result of atanh is never more precise than double

5 results were exact to double the precision

20 largest ulp errors (stored in a double)
   24116.03784 ulp for atanh(0.999999999612201096) = 11.1818406896726241)
   24109.54302 ulp for atanh(0.999999999612180113) = 11.1818136361569049)
   24109.16414 ulp for atanh(0.999999999612178336) = 11.1818113459793906)
   24105.48882 ulp for atanh(0.999999999612169455) = 11.1817998952491671)
   21453.46165 ulp for atanh(0.999999999451925414) = 11.0088784566418578)
   21434.21944 ulp for atanh(0.999999999452005461) = 11.0089514876929329)
   21429.75582 ulp for atanh(0.999999999452020449) = 11.0089651632086003)
   21427.03752 ulp for atanh(0.999999999452035437) = 11.0089788390983205)
   21425.76509 ulp for atanh(0.999999999452040544) = 11.0089834991165585)
   21425.02215 ulp for atanh(0.999999999452039878) = 11.008982891285628)
   21391.10211 ulp for atanh(0.999999999452180544) = 11.0091112613162121)
   20938.70344 ulp for atanh(0.999999999454046495) = 11.0108172402658617)
   19211.80501 ulp for atanh(0.999999999597616318) = 11.163381115059769)
   18592.06908 ulp for atanh(0.999999999256802052) = 10.8566029350444637)
   18591.10672 ulp for atanh(0.99999999925680072) = 10.8566020387378757)
   18577.73311 ulp for atanh(0.999999999256755756) = 10.8565717893326532)
   18563.61309 ulp for atanh(0.99999999925670946) = 10.8565406455608322)
   18399.24311 ulp for atanh(0.999999999256174332) = 10.8561808031235909)
   17662.87216 ulp for atanh(0.999999999253766259) = 10.8545647092813322)
   15090.54358 ulp for atanh(0.999999999285664409) = 10.876407714655512)

<tr><td align=left><a href=atanh.res>atanh</a></td><td align=right>993</td><td align=right>24116.03784</td><td>0.999999999612201096</td><td>11.1818406896726241</td></tr>