Hi, maybe you rethink your calculations. Just for curiosity, what's the purpose?
First of all, using prod(1:j-1-.25) #and prod(1:j) instead of a loop is much more efficent. If you need all values for a[1] up to a[j] you can use cumprod But this doesn't get you rid of numeric overflow but 1/(1*2*3*4*..*j) * (-d)(1-d)(2-d)...(j-1-d) is the same as (-d)/1 * (1-d)/2 * (2-d)/3 ... * (j-1-d)/j (multiplication is commutative) j<-1:500 a<-cumprod((j-1-.25)/j) or am I missing something? Am 01.02.2011 21:51, schrieb Kiogou Lydie: > > > PLEASE HELP > > I actually want to do the following: > > a[j] = (1/(j!))*Π (i-1-d), j = 500, Π means product i = 1 to > j > > > > Yet, j! will stop at 170 and Π (i-1-d) at 172; so, a[j] will > not exceed 170. > > I would like to have at least 200 a[j]. > > > > WHAT SHOULD I DO? > > > > PLEASE SEE MY CODE FOR DETAIL!! > > > #################################################### > R CODE: > ################################################### > > > > d = .25 > > # generate j! > v=j=1 > for (i in 1:200){ > v[i] = i > for (i in 2:200){ > j[1]=1 > j[i] = j[i-1]*v[i] > } > } > j > > # generate aj > l=A=a=0 > for (k in 1:200){ > l[k] = (k-1-d) > for (i in 2:200){ > A[1] = l[1] > A[i] = A[i-1]*l[i] > for ( i in 1:200){ > a[i]= (1/j[i])*A[i] > } > > } > } > a > > ######################################## END CODE ################## > ##################################################################### > > > With GOD, everything is POSSIBLE. > > Avec DIEU, tout est POSSIBLE. > > > > [[alternative HTML version deleted]] > > > > > ______________________________________________ > R-help@r-project.org 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. -- Eik Vettorazzi Institut für Medizinische Biometrie und Epidemiologie Universitätsklinikum Hamburg-Eppendorf Martinistr. 52 20246 Hamburg T ++49/40/7410-58243 F ++49/40/7410-57790 ______________________________________________ R-help@r-project.org 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.