There is likely some limitation in the Ryacas interface that needs to be addressed by the Ryacas developers. yacas itself can support very large numbers so just use yacas directly.
Aside from that I, as mentioned previously in this thread, yacas returns a "yacas" object and that is a complex structure for which it makes no sense to try to use "paste". This works: > x <- Sym("3/2") > for(i in 2:5) x <- as.Sym(yacas(x*x)) > x expression(43046721/65536) but quickly comes up against some limits in Ryacas (not in yacas) if you go past 5. This also works and is even easier but may quickly generate enormous strings that might overflow the interface: > x <- Sym("3/2") > for(i in 2:5) x <- x*x > dput(x) structure("( ( ( ( 3/2 * 3/2 ) * ( 3/2 * 3/2 ) ) * ( ( 3/2 * 3/2 ) * ( 3/2 * 3/2 ) ) ) * ( ( ( 3/2 * 3/2 ) * ( 3/2 * 3/2 ) ) * ( ( 3/2 * 3/2 ) * ( 3/2 * 3/2 ) ) ) )", class = c("Sym", "character")) > x expression(43046721/65536) Using yacas directly: yacas ... In> x := 3/2 Out> 3/2 In> x := 3/2 Out> 3/2 In> x := x*x Out> 9/4 In> x := x*x Out> 81/16 In> x := x*x Out> 6561/256 In> x := x*x Out> 43046721/65536 In> x := x*x Out> 1853020188851841/4294967296 In> x := x*x Out> 3433683820292512484657849089281/18446744073709551616 In> x := x*x Out> 11790184577738583171520872861412518665678211592275841109096961/340282366920 938463463374607431768211456 In> x := x*x Out> 139008452377144732764939786789661303114218850808529137991604824430036072629 766435941001769154109609521811665540548899435521/1157920892373161954235709850086 87907853269984665640564039457584007913129639936 On 11/23/06, Paul Smith <[EMAIL PROTECTED]> wrote: > Dear All > > I am doing the following: > > > x <- yacas("3/2") > > for (i in 2:400) > + x <- yacas(paste(x,"*",x)) > > x > expression(Inf^1.260864167e+117/Inf^6.304320836e+116) > > Eval(x) > [1] NaN > > No luck this way. However, I am successful with > > > y <- yacas("(3/2)^400") > > y > expression(7.05507910865533e+190/2.58224987808691e+120) > > Eval(y) > [1] 2.732144e+70 > > If Ryacas/Yacas cannot multiply fractions with simultaenously very > large numerators and denominators, what else should I use? > > Thanks in advnace, > > Paul > > ______________________________________________ > 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 > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.