[R] Matrix oriented computing

Sigbert Klinke sigbert at wiwi.hu-berlin.de
Fri Aug 26 14:44:10 CEST 2005


Hi,

I want to compute the quantiles of Chi^2 distributions with different 
degrees of freedom like

x<-cbind(0.005, 0.010, 0.025, 0.05, 0.1, 0.5, 0.9, 0.95, 0.975, 0.99, 0.995)
df<-rbind(1:100)
m<-qchisq(x,df)

and hoped to get back  a  length(df) times length(x)  matrix with the 
quantiles. Since this does not work, I use

x<-c(0.005, 0.010, 0.025, 0.05, 0.1, 0.5, 0.9, 0.95, 0.975, 0.99, 0.995)
df<-c(1:100)
m<-qchisq(x,df[1])
for (i in 2:length(df)) {
  m<-rbind(m,qchisq(x,df[i]))
}
dim(m)<-c(length(df),length(x))

Is there a way to avoid the for loop ?

Thanks Sigbert




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