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)
   159.50068 ulp for erfc(13.5907577317324684) = 2.50637651540794352e-82)
   158.50000 ulp for erfc(13.590757731735053) = 2.50637651523138843e-82)
   158.49858 ulp for erfc(13.5907577317326176) = 2.50637651539775093e-82)
   158.49437 ulp for erfc(13.590757731732916) = 2.50637651537736515e-82)
   158.47032 ulp for erfc(13.5907577317329338) = 2.50637651537615172e-82)
   157.50030 ulp for erfc(13.5907577317426576) = 2.50637651471191548e-82)
   129.50157 ulp for erfc(14.0942248283321341) = 2.13759896886214887e-88)
   129.49986 ulp for erfc(14.094224828334605) = 2.13759896871288967e-88)
   129.49973 ulp for erfc(14.09422482833169) = 2.13759896888897475e-88)
   129.46135 ulp for erfc(14.0942248283320808) = 2.13759896886536799e-88)
   128.50013 ulp for erfc(14.0942248283384917) = 2.13759896847810985e-88)
   128.48146 ulp for erfc(14.0942248283321074) = 2.13759896886375871e-88)
   95.54189 ulp for erfc(13.9712777837578717) = 6.79635392698855754e-87)
   95.50050 ulp for erfc(13.9712777837393123) = 6.79635393052210485e-87)
   95.49754 ulp for erfc(13.9712777837570581) = 6.79635392714345466e-87)
   95.49745 ulp for erfc(13.9712777837578574) = 6.79635392699126321e-87)
   94.50162 ulp for erfc(13.9712777837345161) = 6.79635393143525444e-87)
   93.50975 ulp for erfc(13.8274680330316695) = 3.74057935759410418e-85)
   93.50074 ulp for erfc(13.8274680329711952) = 3.74057936386617148e-85)
   93.45457 ulp for erfc(13.827468032969362) = 3.74057936405630114e-85)

<tr><td align=left><a href=erfc.res>erfc</a></td><td align=right>1318</td><td align=right>159.50068</td><td>13.5907577317324684</td><td>2.50637651540794352e-82</td></tr>