Imported Upstream version 1.4upstream/1.4

1 files changed, 0 insertions, 200 deletions

diff --git a/src/pkg/math/log1p.go b/src/pkg/math/log1p.go
deleted file mode 100644
index 12b98684c..000000000
--- a/src/pkg/math/log1p.go
+++ /dev/null
@@ -1,200 +0,0 @@
-// Copyright 2010 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package math
-
-// The original C code, the long comment, and the constants
-// below are from FreeBSD's /usr/src/lib/msun/src/s_log1p.c
-// and came with this notice.  The go code is a simplified
-// version of the original C.
-//
-// ====================================================
-// Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
-//
-// Developed at SunPro, a Sun Microsystems, Inc. business.
-// Permission to use, copy, modify, and distribute this
-// software is freely granted, provided that this notice
-// is preserved.
-// ====================================================
-//
-//
-// double log1p(double x)
-//
-// Method :
-//   1. Argument Reduction: find k and f such that
-//                      1+x = 2**k * (1+f),
-//         where  sqrt(2)/2 < 1+f < sqrt(2) .
-//
-//      Note. If k=0, then f=x is exact. However, if k!=0, then f
-//      may not be representable exactly. In that case, a correction
-//      term is need. Let u=1+x rounded. Let c = (1+x)-u, then
-//      log(1+x) - log(u) ~ c/u. Thus, we proceed to compute log(u),
-//      and add back the correction term c/u.
-//      (Note: when x > 2**53, one can simply return log(x))
-//
-//   2. Approximation of log1p(f).
-//      Let s = f/(2+f) ; based on log(1+f) = log(1+s) - log(1-s)
-//               = 2s + 2/3 s**3 + 2/5 s**5 + .....,
-//               = 2s + s*R
-//      We use a special Reme algorithm on [0,0.1716] to generate
-//      a polynomial of degree 14 to approximate R The maximum error
-//      of this polynomial approximation is bounded by 2**-58.45. In
-//      other words,
-//                      2      4      6      8      10      12      14
-//          R(z) ~ Lp1*s +Lp2*s +Lp3*s +Lp4*s +Lp5*s  +Lp6*s  +Lp7*s
-//      (the values of Lp1 to Lp7 are listed in the program)
-//      and
-//          |      2          14          |     -58.45
-//          | Lp1*s +...+Lp7*s    -  R(z) | <= 2
-//          |                             |
-//      Note that 2s = f - s*f = f - hfsq + s*hfsq, where hfsq = f*f/2.
-//      In order to guarantee error in log below 1ulp, we compute log
-//      by
-//              log1p(f) = f - (hfsq - s*(hfsq+R)).
-//
-//   3. Finally, log1p(x) = k*ln2 + log1p(f).
-//                        = k*ln2_hi+(f-(hfsq-(s*(hfsq+R)+k*ln2_lo)))
-//      Here ln2 is split into two floating point number:
-//                   ln2_hi + ln2_lo,
-//      where n*ln2_hi is always exact for |n| < 2000.
-//
-// Special cases:
-//      log1p(x) is NaN with signal if x < -1 (including -INF) ;
-//      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
-// compiler will convert from decimal to binary accurately enough
-// to produce the hexadecimal values shown.
-//
-// Note: Assuming log() return accurate answer, the following
-//       algorithm can be used to compute log1p(x) to within a few ULP:
-//
-//              u = 1+x;
-//              if(u==1.0) return x ; else
-//                         return log(u)*(x/(u-1.0));
-//
-//       See HP-15C Advanced Functions Handbook, p.193.
-
-// Log1p returns the natural logarithm of 1 plus its argument x.
-// It is more accurate than Log(1 + x) when x is near zero.
