thank you very much for your suggestion! I tried to do that with the psf I need to use: the 3 parameters Lognormal. I did that with a single xstar and a single triplet of parameters to check it works.[I put some numbers to make it woks , but actually they comes from statistical analysis]
/# these are the 3 parameters a<- 414.566 b<- 345.5445 g<- -0.9695679 xstar<- 1397.923 #I create a vector pars <-expand.grid(xstar = xstar, a= a, b= b , g= g) fun <- function(xstar, a,b,g,k) { f <- function(x, xstar, a, b,g,k) f.lognorm(x) * k * x * (x >= xstar) integrate(f, -Inf, Inf, xstar = xstar, a = a, b =b, g=g, k=k)$value } # Method 1: (outputs a data frame) library(plyr) out <- mdply(pars, fun)/ at this stage a warning message comes out: *Errore in k > -1e-07 : 'k' is missing* Any ideas of why this error come out ? I really don' know..... Moreover , can I use the algorithm suggested iteratively by using a grid of xstar values and different triplets of parameters ( instead of different value of k) ? Thank you so much for any help!! -- View this message in context: http://r.789695.n4.nabble.com/Numerical-integration-tp3634365p3637092.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.