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Annotation of 3BSD/libF77/sinh.c, revision 1.1

1.1     ! root        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: }

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