result of erfc is never more precise than double

5 results were exact to double the precision

20 largest ulp errors (stored in a double)
   2.50024 ulp for erfc(1.1317433216469623) = 0.10948177651485225)
   2.49689 ulp for erfc(1.6322050160252179) = 0.020983208456340122)
   1.52928 ulp for erfc(1.7576340568031921) = 0.012930783929134524)
   1.51647 ulp for erfc(1.7643804388380695) = 0.012588234115907142)
   1.51217 ulp for erfc(1.5567415012531787) = 0.027696054471658068)
   1.50153 ulp for erfc(1.1317433216470341) = 0.10948177651482971)
   1.50146 ulp for erfc(7.9767333188525988) = 1.6324629852837184e-29)
   1.50116 ulp for erfc(2.5109778156234279) = 0.00038368456802765087)
   1.50085 ulp for erfc(1.7628965046568958) = 0.012662884420711737)
   1.50016 ulp for erfc(0.931983348947232) = 0.1874957839495901)
   1.50015 ulp for erfc(15.361781366399034) = 1.1950255988861183e-104)
   1.50010 ulp for erfc(1.7410120451575597) = 0.013810194681523322)
   1.50007 ulp for erfc(1.6578653272358503) = 0.019048746777246411)
   1.50003 ulp for erfc(1.5834228908847596) = 0.025136524657301734)
   1.50001 ulp for erfc(0.81341984759759189) = 0.25000000000001543)
   1.50001 ulp for erfc(1.1519997418893739) = 0.10327626155890648)
   1.50001 ulp for erfc(1.7668753916333362) = 0.012463601778011851)
   1.50001 ulp for erfc(1.0659681717228293) = 0.13168084173825029)
   1.50000 ulp for erfc(1.3615006773545741) = 0.054172745105881936)
   1.50000 ulp for erfc(1.4111140410020768) = 0.045975669621614881)

<tr><td align=left><a href=erfc.res>erfc</a></td><td align=right>1318</td><td align=right>2.50024</td><td>1.1317433216469623</td><td>0.10948177651485225</td></tr>