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)
   0.54169 ulp for atanh(0.96239053099999972) = 1.9773314069607562)
   0.52767 ulp for atanh(-0.73702754219999955) = -0.94394065940211735)
   0.52511 ulp for atanh(-0.69695149700000125) = -0.86134790730248811)
   0.52338 ulp for atanh(0.37635874979999828) = 0.39581071017738595)
   0.51975 ulp for atanh(0.11600748179999996) = 0.11653212400674044)
   0.51907 ulp for atanh(0.99999999612034807) = 10.030333786966398)
   0.51743 ulp for atanh(-0.58492832180000032) = -0.66992161928944949)
   0.51577 ulp for atanh(0.99999998573132121) = 9.3791730847151484)
   0.51573 ulp for atanh(-0.75809213999999991) = -0.99171378942479405)
   0.51516 ulp for atanh(0.99999998573121585) = 9.3791693927203141)
   0.51502 ulp for atanh(-0.40517564639999992) = -0.42982571562734068)
   0.51423 ulp for atanh(0.89597410959999946) = 1.4514241065670994)
   0.51374 ulp for atanh(0.43589809139999997) = 0.4671554279576956)
   0.51361 ulp for atanh(0.96239053100000072) = 1.9773314069607697)
   0.51348 ulp for atanh(-0.85937774019999957) = -1.2909599377758738)
   0.51344 ulp for atanh(-0.25059610779999975) = -0.25604876138056903)
   0.51220 ulp for atanh(-0.69695149700001524) = -0.86134790730251531)
   0.51181 ulp for atanh(0.83391883199999917) = 1.2008668808839833)
   0.51121 ulp for atanh(-0.58492832180000864) = -0.66992161928946214)
   0.51098 ulp for atanh(0.99999999461513223) = 9.8664101295139233)

<tr><td align=left><a href=atanh.res>atanh</a></td><td align=right>993</td><td align=right>0.54169</td><td>0.96239053099999972</td><td>1.9773314069607562</td></tr>