#	Powers of 2.
#	%.20g versions.
#	random sources
#	random targets
#	random targets ± half a ULP

# Difficult boundary cases, derived from tables given in
#	Vern Paxson, A Program for Testing IEEE Decimal-Binary Conversion
#	ftp://ftp.ee.lbl.gov/testbase-report.ps.Z

# Table 1: Stress Inputs for Conversion to 53-bit Binary, < 1/2 ULP
float64 %b 5e+125 6653062250012735p+365
float64 %b 69e+267 4705683757438170p+841

	"fmt"
	"math"
	"runtime"
)

const ulp = (1.0 + (2.0 / 3.0)) - (5.0 / 3.0)

func main() {
	// adjust precision depending on compiler
	var prec float64
	switch runtime.Compiler {
	case "gc":
		prec = math.Inf(1) // exact precision using rational arithmetic
	case "gccgo":
		prec = 256
	default:
		// unknown compiler
		return
	}
	p := 1 - math.Log(math.Abs(ulp))/math.Log(2)
	if math.Abs(p-prec) > 1e-10 {

    }
  }

  @GwtIncompatible // #trueLog2, Math.ulp
  public void testLog2Accuracy() {
    for (double d : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
      double dmLog2 = DoubleMath.log2(d);
      double trueLog2 = trueLog2(d);
      assertTrue(Math.abs(dmLog2 - trueLog2) <= Math.ulp(trueLog2));
    }
  }

  public void testLog2SemiMonotonic() {

//      log1p(+INF) is +INF; log1p(-1) is -INF with signal;
//      log1p(NaN) is that NaN with no signal.
//
// Accuracy:
//      according to an error analysis, the error is always less than
//      1 ulp (unit in the last place).
//
// Constants:
// The hexadecimal values are the intended ones for the following
// constants. The decimal values may be used, provided that the

	// that the lsb of mant corresponds to 1/2 ulp for the precision of
	// x (i.e., for mant we want x.prec + 1 bits).
	mant := nat(nil).set(x.mant)
	exp := int(x.exp) - mant.bitLen()
	s := mant.bitLen() - int(x.prec+1)
	switch {
	case s < 0:
		mant = mant.shl(mant, uint(-s))
	case s > 0:
		mant = mant.shr(mant, uint(+s))
	}
	exp += s
	// x = mant * 2**exp with lsb(mant) == 1/2 ulp of x.prec

	// Table 14: Stress Inputs for Conversion to 24-bit Binary, <1/2 ULP
	"5e-20",
	"67e+14",
	"985e+15",
	"7693e-42",
	"55895e-16",
	"996622e-44",
	"7038531e-32",
	"60419369e-46",
	"702990899e-20",
	"6930161142e-48",
	"25933168707e+13",
	"596428896559e+20",

	// Table 15: Stress Inputs for Conversion to 24-bit Binary, >1/2 ULP
	"3e-23",
	"57e+18",
	"789e-35",
	"2539e-18",

// and include err.Num = s.
//
// If s is not syntactically well-formed, ParseComplex returns err.Err = ErrSyntax.
//
// If s is syntactically well-formed but either component is more than 1/2 ULP
// away from the largest floating point number of the given component's size,
// ParseComplex returns err.Err = ErrRange and c = ±Inf for the respective component.
func ParseComplex(s string, bitSize int) (complex128, error) {

//	log(+INF) is +INF; log(0) is -INF with signal;
//	log(NaN) is that NaN with no signal.
//
// Accuracy:
//	according to an error analysis, the error is always less than
//	1 ulp (unit in the last place).
//
// Constants:
// The hexadecimal values are the intended ones for the following
// constants. The decimal values may be used, provided that the

   * </ul>
   *
   * <p>The computed result is within 1 ulp of the exact result.
   *
   * <p>If the result of this method will be immediately rounded to an {@code int}, {@link
   * #log2(double, RoundingMode)} is faster.
   */
  public static double log2(double x) {
    return log(x) / LN_2; // surprisingly within 1 ulp according to tests
  }

  /**

   * </ul>
   *
   * <p>The computed result is within 1 ulp of the exact result.
   *
   * <p>If the result of this method will be immediately rounded to an {@code int}, {@link
   * #log2(double, RoundingMode)} is faster.
   */
  public static double log2(double x) {
    return log(x) / LN_2; // surprisingly within 1 ulp according to tests
  }

  /**