atanh(p1)
public
Computes the inverse hyperbolic tangent of x.
static VALUE
math_atanh(VALUE obj, VALUE x)
{
double d0, d;
Need_Float(x);
d0 = RFLOAT_VALUE(x);
/* check for domain error */
if (d0 < -1.0 || +1.0 < d0) domain_error("atanh");
/* check for pole error */
if (d0 == -1.0) return DBL2NUM(-INFINITY);
if (d0 == +1.0) return DBL2NUM(+INFINITY);
d = atanh(d0);
return DBL2NUM(d);
}
