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Annotation of 41BSD/lib/libF77/sinh.c, revision 1.1.1.1

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

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