0
	for p := 1; p < x; p += p {
		// p == 2**n
		n++
	}
	// p/2 < x <= p == 2**n
	return n
}

    return result;
  }

  /**
   * Generates a number in [0, 2^numBits) with an exponential distribution. The floor of the log2 of
   * the result is chosen uniformly at random in [0, numBits), and then the result is chosen in that
   * range uniformly at random. Zero is treated as having log2 == 0.
   */
  static BigInteger randomNonNegativeBigInteger(int numBits) {
    int digits = RANDOM_SOURCE.nextInt(numBits);

func TestFastLog2(t *testing.T) {
	// Compute the euclidean distance between math.Log2 and the FastLog2
	// implementation over the range of interest for heap sampling.
	const randomBitCount = 26
	var e float64

	inc := 1
	if testing.Short() {
		// Check 1K total values, down from 64M.
		inc = 1 << 16
	}
	for i := 1; i < 1<<randomBitCount; i += inc {
		l, fl := math.Log2(float64(i)), runtime.Fastlog2(float64(i))
		d := l - fl
		e += d * d

    }
  }

  @Param({"DOWN", "UP", "FLOOR", "CEILING", "HALF_EVEN", "HALF_UP", "HALF_DOWN"})
  RoundingMode mode;

  @Benchmark
  int log2(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {
      int j = i & ARRAY_MASK;
      tmp += IntMath.log2(positive[j], mode);
    }
    return tmp;
  }

  @Benchmark
  int log10(int reps) {
    int tmp = 0;
    for (int i = 0; i < reps; i++) {