blob: 6bbf88088be6f54b45f86d3e62bf77bc8db770bb (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
module math
// sinh calculates hyperbolic sine.
pub fn sinh(x_ f64) f64 {
mut x := x_
// The coefficients are #2029 from Hart & Cheney. (20.36D)
p0 := -0.6307673640497716991184787251e+6
p1 := -0.8991272022039509355398013511e+5
p2 := -0.2894211355989563807284660366e+4
p3 := -0.2630563213397497062819489e+2
q0 := -0.6307673640497716991212077277e+6
q1 := 0.1521517378790019070696485176e+5
q2 := -0.173678953558233699533450911e+3
mut sign := false
if x < 0 {
x = -x
sign = true
}
mut temp := 0.0
if x > 21 {
temp = exp(x) * 0.5
} else if x > 0.5 {
ex := exp(x)
temp = (ex - 1.0 / ex) * 0.5
} else {
sq := x * x
temp = (((p3 * sq + p2) * sq + p1) * sq + p0) * x
temp = temp / (((sq + q2) * sq + q1) * sq + q0)
}
if sign {
temp = -temp
}
return temp
}
// cosh returns the hyperbolic cosine of x.
//
// special cases are:
// cosh(±0) = 1
// cosh(±inf) = +inf
// cosh(nan) = nan
pub fn cosh(x f64) f64 {
abs_x := abs(x)
if abs_x > 21 {
return exp(abs_x) * 0.5
}
ex := exp(abs_x)
return (ex + 1.0 / ex) * 0.5
}
|
