result of y1 is never more precise than double

20 largest ulp errors (stored in a double)
   41762958158186624.00000 ulp for y1(-2.2250738585072019e-308) = -1.7976931348623157e+308)
   41762958158186624.00000 ulp for y1(-2.2250738585072014e-308) = -1.7976931348623157e+308)
   1790336701939282.00000 ulp for y1(30.618286491641115) = -2.0761463706193708e-17)
   982087171622987.25000 ulp for y1(24.331942571356912) = 5.3593891559238665e-17)
   675254466837286.25000 ulp for y1(27.475294980449224) = 6.9447222952238642e-17)
   645495150499175.75000 ulp for y1(43.188218097393211) = 5.7708294202079462e-17)
   316536330959503.00000 ulp for y1(21.188068934142212) = -1.8041634448146089e-16)
   222713371980367.94000 ulp for y1(40.045944640266875) = -1.9138112316177136e-16)
   194696821781926.62000 ulp for y1(36.903555316142949) = 1.380730241989042e-16)
   175668378548451.31000 ulp for y1(21.188068934142215) = 4.3600616583019708e-16)
   83046814263632.28100 ulp for y1(27.47529498044922) = -4.7134331927660062e-16)
   82631570198748.39100 ulp for y1(21.188068934142208) = -7.9563607916324248e-16)
   65635024896857.94500 ulp for y1(55.756544879208136) = -6.7657392315322029e-17)
   62384158461818.34400 ulp for y1(24.331942571356915) = -5.2078671588453901e-16)
   58656862199822.98400 ulp for y1(58.898496171433052) = -1.7052173678814502e-16)
   56870031779214.10900 ulp for y1(46.330399250701689) = 2.3649230307464938e-16)
   54910311371266.97700 ulp for y1(30.618286491641111) = 4.9152139979121257e-16)
   54616903240013.79700 ulp for y1(40.045944640266882) = 7.0450125451893209e-16)
   47372349771264.48400 ulp for y1(36.903555316142956) = -7.9517302715210495e-16)
   45741412817704.73400 ulp for y1(49.472505679924097) = -1.8005677111762044e-16)

<tr><td align=left><a href=y1.res>y1</a></td><td align=right>987</td><td align=right>41762958158186624.00000</td><td>-2.2250738585072019e-308</td><td>-1.7976931348623157e+308</td></tr>