[R] help me to debug this part of code?

francogrex francogrex at mail.com
Sat Apr 19 00:11:20 CEST 2008

There are a lot of syntax errors such as unclosed parentheses, missing commas
etc; Example: exp@(@lgamma((k+1)/2)-lgamma(k/2)*1/sqrt(k), where the
parenthesis between the @s is not closed. I suggest you get an editor such
as "Tinn" that can highlight those for you. In addition I notice that you
use two functions: f and g, in a loop but you didn't pass any arguments to

jinjin wrote:
> I am trying to solve the integration equation, for different values of K
> from 4 to 25, the integration is with respect to u,
> Here is the equation:    gamma(k/2) / ( sqrt(k-1)*gamma((k-1)/2) ) *
> integrate(f= (1+u^2/k-1)^(-k/2), lower=0, upper= sqrt(a^2*k/(k+1-a^2)) ) = 
> the similar expression as te left hand except k becomes k+1
> my code is below, I don't know why R keep telling me the syntax wrong but
> I am not clear, thanks.
> f<-function(u,k){(1+u^2/(k-1))^(-k/2)}
> g<-function(u,k){(1+u^2/k)^(-(k+1)/2)}
> for(k in 4:25){
> out<-uniroot(function(a){
> m<-exp(lgamma(k/2)-lgamma((k-1)/2))*1/sqrt(k-1)
> n<-exp(lgamma((k+1)/2)-lgamma(k/2)*1/sqrt(k)
> m*integrate(f,lower=0,upper=sqrt(a^2*(k-1)/(k-a^2)),rel.tol=.Machine$double.eps^0.25)
> -n*integrate(g,lower=0,upper=sqrt(a^2*k/(k+1-a^2)),rel.tol=.Machine$double.eps^0.25)
> }
> lower=1.4, upper=2)
> print(unlist(out))}

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