Commit | Line | Data |
---|---|---|
0c9e74ab TL |
1 | /* |
2 | sinh(arg) returns the hyperbolic sign of its floating- | |
3 | point argument. | |
4 | ||
5 | The exponential function is called for arguments | |
6 | greater in magnitude than 0.5. | |
7 | The result overflows and 'huge' is returned for | |
8 | arguments greater than somewhat. | |
9 | ||
10 | A series is used for arguments smaller in magnitude than 0.5. | |
11 | The coeffieients are #2029 from Hart & Cheney. (20.36D) | |
12 | ||
13 | cosh(arg) is computed from the exponential function for | |
14 | all arguments. | |
15 | */ | |
16 | ||
17 | double exp(); | |
18 | ||
19 | static double p0 -0.6307673640497716991184787251e+6; | |
20 | static double p1 -0.8991272022039509355398013511e+5; | |
21 | static double p2 -0.2894211355989563807284660366e+4; | |
22 | static double p3 -0.2630563213397497062819489e+2; | |
23 | static double q0 -0.6307673640497716991212077277e+6; | |
24 | static double q1 0.1521517378790019070696485176e+5; | |
25 | static double q2 -0.173678953558233699533450911e+3; | |
26 | static double q3 1.0; | |
27 | ||
28 | double | |
29 | sinh(arg) double arg; { | |
30 | ||
31 | double sign, temp, argsq; | |
32 | ||
33 | sign = 1; | |
34 | if(arg < 0){ | |
35 | arg = - arg; | |
36 | sign = -1; | |
37 | } | |
38 | ||
39 | if(arg > 21.){ | |
40 | temp = exp(arg)/2; | |
41 | return(sign*temp); | |
42 | } | |
43 | ||
44 | if(arg > 0.5) { | |
45 | temp = (exp(arg) - exp(-arg))/2; | |
46 | return(sign*temp); | |
47 | } | |
48 | ||
49 | argsq = arg*arg; | |
50 | temp = (((p3*argsq+p2)*argsq+p1)*argsq+p0)*arg; | |
51 | temp = temp/(((q3*argsq+q2)*argsq+q1)*argsq+q0); | |
52 | return(sign*temp); | |
53 | ||
54 | } | |
55 | ||
56 | double | |
57 | cosh(arg) double arg; { | |
58 | ||
59 | double temp; | |
60 | ||
61 | if(arg < 0) | |
62 | arg = - arg; | |
63 | ||
64 | if(arg > 21.){ | |
65 | temp = exp(arg)/2; | |
66 | return(temp); | |
67 | } | |
68 | ||
69 | temp = (exp(arg) + exp(-arg))/2; | |
70 | return(temp); | |
71 | } |