Here's a suggestion: Plot the function: x <- seq(3, 13, length=101) plot(x, y=dnorm(x, mean=8,sd=1)*log(dnorm(x,mean=8,sd=1)))
x <- seq(7.5, 8.5, length=101) plot(x, y=dnorm(x, mean=8,sd=1)*log(dnorm(x,mean=8,sd=1))) x <- seq(7.9, 8.1, length=101) plot(x, y=dnorm(x, mean=8,sd=1)*log(dnorm(x,mean=8,sd=1))) This suggests to me that you can integrate over restricted domains of x, and sum the intermediate results. Charles Annis, P.E. charles.an...@statisticalengineering.com 561-352-9699 http://www.StatisticalEngineering.com -----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 11:49 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.
