diff options
Diffstat (limited to 'src/pkg/math/tan.go')
| -rw-r--r-- | src/pkg/math/tan.go | 54 |
1 files changed, 27 insertions, 27 deletions
diff --git a/src/pkg/math/tan.go b/src/pkg/math/tan.go index 09ade2da9..05ba232a7 100644 --- a/src/pkg/math/tan.go +++ b/src/pkg/math/tan.go @@ -13,53 +13,53 @@ package math func Tan(x float64) float64 { // Coefficients are #4285 from Hart & Cheney. (19.74D) const ( - P0 = -.1306820264754825668269611177e+5; - P1 = .1055970901714953193602353981e+4; - P2 = -.1550685653483266376941705728e+2; - P3 = .3422554387241003435328470489e-1; - P4 = .3386638642677172096076369e-4; - Q0 = -.1663895238947119001851464661e+5; - Q1 = .4765751362916483698926655581e+4; - Q2 = -.1555033164031709966900124574e+3; + P0 = -.1306820264754825668269611177e+5 + P1 = .1055970901714953193602353981e+4 + P2 = -.1550685653483266376941705728e+2 + P3 = .3422554387241003435328470489e-1 + P4 = .3386638642677172096076369e-4 + Q0 = -.1663895238947119001851464661e+5 + Q1 = .4765751362916483698926655581e+4 + Q2 = -.1555033164031709966900124574e+3 ) - flag := false; - sign := false; + flag := false + sign := false if x < 0 { - x = -x; - sign = true; + x = -x + sign = true } - x = x * (4 / Pi); /* overflow? */ - var e float64; - e, x = Modf(x); - i := int32(e); + x = x * (4 / Pi) /* overflow? */ + var e float64 + e, x = Modf(x) + i := int32(e) switch i & 3 { case 1: - x = 1 - x; - flag = true; + x = 1 - x + flag = true case 2: - sign = !sign; - flag = true; + sign = !sign + flag = true case 3: - x = 1 - x; - sign = !sign; + x = 1 - x + sign = !sign } - xsq := x * x; - temp := ((((P4*xsq+P3)*xsq+P2)*xsq+P1)*xsq + P0) * x; - temp = temp / (((xsq+Q2)*xsq+Q1)*xsq + Q0); + xsq := x * x + temp := ((((P4*xsq+P3)*xsq+P2)*xsq+P1)*xsq + P0) * x + temp = temp / (((xsq+Q2)*xsq+Q1)*xsq + Q0) if flag { if temp == 0 { panic(NaN()) } - temp = 1 / temp; + temp = 1 / temp } if sign { temp = -temp } - return temp; + return temp } |