Try: > tmpfun <- function(x) dnorm(x,mean=8,sd=1)*log(dnorm(x,mean=8,sd=1)) > integrate( tmpfun, -Inf, Inf)
Also you may want to look at the log argument to dnorm rather than taking the log of the function. Hope this helps, -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Trafim Vanishek > Sent: Thursday, February 11, 2010 9:49 AM > To: Peter Dalgaard > Cc: r-help@r-project.org > Subject: Re: [R] Integral of function of dnorm > > This is exactly what I mean. > > I need to find integrate(dnorm(mean=8,sd=1)*log(dnorm(mean=8,sd=1)), - > Inf, > Inf) > > Which doesn't work like that, because it says: > Error in dnorm(mean = 8, sd = 1) : element 1 is empty; > the part of the args list of '.Internal' being evaluated was: > (x, mean, sd, log) > > So how can I define x? > THanks a lot > > > > Dear all, > >> > >> How is it possible in R to calculate the following integral: > >> Integral(-Inf, Inf)[log(dnorm(mean = 3, sd = 1))] > >> > >> how can I define that the density dnorm is taken on (-Inf, Inf) > >> > >> Thanks a lot! > >> > > > > Er, if you mean integral with respect to the x argument in dnorm, > then the > > answer is -Inf because log(dnorm(x,...)) goes quadratically to -Inf > in both > > directions. If you meant otherwise, please tell us what you meant... > > > > [[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. ______________________________________________ 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.