[R] Need help in calculating studentized residuals/leverage values of non-linear model [nls()]

[Giam Xingli]

Hi Kevin,
 
I need the studentized residuals. In linear models, they can be computed by using rstudent( ) function, but there seems to be no such function for nls( ) output.
 
Alternatively, it'll be helpful if I could compute the leverage values.
 
Best,
Xingli