-//
-// Special cases are:
-//	Log1p(+Inf) = +Inf
-//	Log1p(±0) = ±0
-//	Log1p(-1) = -Inf
-//	Log1p(x < -1) = NaN
-//	Log1p(NaN) = NaN
-func Log1p(x float64) float64
-
-func log1p(x float64) float64 {
-	const (
-		Sqrt2M1     = 4.142135623730950488017e-01  // Sqrt(2)-1 = 0x3fda827999fcef34
-		Sqrt2HalfM1 = -2.928932188134524755992e-01 // Sqrt(2)/2-1 = 0xbfd2bec333018866
-		Small       = 1.0 / (1 << 29)              // 2**-29 = 0x3e20000000000000
-		Tiny        = 1.0 / (1 << 54)              // 2**-54
-		Two53       = 1 << 53                      // 2**53
-		Ln2Hi       = 6.93147180369123816490e-01   // 3fe62e42fee00000
-		Ln2Lo       = 1.90821492927058770002e-10   // 3dea39ef35793c76
-		Lp1         = 6.666666666666735130e-01     // 3FE5555555555593
-		Lp2         = 3.999999999940941908e-01     // 3FD999999997FA04
-		Lp3         = 2.857142874366239149e-01     // 3FD2492494229359
-		Lp4         = 2.222219843214978396e-01     // 3FCC71C51D8E78AF
-		Lp5         = 1.818357216161805012e-01     // 3FC7466496CB03DE
-		Lp6         = 1.531383769920937332e-01     // 3FC39A09D078C69F
-		Lp7         = 1.479819860511658591e-01     // 3FC2F112DF3E5244
-	)
-
-	// special cases
-	switch {
-	case x < -1 || IsNaN(x): // includes -Inf
-		return NaN()
-	case x == -1:
-		return Inf(-1)
-	case IsInf(x, 1):
-		return Inf(1)
-	}
-
-	absx := x
-	if absx < 0 {
-		absx = -absx
-	}
-
-	var f float64
-	var iu uint64
-	k := 1
-	if absx < Sqrt2M1 { //  |x| < Sqrt(2)-1
-		if absx < Small { // |x| < 2**-29
-			if absx < Tiny { // |x| < 2**-54
-				return x
-			}
-			return x - x*x*0.5
-		}
-		if x > Sqrt2HalfM1 { // Sqrt(2)/2-1 < x
-			// (Sqrt(2)/2-1) < x < (Sqrt(2)-1)
-			k = 0
-			f = x
-			iu = 1
-		}
-	}
-	var c float64
-	if k != 0 {
-		var u float64
-		if absx < Two53 { // 1<<53
-			u = 1.0 + x
-			iu = Float64bits(u)
-			k = int((iu >> 52) - 1023)
-			if k > 0 {
-				c = 1.0 - (u - x)
-			} else {
-				c = x - (u - 1.0) // correction term
-				c /= u
-			}
-		} else {
-			u = x
-			iu = Float64bits(u)
-			k = int((iu >> 52) - 1023)
-			c = 0
-		}
-		iu &= 0x000fffffffffffff
-		if iu < 0x0006a09e667f3bcd { // mantissa of Sqrt(2)
-			u = Float64frombits(iu | 0x3ff0000000000000) // normalize u
-		} else {
-			k += 1
-			u = Float64frombits(iu | 0x3fe0000000000000) // normalize u/2
-			iu = (0x0010000000000000 - iu) >> 2
-		}
-		f = u - 1.0 // Sqrt(2)/2 < u < Sqrt(2)
-	}
-	hfsq := 0.5 * f * f
-	var s, R, z float64
-	if iu == 0 { // |f| < 2**-20
-		if f == 0 {
-			if k == 0 {
-				return 0
-			} else {
-				c += float64(k) * Ln2Lo
-				return float64(k)*Ln2Hi + c
-			}
-		}
-		R = hfsq * (1.0 - 0.66666666666666666*f) // avoid division
-		if k == 0 {
-			return f - R
-		}
-		return float64(k)*Ln2Hi - ((R - (float64(k)*Ln2Lo + c)) - f)
-	}
-	s = f / (2.0 + f)
-	z = s * s
-	R = z * (Lp1 + z*(Lp2+z*(Lp3+z*(Lp4+z*(Lp5+z*(Lp6+z*Lp7))))))
-	if k == 0 {
-		return f - (hfsq - s*(hfsq+R))
-	}
-	return float64(k)*Ln2Hi - ((hfsq - (s*(hfsq+R) + (float64(k)*Ln2Lo + c))) - f)
-}