This is an addition to my previous message. 16 digits are indeed not sufficient to represent a double value exactly. The next table is calculated in bc calculator. It shows that if we restrict (or round) double values to 16 decadic digits then from 4 to 5 consecutive distinct double values get the same 16 digit decadic code.
1.234567890123456 a 16-digit number for comparison 1.0000000000000000000000000000 1 + 0*2^(-52) 1.0000000000000002220446049250 1 + 1*2^(-52) 1.0000000000000004440892098500 1 + 2*2^(-52) 1.0000000000000006661338147750 1 + 3*2^(-52) 1.0000000000000008881784197001 1 + 4*2^(-52) 1.0000000000000011102230246251 1 + 5*2^(-52) 1.0000000000000013322676295501 1 + 6*2^(-52) 1.0000000000000015543122344752 1 + 7*2^(-52) 1.0000000000000017763568394002 1 + 8*2^(-52) 1.0000000000000019984014443252 1 + 9*2^(-52) 1.0000000000000022204460492503 1 + 10*2^(-52) 1.0000000000000024424906541753 1 + 11*2^(-52) 1.0000000000000026645352591003 1 + 12*2^(-52) 1.0000000000000028865798640254 1 + 13*2^(-52) 1.0000000000000031086244689504 1 + 14*2^(-52) 1.0000000000000033306690738754 1 + 15*2^(-52) 1.0000000000000035527136788005 1 + 16*2^(-52) 1.0000000000000037747582837255 1 + 17*2^(-52) 1.0000000000000039968028886505 1 + 18*2^(-52) 1.0000000000000042188474935755 1 + 19*2^(-52) Petr. ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
