prettify code

math/exp.go

@@ -5,6 +5,8 @@ import (
 	"math/big"
 )
 
+// https://github.com/ALTree/bigfloat
+
 // Exp returns a big.Float representation of exp(z). Precision is
 // the same as the one of the argument. The function returns +Inf
 // when z = +Inf, and 0 when z = -Inf.

math/log.go

@@ -5,6 +5,8 @@ import (
 	"math/big"
 )
 
+// https://github.com/ALTree/bigfloat
+
 // Log returns a big.Float representation of the natural logarithm of
 // z. Precision is the same as the one of the argument. The function
 // panics if z is negative, returns -Inf when z = 0, and +Inf when z =

math/misc.go

@@ -2,6 +2,8 @@ package math
 
 import "math/big"
 
+// https://github.com/ALTree/bigfloat
+
 // agm returns the arithmetic-geometric mean of a and b.
 // a and b must have the same precision.
 func agm(a, b *big.Float) *big.Float {

math/pow.go

@@ -2,6 +2,8 @@ package math
 
 import "math/big"
 
+// https://github.com/ALTree/bigfloat
+
 // Pow returns a big.Float representation of z**w. Precision is the same as the one
 // of the first argument. The function panics when z is negative.
 func Pow(z *big.Float, w *big.Float) *big.Float {
@@ -29,13 +31,6 @@ func Pow(z *big.Float, w *big.Float) *big.Float {
 		return x.Quo(big.NewFloat(1), Pow(zExt, wNeg)).SetPrec(z.Prec())
 	}
 
-	// w integer fast path (disabled because introduces rounding
-	// errors)
-	if false && w.IsInt() {
-		wi, _ := w.Int64()
-		return powInt(z, int(wi))
-	}
-
 	// compute w**z as exp(z log(w))
 	x := new(big.Float).SetPrec(z.Prec() + 64)
 	logZ := Log(new(big.Float).Copy(z).SetPrec(z.Prec() + 64))
@@ -44,28 +39,3 @@ func Pow(z *big.Float, w *big.Float) *big.Float {
 	return x.SetPrec(z.Prec())
 
 }
-
-// fast path for z**w when w is an integer
-func powInt(z *big.Float, w int) *big.Float {
-
-	// get mantissa and exponent of z
-	mant := new(big.Float)
-	exp := z.MantExp(mant)
-
-	// result's exponent
-	exp = exp * w
-
-	// result's mantissa
-	x := big.NewFloat(1).SetPrec(z.Prec())
-
-	// Classic right-to-left binary exponentiation
-	for w > 0 {
-		if w%2 == 1 {
-			x.Mul(x, mant)
-		}
-		w >>= 1
-		mant.Mul(mant, mant)
-	}
-
-	return new(big.Float).SetMantExp(x, exp)
-}