/*
- * asin(arg) and acos(arg) return the arcsin, arccos,
- * respectively of their arguments.
- *
- * Arctan is called after appropriate range reduction.
- */
+ Floating-point sine and cosine.
-// 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 {
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) }
package math
/*
- * 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)
- */
+ Floating-point arctangent.
-/*
- * xatan evaluates a series valid in the
- * range [-0.414...,+0.414...]. (tan(pi/8))
- */
+ 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)
+*/
+
+// xatan evaluates a series valid in the
+// range [-0.414...,+0.414...]. (tan(pi/8))
func xatan(arg float64) float64 {
const (
P4 = .161536412982230228262e2
return value * arg
}
-/*
- * satan reduces its argument (known to be positive)
- * to the range [0,0.414...] and calls xatan.
- */
+// satan reduces its argument (known to be positive)
+// to the range [0,0.414...] and calls xatan.
func satan(arg float64) float64 {
if arg < Sqrt2-1 {
return xatan(arg)
return Pi/4 + xatan((arg-1)/(arg+1))
}
-/*
- * Atan makes its argument positive and
- * calls the inner routine satan.
- */
-
-// Atan returns the arc tangent of x.
+// Atan returns the arctangent of x.
func Atan(x float64) float64 {
if x > 0 {
return satan(x)
/*
- * 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 {
package math
/*
- * hypot -- sqrt(p*p + q*q), but overflows only if the result does.
- * See Cleve Moler and Donald Morrison,
- * Replacing Square Roots by Pythagorean Sums
- * IBM Journal of Research and Development,
- * Vol. 27, Number 6, pp. 577-581, Nov. 1983
- */
+ Hypot -- sqrt(p*p + q*q), but overflows only if the result does.
+ See:
+ Cleve Moler and Donald Morrison,
+ Replacing Square Roots by Pythagorean Sums
+ 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.
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
package math
-/*
- * this table might overflow 127-bit exponent representations.
- * 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.
- */
-
+// This table might overflow 127-bit exponent representations.
+// In that case, truncate it after 1.0e38.
var pow10tab [70]float64
// Pow10 returns 10**e, the base-10 exponential of e.
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
/*
- * Sinh(x) returns the hyperbolic sine of x
- *
- * The exponential func is called for arguments
- * greater 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
- * all arguments.
- */
+ Floating-point hyperbolic sine and cosine.
+
+ The exponential func is called for arguments
+ greater 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
+ all arguments.
+*/
// Sinh returns the hyperbolic sine of x.
func Sinh(x float64) float64 {
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
/*
- * floating point tangent
- */
+ Floating point tangent.
+*/
// Tan returns the tangent of x.
func Tan(x float64) float64 {
/*
- * tanh(x) computes the hyperbolic tangent of its floating
- * point argument.
- *
- * sinh and cosh are called except for large arguments, which
- * would cause overflow improperly.
- */
+ Floating-point hyperbolic tangent.
+
+ Sinh and Cosh are called except for large arguments, which
+ would cause overflow improperly.
+*/
// Tanh computes the hyperbolic tangent of x.
func Tanh(x float64) float64 {