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) 97551793252583.82812 ulp for atanh(0.999999999999999889) = 18.3684002848385504) 57064140930864.52344 ulp for atanh(-0.999999999999999667) = -18.3684002848385504) 57064140930864.52344 ulp for atanh(0.999999999999999667) = 18.3684002848385504) 80633234.45698 ulp for atanh(0.999999999612180113) = 11.1818137794331296) 80632865.83586 ulp for atanh(0.999999999612178336) = 11.1818114892549598) 80631021.51118 ulp for atanh(0.999999999612169455) = 11.1818000385214535) 57121446.10211 ulp for atanh(0.999999999452180544) = 11.0091113627462853) 56950548.24418 ulp for atanh(0.999999999452020449) = 11.0089650620060375) 56940646.53835 ulp for atanh(0.999999999451925414) = 11.0088783554568419) 47031896.89016 ulp for atanh(0.999999999334230893) = 10.9116127698677747) 46812123.30763 ulp for atanh(0.999999999333772371) = 10.9112683664921413) 46811872.28743 ulp for atanh(0.999999999333768819) = 10.9112657002085314) 46810619.36891 ulp for atanh(0.999999999333751055) = 10.911252369003746) 43923101.17956 ulp for atanh(0.999999999286899866) = 10.8772733002672801) 43847482.54358 ulp for atanh(0.999999999285664409) = 10.8764077925174814) 43735494.46570 ulp for atanh(0.999999999287112806) = 10.8774224732149527) 41940792.73311 ulp for atanh(0.999999999256755756) = 10.8565717148638399) 22575462.65854 ulp for atanh(0.999999998603597562) = 10.5412569273786705) 22182131.67061 ulp for atanh(0.999999998603580464) = 10.5412507259525334) 16724480.03953 ulp for atanh(0.999999998101139487) = 10.3875795497842933) atanh99397551793252583.828120.99999999999999988918.3684002848385504