Actually it does that in my 2.2.1 version as well: > options(digits=20) > 8^(1:20) [1] 8.0000000000000000e+00 6.4000000000000004e+01 5.1200000000000001e+02 [4] 4.0960000000000001e+03 3.2768000000000002e+04 2.6214400000000002e+05 [7] 2.0971519999999999e+06 1.6777215999999999e+07 1.3421772800000000e+08 [10] 1.0737418240000001e+09 8.5899345920000005e+09 6.8719476736000003e+10 [13] 5.4975581388799997e+11 4.3980465111039999e+12 3.5184372088832001e+13 [16] 2.8147497671065600e+14 2.2517998136852482e+15 1.8014398509481984e+16 [19] 1.4411518807585588e+17 1.1529215046068471e+18
Peter Dalgaard wrote: > jim holtman <[EMAIL PROTECTED]> writes: > > >> The other thing that you have to be aware of is that 8^n is not 8 multiplied >> by itself n times. You are probably using logs to compute this. Here is a >> sample of 8^(1:20). The value of 8^2 is 64.000000000000004 (not exactly an >> integer); roundoff errors are apparent in the other values. >> >> >>> 8^(1:20) >>> >> [1] 8.0000000000000000e+00 6.4000000000000004e+01 5.1200000000000001e+02 >> 4.0960000000000001e+03 >> [5] 3.2768000000000002e+04 2.6214400000000002e+05 2.0971519999999999e+06 >> 1.6777215999999999e+07 >> [9] 1.3421772800000000e+08 1.0737418240000001e+09 8.5899345920000005e+09 >> 6.8719476736000003e+10 >> [13] 5.4975581388799997e+11 4.3980465111039999e+12 3.5184372088832001e+13 >> 2.8147497671065600e+14 >> [17] 2.2517998136852482e+15 1.8014398509481984e+16 1.4411518807585588e+17 >> 1.1529215046068471e+18 >> > > This was resolved a few versions back as I recall it (seems to have > eluded the NEWS file?): > > >> options(digits=20) >> 8^(1:20) >> > [1] 8.0000000000000000000e+00 6.4000000000000000000e+01 > [3] 5.1200000000000000000e+02 4.0960000000000000000e+03 > [5] 3.2768000000000000000e+04 2.6214400000000000000e+05 > [7] 2.0971520000000000000e+06 1.6777216000000000000e+07 > [9] 1.3421772800000000000e+08 1.0737418240000000000e+09 > [11] 8.5899345920000000000e+09 6.8719476736000000000e+10 > [13] 5.4975581388800000000e+11 4.3980465111040000000e+12 > [15] 3.5184372088832000000e+13 2.8147497671065600000e+14 > [17] 2.2517998136852480000e+15 1.8014398509481984000e+16 > [19] 1.4411518807585587200e+17 1.1529215046068469760e+18 > > >> 8^(1:20) %%1 >> > [1] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > Warning messages: > 1: probable complete loss of accuracy in modulus > 2: probable complete loss of accuracy in modulus > 3: probable complete loss of accuracy in modulus > > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html