Clean up and make consistent the comments in the math package.

R=rsc
CC=golang-dev
https://golang.org/cl/186042

src/pkg/math/asin.go

@@ -6,13 +6,13 @@ package math
 
 
 /*
- * asin(arg) and acos(arg) return the arcsin, arccos,
+	Floating-point sine and cosine.
- * respectively of their arguments.
- *
- * Arctan is called after appropriate range reduction.
- */
 
-// Asin returns the arc sine of x.
+	They are implemented by computing the arctangent
+	after appropriate range reduction.
+*/
+
+// Asin returns the arcsine of x.
 func Asin(x float64) float64 {
 	sign := false
 	if x < 0 {
@@ -36,5 +36,5 @@ func Asin(x float64) float64 {
 	return temp
 }
 
-// Acos returns the arc cosine of x.
+// Acos returns the arccosine of x.
 func Acos(x float64) float64 { return Pi/2 - Asin(x) }

src/pkg/math/atan.go

@@ -5,18 +5,16 @@
 package math
 
 /*
- *	floating-point arctangent
+	Floating-point arctangent.
- *
- *	atan returns the value of the arctangent of its
- *	argument in the range [-pi/2,pi/2].
- *	there are no error returns.
- *	coefficients are #5077 from Hart & Cheney. (19.56D)
- */
 
-/*
+	Atan returns the value of the arctangent of its
- *	xatan evaluates a series valid in the
+	argument in the range [-pi/2,pi/2].
- *	range [-0.414...,+0.414...]. (tan(pi/8))
+	There are no error returns.
- */
+	Coefficients are #5077 from Hart & Cheney. (19.56D)
+*/
+
+// xatan evaluates a series valid in the
+// range [-0.414...,+0.414...]. (tan(pi/8))
 func xatan(arg float64) float64 {
 	const (
 		P4 = .161536412982230228262e2
@@ -36,10 +34,8 @@ func xatan(arg float64) float64 {
 	return value * arg
 }
 
-/*
+// satan reduces its argument (known to be positive)
- *	satan reduces its argument (known to be positive)
+// to the range [0,0.414...] and calls xatan.
- *	to the range [0,0.414...] and calls xatan.
- */
 func satan(arg float64) float64 {
 	if arg < Sqrt2-1 {
 		return xatan(arg)
@@ -50,12 +46,7 @@ func satan(arg float64) float64 {
 	return Pi/4 + xatan((arg-1)/(arg+1))
 }
 
-/*
+// Atan returns the arctangent of x.
- *	Atan makes its argument positive and
- *	calls the inner routine satan.
- */
-
-// Atan returns the arc tangent of x.
 func Atan(x float64) float64 {
 	if x > 0 {
 		return satan(x)

src/pkg/math/fmod.go

@@ -6,8 +6,8 @@ package math
 
 
 /*
- *	floating-point mod func without infinity or NaN checking
+	Floating-point mod func without infinity or NaN checking
- */
+*/
 
 // Fmod returns the floating-point remainder of x/y.
 func Fmod(x, y float64) float64 {

src/pkg/math/hypot.go

@@ -5,12 +5,13 @@
 package math
 
 /*
- *	hypot -- sqrt(p*p + q*q), but overflows only if the result does.
+	Hypot -- sqrt(p*p + q*q), but overflows only if the result does.
- *	See Cleve Moler and Donald Morrison,
+	See:
- *	Replacing Square Roots by Pythagorean Sums
+		Cleve Moler and Donald Morrison,
- *	IBM Journal of Research and Development,
+		Replacing Square Roots by Pythagorean Sums
- *	Vol. 27, Number 6, pp. 577-581, Nov. 1983
+		IBM Journal of Research and Development,
- */
+		Vol. 27, Number 6, pp. 577-581, Nov. 1983
+*/
 
 // Hypot computes Sqrt(p*p + q*q), taking care to avoid
 // unnecessary overflow and underflow.

src/pkg/math/log.go

@@ -4,6 +4,9 @@
 
 package math
 
+/*
+	Floating-point logarithm.
+*/
 
 // The original C code, the long comment, and the constants
 // below are from FreeBSD's /usr/src/lib/msun/src/e_log.c

src/pkg/math/pow10.go

@@ -4,15 +4,8 @@
 
 package math
 
-/*
+// This table might overflow 127-bit exponent representations.
- * this table might overflow 127-bit exponent representations.
+// In that case, truncate it after 1.0e38.
- * in that case, truncate it after 1.0e38.
- * it is important to get all one can from this
- * routine since it is used in atof to scale numbers.
- * the presumption is that GO converts fp numbers better
- * than multipication of lower powers of 10.
- */
-
 var pow10tab [70]float64
 
 // Pow10 returns 10**e, the base-10 exponential of e.

src/pkg/math/sin.go

@@ -5,8 +5,13 @@
 package math
 
 
+/*
+	Floating-point sine and cosine.
+
+	Coefficients are #5077 from Hart & Cheney. (18.80D)
+*/
+
 func sinus(x float64, quad int) float64 {
-	// Coefficients are #3370 from Hart & Cheney (18.80D).
 	const (
 		P0 = .1357884097877375669092680e8
 		P1 = -.4942908100902844161158627e7

src/pkg/math/sinh.go

@@ -6,16 +6,16 @@ package math
 
 
 /*
- *	Sinh(x) returns the hyperbolic sine of x
+	Floating-point hyperbolic sine and cosine.
- *
+
- *	The exponential func is called for arguments
+	The exponential func is called for arguments
- *	greater in magnitude than 0.5.
+	greater in magnitude than 0.5.
- *
+
- *	A series is used for arguments smaller in magnitude than 0.5.
+	A series is used for arguments smaller in magnitude than 0.5.
- *
+
- *	Cosh(x) is computed from the exponential func for
+	Cosh(x) is computed from the exponential func for
- *	all arguments.
+	all arguments.
- */
+*/
 
 // Sinh returns the hyperbolic sine of x.
 func Sinh(x float64) float64 {

src/pkg/math/sqrt_port.go

@@ -4,6 +4,10 @@
 
 package math
 
+/*
+	Floating-point square root.
+*/
+
 // The original C code and the long comment below are
 // from FreeBSD's /usr/src/lib/msun/src/e_sqrt.c and
 // came with this notice.  The go code is a simplified

src/pkg/math/tan.go

@@ -6,8 +6,8 @@ package math
 
 
 /*
- *	floating point tangent
+	Floating point tangent.
- */
+*/
 
 // Tan returns the tangent of x.
 func Tan(x float64) float64 {

src/pkg/math/tanh.go

@@ -6,12 +6,11 @@ package math
 
 
 /*
- *	tanh(x) computes the hyperbolic tangent of its floating
+	Floating-point hyperbolic tangent.
- *	point argument.
+
- *
+	Sinh and Cosh are called except for large arguments, which
- *	sinh and cosh are called except for large arguments, which
+	would cause overflow improperly.
- *	would cause overflow improperly.
+*/
- */
 
 // Tanh computes the hyperbolic tangent of x.
 func Tanh(x float64) float64 {